Documents released

Documents released
FOI Document #1
Co
s47F
From:
Sent:
To:
Cc:
Subject:
Attachments:
s47F
@qenos.com
Friday, 24 October 2014 9:29 AM
TARCON
s47F
Qenos objection to TC1425824
HDF193B-CON item cost.xlsx; Qenos invoices HDF193B CON 2014.pdf; TC 1425824
objection Oct 14 signed.pdf; Polyethylene at a Glance 6th Edition.pdf; Book 7 Pipe and
Tubing Extrusion_web.pdf
Dear National Manager, Tariff Branch
Please find attached Qenos' objection to Gazette no TC 14/33, TC 1425824 and supporting material.
s47F
s47F
Qenos Pty Ltd
P: s47F
I M: s47F
E: s47F
cienos.com
W: www.qenos.com
Qenos
A
Innywt
1
FOI Document #2
Se\
•
*
*so
TIME
SAVER
If this form was completed by a business with fewer than 20 employees,
please provide an estimate of the time taken to complete this form.
I
Hours
j Minutes
SUBMISSION OBJECTING TO THE MAKING OF A
TARIFF CONCESSION ORDER (TCO)
THIS FORM MUST BE COMPLETED BY A LOCAL MANUFACTURER WHO WISHES TO OBJECT TO THE GRANTING OF A TCO.
THE INFORMATION PROVIDED ON THIS PAGE WILL BE FORWARDED TO THE APPLICANT FOR THE TCO.
THE FORM SHOULD BE READ CAREFULLY BEFORE BEING COMPLETED.
DETAILS OF THE TCO APPLICATION TO WHICH THIS SUBMISSION REFERS
GAZETTE NO TC 14/33
DATE 23 October 2014
Gazetted description of goods.
TC Reference Number
TC
1425824
RESINS, being unpigmented polypropylene hetrophasic copolymer,
propylene based with comonomer ethylene, in pelletised form,
having ALL of the following: (refer TC 1425824)
Stated use: For the manufacture of corrugated and smooth bore pipes for use in
drainage and storm water removal
LOCAL MANUFACTURER DETAILS
Name
Qenos
Business Address
417-513 Kororoit Creek Road, Altona VIC 3018
Postal Address (lithe same as business address write "as above")
Private Mail Bag 3, Altona VIC 3018
Australian Business Number (A.B.N.)
Reference
62 054 196 771
Company Contact
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Phone Number
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Facsimile Number
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E-mail Address
@genos.conn
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DETAILS OF THE SUBSTITUTABLE GOODS PRODUCED IN AUSTRALIA
1
Describe the locally produced substitutable goods the subject of the objection.
"Substitutable goods" are defined in the Customs Act 1901 as "goods produced in Australia that are put, or are capable of being put, to a use that
con-esponds with a use (including a design use) to which the goods the subject of the application or of the TCO can be put".
High density polyethylene (HDPE) pipe resin
2
State the use(s) to which the substitutable goods are put or are capable of being put.
Pipes and fittings
'13444 (JUN 2001
FOI Document #2
3
Attach technical, illustrative descriptive material and/or a sample to enable a full and accurate identification and
understanding of the substitutable goods.
4
Are you aware of any other local manufacturers producing substitutable goods?
5
If yes to question 4, please provide details of any goods produced in Australia which are substitutable for the goods for
which a TCO is being sought, and the names and addresses of the manufacturers of those goods.
6
PRODUCTION OF GOODS IN AUSTRALIA
El YES El NO
Goods other than unmanufactured raw products will be taken to have been produced in Australia if:
(a)
the goods are wholly or partly manufactured in Australia; and
(b)
not less than 1/4 of the factory or works costs of the goods is represented by the sum of:
(i) the value of Australian labour; and
(ii) the value of Australian materials; and
(iii) the factory overhead expenses incurred in Australia in respect of the goods.
Goods are to be taken to have been partly manufactured in Australia if at least one substantial process in the manufacture of the goods
was carried out in Australia
Without limiting the meaning of the expression 'substantial process in the manufacture of the goods", any of the following operations or
any combination of those operations DOES NOT constitute such a process:
(a)
operations to preserve goods during transportation or storage;
(b)
operations to improve the packing or labelling or marketable quality of goods;
(c)
operations to prepare goods for shipment;
(d)
simple assembly operations;
(e)
operations to mix goods where the resulting product does not have different properties from those of the goods that have been mixed.
A
Are the goods wholly or partly manufactured in Australia?
Ej YES 12 NO
Does the total value of Australian labour, Australian materials and factory overhead
expenses incurred in Australia represent at least 25% of the factory or works costs?
0 YES 0 NO
Specify each of the following costs per unit for the substitutable goods:
s47
•
Australian labour
•
Australian materials
s47G
•
Australian factory overhead expenses
s47G
•
Imported content
s47G
TOTAL
s47G
s
4
s
7
4
G
s
7
4
G
7
G
Specify the date or period to which the costs relate. 12 months to end Sep 2014
Attach a copy of the working papers that were used to prepare the above costing information. Those working papers should be
supported by (at least two) extracts from the accounting records of the business.
Is at least one substantial process in the manufacture of the goods carried out in Australia? El YES El NO
If yes, please specify at least one major process involved:
Conversion of ethane gas supplied form Bass Strait into ethylene using a steam cracking process and then
polymerised into polyethylene at Qenos's Altona Victoria polymer manufacturing facility
FOI Document #2
51
7
PRODUCTION OF GOODS IN THEORDINARYCOURSE OF BUSINESS
(Answer 7.1 or 7.2)
7,1
SUBSTITUTABLE GOODS OTHER THAN MADE-TO-ORDER CAPITAL EQUIPMENT
Substitutable goods (other than made-to-order capital equipment) are taken to be produced in Australia in the ordinary course of business if:
(a)
they have been produced in Australia in the 2 years before the application was lodged: or
(b)
they have been produced, and are held in stock, in Australia; or
(c)
they are produced in Australia on an intermittent basis and have been so produced in the 5 years before the application was
lodged;
and a producer in Australia is prepared to accept an order to supply such goods.
A
Have the goods been produced in Australia in the last 2 years?
El YES
D NO
•
Have the goods been produced and are they held in stock in Australia?
E3
YES
D NO
•
If the goods are intermittently produced in Australia, have they been so produced
El YES
D NO
Z YES
D NO
in the last 5 years?
•
Are you prepared to accept an order for the goods?
7.2
SUBSTITUTABLE GOODS BEING MADE-TO-ORDER CAPITAL EQUIPMENT
"Made-to-order capital equipment" means a particular item of capital equipment that is made in Australia on a one-off basis to meet
a specific order rather than being the subject of regular or intermittent production and that is not produced in quantities indicative of
a production run. Capital equipment means goods which, if imported, would be goods to which Chapters 84, 85, 86, 87, 89 or 90
of Schedule 3 to the Customs Tariff Act 1995 would apply.
Goods that are made-to-order capital equipment are taken to be produced in Australia in the ordinary course of business if:
(a)
a producer in Australia:
(i)
has made goods requiring the same labour skills, technology and design expertise as the substitutable goods in the 2 years
before the application; and
(ii)
could produce the goods with existing facilities; and
(b)
the producer in Australia is prepared to accept an order to supply the substitutable goods.
•
Have goods requiring the same labour skills, technology and design expertise as the
goods the subject of the application been made in Australia in the last 2 years?
DYES 0 NO
If yes, describe the goods made during this period:
Can the goods be produced with existing facilities?
•
Are you prepared to accept an order for the goods?
8
What was the first date on which you were prepared to accept an order?
Are the goods still in production?
If the answer is no, when did production cease?
If production has ceased and goods are held in stock, please estimate the date by
which stock is expected to be sold, based on past sales information and attrition
rate of the local goods.
• YES
Ei NO
YES
0 NO
D
1 /1 /2003
E
YES
DN0
FOI Document #2
9
Provide any additional information in support of your objection.
Cost analysis based on the bill of materials (provided) for Qenos grade HDF193B packaged in 20 tonne
bulk containers for local delivery.
This product has been in production for over 10 years - the answer to question 8 on the first date
on which Qenos was prepared to accept an order is indicative only.
A copy of Qenos' product guide "Polyethylene at a glance" and Qenos' technical guide on
pipe and tubing extrusion have been provided in response to question 3.
NOTES
(a) Section 269K and 269M ofthe Customs Act1901 requirethat a submission opposing the making of a TCO be in writing,
be in an "approved form", contain such information as the form requires, and be signed in the manner indicated in the
form. This is the approved form for the purposes of those sections.
(b) A submission will be date stamped on the day it is first received in Canberra by an officer of Customs. The submission
is taken to have been lodged on that day.
(c) For the submission to be taken into account, it must be lodged with Customs:
• no later than 50 days after the gazeftal day for an application for a TCO;
• no later than 14 days after the gazeftal day for an amended application for a TCO; or,
• where the Chief Executive Officer has invited a submission, within the period specified in the invitation.
(d) Every question on the form must be answered.
(e) Where the form provides insufficient space to answer a question, an answer may be provided in an attachment. The
attachment should clearly identify the question to which it relates.
(f) Unless otherwise specified, all information provided should be based on the situation as at the date of lodgement of the
TOO application.
(g) Customs may require an objector to substantiate, with documentary evidence, information provided in relation to the
objection.
(h) Further information on the Tariff Concession System is available in Part XVA of the Customs Act 1901, in the foreword
to the Schedule of Concessional Instruments, in the administrative guidelines in Volume 13 of the Australian Customs
Service Manual, in Australian Customs Notice No. 98/19, on the internet at www.customs.gov.au, by e-mailing
[email protected] au or by phoning the Customs Information Centre on 1300 363 263.
I agree, in submitting this form by electronic means (including facsimile) that, for the purposes of Sub-Section 14(3) of the
Electronic Transactions Act, this submission will betaken to have been lodged when it is first received by an officer of Customs,
or if by e-mail, when it is first accessed by an officer of Customs, as specified in Sub-Section 269F(4) of the Customs Act.
Full Name
Position Held
s47F
s47F
Signature
s47F
Date
24 October 2014
NOTE:
SECTION 234 OF THE CUSTOMS ACT 1901 PROVIDES THAT IT IS AN OFFENCE TO MAKE A STATEMENT TO AN
OFFICER THAT IS FALSE OR MISLEADING IN A MATERIAL PARTICULAR.
WHEN THIS FORM HAS BEEN COMPLETED LODGE IT WITH CUSTOMS BY:
• posting it by prepaid post to the
National Manager, Tariff Branch
Australian Customs Service
Customs House
5 Constitution Avenue
CANBERRA ACT 2601
Or
• delivering it to the ACT Regional Office located at
Customs House, Canberra
or
• sending it by facsimile to (02) 6275 6376
Or
• e-mailing it to [email protected]
FOI Document #5
Polyethylene
at a Glance
Oenos
A Bluestar Company
FOI Document #5
51
AlkadyneTM PE100 Pipe Extrusion Grades
Grade
Melt Index*
(g)10 mm a 190 C
5 00kg)
Density#
Applications
)g/cm )
HDF193B
0.3
0.9610)
High Density black PE100 type resin certified to AS/NZS 4131, for use in pressure pipes and fittings. Excellent low
sag properties and throughput, suitable for the majority of PE100 pipe dimensions.
HDF145B
0.2
0.9610)
High Density black PE100 type resin certified to AS/NZS 4131, for use in pressure pipes and fittings. Exceptional
low sag properties and throughput, suitable for the most challenging pipe dimensions.
HDF193N
0.3
0.9520)
High Density natural resin for extrusion into a full range of non standard pipe products and as a base for PE100
type striping and jacket compounds.
Notes: (1)ASTM D1505/D2839
Alkadyne'PE Pipe Extrusion Grades
Melt Index*
Density#
Grade
(g/10 min @ 1901C,
5.00kg)
MD0898
0.7
0.952(1)
Medium Density black PE8OB type resin certified to AS/NZS 4131 for use in pressure pipes and fittings.
) MD0592
0.6
0.9420)
Medium Density natural resin for extrusion into a full range of non standard pipe products and as a base for PESO
type striping and jacket compounds.
GM7655
0.6
0.9540)
High Density natural high molecular weight resin for extrusion into a full range of non standard pipe products.
MDF169
1.0
0.9430)
Medium Density natural high molecular weight resin for extrusion into a full range of non standard pipe products.
LL0228
1.7(2)
0.9230)
Linear Low Density resin for use in pipe extrusion applications.
Notes: 0) ASTM D1505/D2839
Applications
[email protected]°C, 2.16kg
AlkadyneTM PE Wire and Cable Grades
Grade
Melt Index
(g)10 min p
.t, 190C,
2 16kg)
Density#
(g)cm
Applications
MD0592
0.12
0.9420)
Designed for extrusion into a full range of wire and cable products where natural Medium Density resins are required.
MD0898-1
0.12
0.9530)
Designed as general purpose jacketing compound for buried wires and cables where abrasion and cut through
resistance is required.
Notes: (1) ASTM D1505/D2839
AlkataneHDPE Tape and Monofilament Grades
Grade
Melt Index*
(9110 mm @ 190'C,
2 16kg)
GF7740F2
0.4
Density#
(g)cm')
0.950(1)
Applications
Extrusion applications including stretched tape, monofilament, tarpaulins, and over-pouches for medicinal products.
Notes: )"ASTM D1505/D2839
Alkatuff® LLDPE Rotational Moulding Grades
Melt Index.
(g110 min Cy 190'C.
2.16kg)
Density'
ly 0111 I
App [cation •
LL711UV
3
0.938
Applications requiring excellent ESCR, chemical resistance(1), stiffness, toughness and UV protection, such as
water and chemical tanks, septic systems and kayaks.
LL705UV
5
0.935
Applications requiring high ESCR, chemical resistance(1), toughness, stiffness and high level UV stabiliser, such as
leisure craft, playground equipment and agricultural tanks.
LL755
5
0.935
Applications requiring high ESCR, chemical resistance(1), toughness and stiffness. Incorporation of suitable UV
stabilisation is required for outdoor applications.
10
0.930
High speed intricate applications requiring good ESCR, chemical resistance(1), toughness and UV protection,
such as consumer goods and playground equipment.
LL710UV
Notes: '1) The level of chemical resistance is a function of product design and environmental conditions. Contact Qenos for further information.
*Melt
Index according to ASTM D1238 unless otherwise annotated
°Density according to ASTM D1505 unless otherwise annotated
FOI Document #5
G-C)
Additives
Alkathene® LDPE Film Grades
Grade
Melt Index*
(010 min @ 190°C,
2.16kg)
Density#
(g/cm')
co
co
cci
>-•
'5
Applications
o
u
0
er..
Applications
Cl)
=
co
v
v
v
v
v
v
v'
V
co
cn
a.,
a
.
co
o_
o
XDS34
030
0.922
Heavy duty sacks, pallet wrap and industrial applications requiring heavy gauge
film. Additive free.
LDF433
0.45
0.925
Heavy duty sacks, pallet wrap and industrial applications requiring medium to
heavy gauge film with increased stiffness.
LDD201
0.45
0.922
General purpose medium to heavy gauge film for heavy duty bags and shrink
film and for use as a blend component.
LDD203
0.45
0.922
General purpose medium to heavy gauge film for heavy duty bags and shrink
film requiring antiblock, and for use as a blend component
v
LDD204
0.45
0.922
General purpose medium to heavy gauge film for heavy duty bags and shrink
film where a medium level of slip is required.
v
m
v
v
LDD205
0.45
0.922
General purpose medium to heavy gauge film for heavy duty bags, frozen food
and produce bags where a high level of slip is required or for use as a blend
component.
V
H
V
V
V
LDH210
1.0
0.922
Bundle shrink and other medium gauge film applications such as produce bags,
carry bags and for blending into other film grades.
V
V
V
LDH215
1.0
0.922
General purpose medium gauge film for produce bags and carry bags, frozen
food where a high level of slip is required or for use as a blend component.
V
V
XJF143
2.5
0.921
Additive free, general purpose low gauge film for overwrap and other
applications and for use as a blend component.
LDJ226
2.5
0.922
Bundle shrink, low gauge shrink film and general purpose applications where a
medium level of slip and antistatic are required.
LD0220MS
2.5
0.922
LDJ225
2.5
XLF197
5.5
/
v
H
,c2
co
.g
II
it,
a.
co
3 il
o
g
V
v
v
No,
High quality low gauge film for lamination and overwrap applications where a
medium level of slip is required.
V
M
0.922
High quality, low gauge film primarily intended for bread bags and overwrap but
also general purpose applications where a very high level of slip is required.
v
VH
0.920
High quality, very thin gauge and high clarity film primarily intended for food and
packaging wrap and for drycleaning film. Additive free.
i
v
v
V
v
v
v
Notes: 0) Based on antistat additive ii VH = Very High Slip, H = High Slip, M = Medium Slip
Additives
Alkatuff® LLDPE Film Grades
Melt Index
Applications
•
Density''
is c
Applications
Grade
(g110 min @ 190-C.
2.16kg)
LL438
0.8
0.922
Heavy duty sacks, agricultural films,lamination and form, fill and seal
packaging where enhanced toughness and sealing characteristics are
desired.
//
VV
LL501
1.0
0.925
General purpose industrial, agricultural and heavy duty films and as a
blend component to improve film handling in converting and packaging
operations.
V
V
LL601
1.0
0.925
General purpose industrial, agricultural and heavy duty films and as a
blend component to improve film handling in converting and packaging
operations.
LL425
2.5
0.918
High quality cast film for applications that require toughness,
high clarity and processability.
Notes: (1) VH = Very High Slip, H = High Slip, M = Medium Slip
*Melt Index according to ASTM D1238 unless otherwise annotated
#Density according to ASTM D1505 unless otherwise annotated
V
V
V
V V
V
V
FOI Document #5
Alkamax° mLLDPE Film Grades
Additives
Applications
cn
Grade
Melt Index
(g/10 min @
190'C, 2.16kg)
Density#
(g/cm')
CO
cn
Applications
V,
cn
6
2
ML1810PN
1.0
0.918
Heavy duty bags, industrial and agricultural films, and
form, fill and seal applications and ice bags where
outstanding toughness, sealing and hot tack properties
are desirable or for downgauging of existing film
structures.
ML1810PS
1.0
0.918
Heavy duty bags,industrial and form, fill and seal
applications and ice bags where outstanding toughness,
sealing, hot tack properties and high slip are desirable
or for downgauging of existing film structures.
ML2610PN
1.0
0.926
Heavy duty bags, lamination, industrial and form, fill
and seal applications where outstanding stiffness,
toughness, optical and sealing properties are desirable
or for downgauging of existing film structures.
L1710SC
1.0
0.917
Stretch cling films (with addition of appropriate cling
additive) and other film applications where outstanding
toughness, optical and sealing properties are desirable
or for downgauging of existing film structures.
Cr
V
V
-2
2
co
,/ V V V
V
V
V
.c75
V
V
V
V V
V
V
V
V V
V
V
V
V
V
V
V
Notes: m VH = Very High Slip, H = High Slip, M = Medium Slip
Alkatane" HDPE Film Grades
Grade
Melt Index
(g/10 min @
190"C, 2.16kg)
Density#
(glcm')
Applications
Applications
GM4755F
0.10
0.955m
Carry bags and liners where high impact, toughness and stiffness are desirable and as a blend component into
LDPE and LLDPE films for heavy duty applications.
HDF895
0.80
0.960m
Moisture barrier and blend component into LDPE and LLDPE films to enhance stiffness. Blend component in core
layer for high clarity coextruded films.
V V
V
V
Notes: mASTM D1505/D2839
AlkataneTM HDPE Blow Moulding Grades
Melt Index*
Density'
Grade
(9/10 min @ 190'C,
2.16kg(
HD0840
0.06
0.95311 /
Large part blow mouldings, especially blow moulded self-supported drums and tanks (25 - 220 litres).
Exceptional ESCR.
HD1155
0.07
0.953m
Large part blow mouldings, including 25 litre to 220 litre tanks and drums. Exceptional ESCR.
GM7655
0.09
0.954m
Blow moulded containers including household and industrial chemical (HIC). Suitable for larger part mouldings.
Exceptional ESCR.
GF7660
0.30
0.959m
Household and industrial chemical (H IC) containers, including detergent and pharmaceutical bottles.
Excellent ESCR.
GE4760
0.60
0.96401
Blow moulded water, dairy and fruit juice bottles.
HD5148
0.83
0.962m
High speed dairy packaging applications and other thin walled bottles such as milk, cream, fruit juice and cordial.
(gice)
Applications
Notes: ASTM 01505/02839
Qenos imported polymers and additives
Complementing our Australian manufactured Polyethylene grades, Qenos acts as a local distributor for a wide range of imported polymers and additives including rubbers,
elastomers, adhesives, plastomers, EVA, BOPP Film, EPS, antioxidants and titanium dioxide. For the full Qenos range, please refer to the Qenos website, Customer Service or your
Account Manager.
*Melt Index according to ASTM 01238 unless otherwise annotated
#Density according to ASTM D1505 unless otherwise annotated
V
FOI Document #5
Lf-s
Alkathene® LDPE Extrusion Coating Grades
Melt Index*
Density*
Grade
(g/10 min @ 190C,
2.16kg)
XLC177
4.5
0.923
Applications including milkboard and fabric extrusion coating where very good drawdown, low moisture vapour
transmission rates and excellent hot tack are desirable. Additive free.
WNC199
8.0
0.918
Liquids packaging and other sensitive food packaging laminates where excellent heat seal, low extractables, good
melt strength and low odour and taint are desirable. Additive free.
LDN248
7.6
0.922
Liquids packaging and other sensitive food packaging laminates where low extractables and low odour and taint are
desirable. Additive free.
LD1217
12
0.918
Liquids packaging and other sensitive food packaging laminates where high line speed, low neck-in, low
extractables and low odour and taint are desirable. Additive free.
)g/cm)
Applications
Alkathene® LDPE Injection Moulding Grades
Melt Index*
Density*
Grade
(g/10 mm @ 190'C,
2.16kg)
XDS34
0.3
0.922
Small part injection moulded caps and closures. Additive free.
WJG117
1.7
0.918
Thick section mouldings, caps and closures, industrial containers where a high level of toughness is desirable.
Additive free.
XJF143
2.5
0.921
Injection moulded caps and closures, and thick-walled sections. Additive free.
LDN248
7.6
0.922
Injection moulded caps and closures. Additive free.
WRM124
22
0.920
High flow resin for reseal lids, housewares and toys where excellent gloss, low warpage and flow to toughness ratio
are desirable. Additive free.
LD6622
70
0.922
High flow resin for lids and other thin wall injection moulding applications. Additive free.
(g/cm')
Applications
Alkatuff® LLDPE Injection Moulding Grades
Melt Index'
Grade
LL820
(g/10 mm @ 190 C
2.16kg)
20
Density=
(g ,cm )
0.925
Applications.._,
Injection moulding and compounding applications such as housewares and lids.
Alkatane HDPE Injection Moulding Grades
Melt Index*
Density*
Grade
410 mm @ 190°C,
2.16kg)
HD0390
4
0.955
Stackabie crates for transport, storage and bottles and industrial mouldings where very good mechanical properties
are des able.
HD0397UV
4
0.955
Mouldings requiring long-term weatherability, including mobile garbage bins, crates, and industrial mouldings where
very good mechanical properties are desirable.
HD0490
4.5
0.955
Stackable crates for transport, storage and bottles, and industrial mouldings where very good mechanical properties
are desirable.
HD0499UV
4.5
0.955
Mouldings requiring long-term weatherability, including mobile garbage bins, crates, and industrial mouldings where
very good mechanical properties are desirable.
HD0790
7
0.956
Industrial pails, crates, closures and sealant cartridges where a good balance between flow and impact resistance is
desirable.
HD1090
10
0.956
Industrial pails, crates, closures and sealant cartridges where a good balance between flow and impact resistance is
desirable.
HD1099UV
10
0.956
Mouldings requiring long term weatherability including industrial pails, crates, and tote boxes where a good balance
between flow and impact resistance is desirable.
HD2090
20
0.956
Housewares, thin-walled containers and closures where excellent mould flow and flexibility is required.
HD3690
36
0.956
Housewares, thin-walled mouldings and closures where excellent mould flow and flexibility is required.
(glcm')
*Melt Index according to ASTM 01238 unless otherwise annotated
Applications
°Density according to ASTM 01505 unless otherwise annotated
FOI Document #5
14'7
Qenos Pty. Ltd.
ABN: 62 054 196 771
Cnr Kororoit Creek Road & Maidstone Street,
Altona Victoria 3018, Australia
1: 1800 063 573 F: 1800 638 981
[email protected]
qenos.com
OW*
60 OOP
0111014l01101.
A
AAA-ITALIAN MADE
Front Cover: Pellet geometry and pellet quality can have a significant effect on material flow and the efficiency of feeding polyethylene into an extruder. Qenos
measures pellet quality using a pellet shape arid size distribution analyser, a device that photographs around 10,000 pellets in 4 minutes, digitally analyses
the images and generates a report on pellet quality. Where a drift in the pellet quality is detected, adjustments are made proactively to maintain high product
integrity.
Rear Cover: The standard for UV performance for PE Water Tanks specified in AS/NZS 4766 PE Tanks for the Storage of Chemicals and Water is 8,000 hours of
uninterrupted exposure to an intense and specifically developed UV light source. Qenos exhaustively tests the long term UV performance of its Rotational Moulding
Resins under conditions of controlled irradiance, chamber temperature and humidity and repeated rain cycles. Alkatuff0 711UV achieves a class leading LIV
performance exceeding 20,000 hours against the required standards, ensuring that Alkatuff® 711UV is "Tough in the Sun':
The contents of this document are offered solely for your consideration and verification and should not be construed as a warranty or representation for which Qenos Pty Ltd assumes legal liability, except
to the extent that such liability is imposed by legislation and cannot be excluded. Values quoted are the result of tests on representative samples and the product supplied may not conform in all respects.
Qenos Pty Ltd reserves the right to make any improvements or amendments to the composition of any grade or product without alteration to the code number. The applications listed are based on the usage
by exisiting Qenos customers. In using Qenos Pty Ltd's products, you must establish for yourself the most suitable formulation, production method and control tests to ensure the uniformity and quality of
your product is in compliance with all laws and your requirements.
Qenos, Alkathene, Alkatuff, Alkamax, Alkadyne and Alkatane are trade marks of Qenos Pty. Ltd.
6th Edition November 2013
Qenos
—
A Bluestar Company
FOI Document #6
Own
7
AlkadyneTM
PIPE AND TUBING
EXTRUSION
TECHNICAL GUIDE
FOI Document #6
14s-
Front Cover:
Polyethylene pipe is an engineered product, required to withstand
internal pressure and external influences for up to 100 years.
Qenos has invested in the largest pipe pressure testing facility
in the southern hemisphere, where Alkadyne PE100 pipe resin
is extruded for testing and then subject to high pressure and
elevated temperature for up to three years. This testing is also
applied to specially notched pipe samples to ensure damage
during installation does not result in premature failure. Alkadyne
PE100 pipe resin - Engineered to Outperform.
Qenos and Alkadyne are trade marks of Qenos Pty. Ltd.
FOI Document #6
PIPE AND TUBING 7
EXTRUSION
FOI Document #6
43
7 PIPE AND TUBING EXTRUSION
CONTENTS
INTRODUCTION
6
PIPE APPLICATION REQUIREMENTS
6
CLASSIFICATION OF POLYETHYLENE PIPE AND PIPE COMPOUNDS
6
ALKADYNE GRADE SELECTION FOR PIPE
7
PIPE EXTRUSION TECHNOLOGY
7
Granule Pre-treatment
7
Extruder
8
Pipe Dies
9
Sizing and Cooling
10
Downstream Equipment
11
Process Control
13
MECHANICAL PERFORMANCE OF POLYETHYLENE PIPE GRADES
13
Short-term Behaviour at Low Deformation Rates
13
Long-term Behaviour
14
Creep Behaviour Under Uniaxial Stress
14
Creep Test
14
Relaxation Test
15
Behaviour at High Deformation Rates
15
QUALITY TESTING OF POLYETHYLENE PIPE
15
PE 100: a Package of Good Properties
15
Hydrostatic Pressure Tests
15
Creep Test Under Internal Pressure
15
Pipe Pressure Curve And Service Life Extrapolation
17
Determining The Temperature Of The Pipe Wall
18
Determining The MAOP Value
19
NOTCH RESISTANCE (SCG) OF PE PIPES
20
Pipe Notch Test
20
RESISTANCE TO RAPID CRACK PROPAGATION (RCP) OF PE PIPES
20
S4 Test
21
JOINING PE PIPES
22
Butt Fusion Jointing of PE Pipes and Fittings
23
Relevant Standards
23
Jointing Procedures
23
Electrofusion Jointing of PE Pipes and Fittings
24
SDR Pipe to Fitting Fusion Compatibility
25
Electrofusion Socket Jointing
26
2
Qenos Technical Guides
FOI Document #6
PIPE AND TUBING EXTRUSION 7
Equipment
26
1. Control Box
26
2. Peeling Tools
27
3. Re-rounding and Alignment Clamps
27
4. Pipe Cutters
28
5. Weather Shelter
28
Electrofusion Jointing Method
28
Preparation of Pipe Ends
28
Jointing Procedure
29
Electrofusion Indicator Pins
31
Maintenance, Servicing and Calibration
31
Records
31
1. Job Supervision
31
2. Equipment Servicing and Calibration
31
3. Training
31
Electrofusion Saddle Jointing
32
Equipment
32
Preparation
33
Jointing Procedure
33
Top Load Electrofusion Branch Saddle Jointing
36
Maintenance, Servicing and Calibration
37
Records
37
1. Job Supervision
37
2. Equipment Servicing and Calibration
37
3. Training
37
Quality Assurance
37
Management Responsibility
38
1. Customer Focus
38
2. Planning
38
3. Responsibility, Authority and Communication
38
Control of Documents
38
1. Purchasing
38
2. Fusion Jointing Control
38
4. Corrective Action
38
5. Preservation of Product
38
6. Control of Records
38
7. Competence, Awareness and Training
39
Qenos Technical Guides
3
FOI Document #6
4(
7 PIPE AND TUBING EXTRUSION
APPENDIX 1 — RECORD SHEETS
40
APPENDIX 2 — PIPE EXTRUSION TROUBLESHOOTING GUIDE
41
BIBLIOGRAPHY/FURTHER READING
43
4
Qenos Technical Guides
FOI Document
4.#6
PIPE AND TUBING EXTRUSION
INTRODUCTION
Alkadyne polyethylene grades are used for the extrusion
of pipe. The application areas in which Alkadyne pipe resin
is typically used include:
• Mining for conveyance of corrosive and abrasive
slurries and tailings
• Water management projects such as large scale
irrigation for agriculture
• Residential water distribution
• Civil work such as sewers
.111 • Residential and industrial gas distribution
• Gas and water management in Coal Seam Gas
S•, extraction
• Management of industrial fluids
• Drainage
• Rural applications such as management of water
on farms, etc.
Disclaimer
All information contained in this publication and any further information, advice, recommendation or assistance given by Qenos either orally or
in writing in relation to the contents of this publication is given in good faith and is believed by Qenos to be as accurate and up-to-date as possible.
The information is offered solely for your information and is not all-inclusive. The user should conduct its own investigations and satisfy itself as to
whether the information is relevant to the user's requirements. The user should not rely upon the information in any way. The information shall not
be construed as representations of any outcome. Qenos expressly disclaims liability for any loss, damage, or injury (including any loss arising out of
negligence) directly or indirectly suffered or incurred as a result of or related to anyone using or relying on any of the information, except to the extent
Qenos is unable to exclude such liability under any relevant legislation.
Freedom from patent rights must not be assumed,
Qenos Technical Guides
5
FOI Document #6
7 PIPE AND TUBING EXTRUSION
INTRODUCTION
Alkadyne polyethylene grades (Table 1) are used for the
extrusion of pipe. The application areas in which Alkadyne
pipe resin is typically used include:
• Mining for conveyance of corrosive and abrasive
slurries and tailings
of PE-HD pipes, such as weldability, flexibility, chemical
resistance and abrasion resistance, PE 100 pipes also
bring marked improvements in important properties such
as creep strength, notch resistance and resistance to rapid
crack propagation.
PIPE APPLICATION REQUIREMENTS
• Water management projects such as large scale
irrigation for agriculture
• Residential water distribution
• Civil work such as sewers
• Residential and industrial gas distribution
0 • Gas and water management in Coal Seam Gas extraction
• Management of industrial fluids
• Drainage
• Rural applications such as management of water
on farms, etc.
Pipe materials have high strength and exceptionally
high toughness. At present PE 100 is the highest
classification for polyethylene resins and compounds from
which to make pressure pipe. This means that in addition
to retaining the generally acknowledged good properties
The operating pressures for pipe systems could be
as high as 2.5 MPa (25 bar) for example in the
transportation of water. For gas applications the pressure
is usually contained below 1.0 MPa (10 bar). The ability
of the pipe to withstand sustained pressure is important
and dimensions and pressure ratings for pipe made from
polyethylene are specified by relevant standards. A very
high resistance to cracking is required, because of the
wide range of environments and installation techniques
that can be encountered in the field. The pipe must have
excellent weathering resistance because of extended
outdoor exposure.
Specifications for polyethylene resins to be used in pipes
for the transportation of fluids under pressure are outlined
in relevant standards.
ALKADYNE GRADE SELECTION FOR PIPE
Table 1: Alkadyne Pipe Extrusion Grades
Grade
Melt Index
@ 190°C, 5kg
(g/10min)
Density
(g/crre)
HDF193B
0.3
0.961
High Density black PE100 Type resin certified to AS/NZS 4131, for use in
pressure pipes and fittings. Excellent low sag properties and throughput,
suitable for the majority of PE100 pipe dimensions.
HDF193N
0.3
0.952
High Density natural resin designed for extrusion into a full range of
non-standards pipe products and as a base for PE100 Type striping and
jacket compounds. HDF193N is not UV stabilised.
HDF145B
0.2
0.961
High Density black PE100 Type resin certified to AS/NZS 4131, for
use in pressure pipes and fittings. Exceptional low sag properties and
throughput, suitable for the most challenging pipe dimensions.
MD0898
0.7
0.952
Medium Density black PE8OB Type resin certified to AS/NZS 4131 for
use in pressure pipes and fittings.
MD0592
0.6
0.942
Medium Density natural resin designed for extrusion into a full range
of non-standards pipe products and as a base for PE80Type striping
and jacket compounds. MD0592 is not UV stabilised.
MDF169
1.0
0.943
Medium Density natural high molecular weight resin designed for
extrusion into a full range of non-standards pipe products. MDF169
is not UV stabilised.
LL0228
1.7*
0.923
Linear Low Density resin for use in pipe extrusion applications such as
trickle irrigation. LL0228 is not UV stabilised.
Application
* LL0228 @ 190°C, 2.16 kg. Melt Index according to ASTM 01238. Density accodring to ASTM D1505.
6
Qenos Technical Guides
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PIPE AND TUBING EXTRUSION 7
PIPE EXTRUSION TECHNOLOGY
CLASSIFICATION OF POLYETHYLENE PIPE
AND PIPE COMPOUNDS
Specifications for polyethylene compounds for use
in pressure pipes and pipes for pressure applications
in Australia are covered by two Australian Standards:
• AS/NZS 4131 "Polyethylene (PE) compounds for
pressure pipes and fittings"
• AS/NZS 4130 "Polyethylene (PE) pipes for pressure
applications"
The maximum allowable working pressure (and therefore
class) of the pipe at 20°C is determined by:
O
A pipe extrusion line consists of a number of pieces of
equipment. An extruder converts the polyethylene raw
material to a continuous tubular melt by extrusion through
an annular die. The molten pipe then proceeds through a
sizing or calibration device (which fixes its dimensions) to
a cooling trough. After being cooled, the pipe passes via a
haul-off to handling equipment for cutting into final lengths
or coiling. Printing devices may also be inserted into the
line to mark the extruded pipes with specific details.
A portion of a pipe extrusion line is shown in Figure 1.
• The type of compound used to make the pipe, and
• The dimensions of the pipe
Polyethylene compounds for pipe extrusion are designated
by the material type (PE) and an appropriate level of
Minimum Required Strength (MRS), details of which are
given in Table 2.
Table 2: MRS and Hydrostatic Design Stress
Requirements for PE 100 and PE 80 Compounds
C
Designation
Minimum Required
Strength (MRS)
(MPa)
Hydrostatic
Design Stress
(M Pa)
PE/MRS100
10.0
8.0
Granule Pre-treatment
PE/MRS80
8.0
6.3
Polyethylene is a hydrophobic material. However, for
polyethylene compounds that contain carbon black
that is hygroscopic in nature, problems can arise if the
moisture content of black polyethylene compound reaches
> 0.03 w/w%. During extrusion, moisture could cause
formation of voids in pipe wall and rough pipe surface.
The value of the minimum required strength is based on
the long-term hydrostatic stress in the pressure pipe when
extrapolated to a 50-year life at 20°C. The hydrostatic
design stress is arrived at by applying minimum safety
factor of 1.25 to the value of MRS. Reference should
be made to the data sheets for Alkadyne pipe grades for
details of their conformance to these requirements.
Figure 1: Illustration of a Pipe Extrusion Line
For each of the above designations, there are several
pressure classes with different wall thicknesses for each
nominal pipe diameter.
Figure 2: Photograph illustrating a Pipe with Voids
and a Rough Pipe Surface due to Excessive Moisture
in the Polymer Compound
Qenos Technical Guides
7
FOI Document #6
7 PIPE AND TUBING EXTRUSION
Such problems can be overcome by drying the polymer
granules in a hopper dryer at 70 - 90°C for 1.5 - 2 hours
immediately before feeding them into the extruder. The
duration of drying and the drying temperature should be
such that the moisture content is reduced to < 0.02 w/w%.
Solid ch
Main llighaln"\
Discharge come
DarrW_C_OgO
Extruder
For processing HDPE and MDPE into pipes, single screw
extruders are used. To achieve the high throughput
required for pipe production, high-speed extruders with
forced-conveying feed systems have been developed and
widely used throughout the industry (see Figure 3).
feed zono,
N. •
ZL491
Leading sticia
Trailing edge
Solid bed Melt reservoir
Figure 4: Schematic of a Barrier Flighted Screw
incorporating a Pin Mixer
Figure 3: Illustration of a Single Screw Extruder
with a Spiral Grooved Feed Bush used for High Polymer
Throughput
These extruders have a cooled, grooved feed bushing
which is thermally insulated from the extruder barrel. As a
result, the conveying efficiency of the pelleted feedstock is
greatly enhanced achieving higher extruder throughput. For
optimal operation of a grooved bush system, it is required
to keep the bush cold to prevent melting of the pellets and
fouling of grooves. In order to ensure effectiveness of the
grooved zone, these systems are cooled with a high flow
of chilled water (e.g. water flows of -10 L/min and water
temperature of approximately 10-20°C).
Recent developments in screw design have seen the
creation of barrier screws with enhanced melting capability
through the incorporation of a second spiral flight that
separates the polymer melt from the unmelted product
(see Figure 4).
In addition to the barrier screw, mixing elements are
generally used at the melt delivery end of the screw
to assist with homogenisation of the polymer melt
(see Figure 5).
8
Figure 5: Photos Illustrating some more Commonly
Employed Mixing Sections Located at the Melt Delivery
End of the Screw
The typical screw length used in modern pipe extruders
is generally around 30 LID (e.g. screw length is described
as a ratio of length divided by the screw diameter that
is measured at the flight). The newest generation high
throughput pipe line extruders have even higher screw
lengths of 40 L/D.
For example, a 90 mm well designed grooved feed
extruder, would operate at an output of close to
1,000 kg/hr and some advanced extruders may achieve
an output of 1,500 kg/hr.
Qenos Technical Guides
FOI Document #6
PIPE AND TUBING EXTRUSION 7
Table 3 shows expected specific screw output ranges
(expressed as kg/hr/rpm) of pipe extruders versus screw
diameter for high-speed-extruders with forced-conveying
feed sections. Advanced extruders will have outputs close
to the maximum of the designated output specification.
Table 3: LDPE and HDPE Specific Screw Output Data
Versus Screw Diameter
Screw diameter
mm
Specific output [kg/hr/rpm]
45
0.4 - 0.6
0.5 - 0.8
0.9 - 1.2
1.2 - 1.7
75
C 60
1.8 - 2.4
2.5 - 3.0
90
3.0 - 4.0
4.0 - 5.0
120
6.0 - 8.0
8.0 - 11
150
10 - 13
12 - 16
The economics of a pipe production plant will depend on
the following:
• The range of pipe sizes - e.g. diameter sizes
• The length of pipe runs - e.g. producing pipe of a set
dimension
High production extruder throughput has resulted in the
polymer experiencing low residence times in the extruder.
This lack of residence time can lead to concerns about
melt homogeneity and whether an even temperature
distribution has been achieved throughout the melt.
Modern pipe resin grades also have high melt viscosity
and elasticity that are required for the strength of the final
product, as well as for the ability to make large and thick
walled pipes within dimensional tolerances respectively.
These polymer features make the extrusion line die
absolutely essential for the successful manufacture of
pipe, especially with respect to its capacity to even up any
melt inhomogeneity and shape it into the pipe without the
generation of weld lines or any other memory effects which
could potentially compromise the strength or appearance
of the final product.
One of the established die designs is a "Spiral Mandrel".
The wide acceptance of this die has seen it incorporated
into many new pipe production line designs. This die design
has an excellent capability to homogenise melt and shape
it into pipe without generating any imperfections which
could compromise the final quality or integrity of the pipe
(see Figures 7 and 8).
• The available length of the cooling unit in the production
building
Bearing this in mind, increasing plant production capacity
might not be as straight forward as installing larger and
higher throughput extruders.
Pipe Dies
Today, manufacturers of pipe extrusion lines supply pipe dies
(see Figure 6) which they have developed themselves but
which are essentially based on a common design principle.
•
1 adapter
•
7 die housing
•
•
2 spiral distributor
•
8 holding plate
3 distributor housing
•
9 intermediate plate
•
4 rupture disk
•
10 centering
•
5 distributor heater
6 feed plate
•
•
11 die
•
12 mandrel
Figure 6: Photograph of a Pipe Die
Figure 7: Schematic Diagram Detailing the Components
of a Spiral Mandrel Die
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7 PIPE AND TUBING EXTRUSION
These concerns are associated with potential of building
up excessive internal pressure within the pipe and leading
to an uncontrolled rupture including release of the floating
plug. Vacuum sizing technology enables quick starting up
of an extrusion line. In addition, the melt emerging from
the die can be drawn down to obtain a range of final pipe
diameters so that it is possible to produce at least two
standard pipe sizes with a single die/calibrator combination.
Figure 8: A Spiral Distributor and its Operating Principle
for Melt Homogenisation
Another die design which has found wide approval and
use in pipe manufacture, for its performance, is the
Lattice-Basket type die. This design results in relatively low
extrusion melt pressure and consequently relatively low
melt temperature, both favourable for high extruder output
(see Figure 9).
The pipe is shaped by a slotted sizing sleeve commonly
referred to as a "calibrator". The calibrator is placed at
the entrance of the first vacuum tank and it is the first
downstream piece of line that the polymer melt sees
after having exited the die. Calibrators are usually made
from non-ferrous metal for rapid removal of heat (see
Figures 10 and 11). A film of water is fed to the inlet
of the calibrator to enable rapid cooling (e.g. below the
cyrstallisation temperature of the polymer) to solidify
the external pipe layer in order to pull the pipe into the
calibrator without tearing the molten tube apart. Water also
acts as a lubricant to reduce frictional forces on the pipe's
surface whilst it is being pulled through the calibrator. The
vacuum tank, in which the calibrator is placed, applies a
vacuum which pulls the still hot, malleable tube against the
wall of the calibrator, thereby setting the outer pipe
diameter to ensure conformance to the pipe's dimensional
specification. The vacuum is operated at about 0.05 MPa,
absolute pressure, which could vary depending on the pipe
dimensions. The calibrator is usually 3 - 5% larger than the
required final outer pipe diameter to provide for shrinkage
which takes place during pipe cooling.
Figure 9: A Lattice-Basket Die and the Basket Part
of the Die
Sizing and Cooling
In the state-of-the-art pipe manufacturing lines produced
today, vacuum tank sizing is the predominant method
used to shape the pipe from the melt. This includes the
manufacture of the very largest pipes that have dimensions
of 2000 mm. Unlike vacuum sizing, the internal pressure
sizing method, where a positive pressure is built up
within the pipe through the use of a floating plug, has
been rapidly phased out due to safety concerns.
10
Figure 10: Sizing Sleeve for Vacuum-tank Sizing
Qenos Technical Guides
FOI Document #6
'39
PIPE AND TUBING EXTRUSION 7
Using these assumed temperatures, the total cooling-zone
length can be calculated as follows:
L
= Lspec. (m)
where
Lspec = Specific cooling-zone length (m.hr/kg)
Q
= output (kg/hr)
Lspec relative to the pipe dimension is outlined in Table 4
below:
Table 4: Lspec Relative to the Pipe Dimension
(
Figure 11: Vacuum Tanks for Sizing Pipes up to
1,400 mm in Diameter
Downstream of the lst vacuum tank there could be
another vacuum tank and certainly more cooling tanks
to ensure that the pipe completely solidifies by the time it
gets to the saw (see Figure 12). The additional cooling is
important to achieving the final pipe dimensions within the
desired tolerances.
Pipe SDR*
Lspec for HDPE
41
33
26
17.6
11
7.4
0.016
0.02
0.024
0.036
0.06
0.08
*SDR = Standard Dimension Ratio; a nominal ratio of the pipe outside
diameter to its wall thickness
Downstream Equipment
Downstream equipment covers all other plant units
besides the extruder, die, sizing and cooling systems
(see Figure 13). Most pipe manufacturing lines will have:
• Ultrasonic Thickness Meter - that continuously
measures the wall thickness around the circumference
of the pipe
• Caterpillar Haul Off Unit - with concentrically arranged
caterpillars held under pneumatic pressure against the
pipe to transmit the haul-off forces. For start-ups, the
haul-off unit can be switched to operate in the reverse
to enable a pipe to be run back through the cooling and
sizing systems to the point where the melt exits from the
pipe die. There the pipe can be welded to the extrudate.
• Marking Unit - where the pipe is marked with standard
specifications
• Automatically Adjustable Saw - mounted on a table
cuts the pipe into the desired lengths
Figure 12: Photographs of Spray Water Bath
• Coiling Unit - where smaller diameter pipes can be
wound into coils or onto reels up to the appreciable
pipe size of 250 mm pipe diameter
The length of the cooling zone is dependent on the
output and the given dimensions of the pipe. The total
length (L) of the required cooling zone, can be calculated
on the assumption that a molten polymer extrudate, at
a temperature of -220°C, has to be cooled with water to
an external pipe temperature of -20°C, at which point the
internal surface temperature of the pipe is a maximum
of 85°C.
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7 PIPE AND TUBING EXTRUSION
Automatic
parting saw
— Multi-track
take-off machine
— Raw material
feed hopper
Spray cooling
system
— Die head
assembly
— Raw
material
dryer
Printers
High pressure
pump, filter and
control valves
Bundling jig
— Sizing sleeve
(brass)
— Extruder and screw
with zone healing
— Motor gear
box assembly
Figure 13: Schematic of a Pipe Extrusion Line showing Haul Off and Automatic Pipe Cutter
12
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FOI Document #6
32
PIPE AND TUBING EXTRUSION 7
Process Control
In new pipe production lines, process control computers
are used to automate production.
To produce pipe in the required dimensions, the relevant
operating data is entered, for example:
• Required throughput
• Pipe dimensions
• Screw speed
• Haul-off rate
The set-point values and permissible deviations are suitably
fed-back to the controller for process data monitoring.
In pipe manufacture, material costs represent a substantial
proportion of the overall costs of production. It is therefore
advisable to use computerised process control for optimum
production of pipes with the least possible waste of
material and the best possible thickness uniformity around
the pipe circumference. Figure 14 shows a schematic
diagram of a computerized process control system for a
pipe production line.
pipe dimensions
output
1 operating data
ni
process computer
)
pipe haul-off
speed
weigh
feed er
ultrasonic
wall thickness
measurement
MECHANICAL PERFORMANCE OF
POLYETHYLENE PIPE GRADES
Short-term Behaviour at Low Deformation Rates
A typical stress/strain curve for HDPE pipe (PE 100 type
pipe compound) is shown in Figure 15.
The tensile test reveals the characteristic stress/strain
curve for cold stretching of an unreinforced, partially
crystalline polymer. Initially, tensile stress increases up to
the yield point. This is followed by spontaneous neckingdown of the test specimen accompanied by an apparent
decline in tensile stress, since the stress is related to the
initial cross section and not to the necked-down cross
section at the yield point. When the necking-down has
progressed along the entire length of the test specimen
to the clamps, tensile stress increases again as a result
of material strengthening due to macromolecular network
straining and orienting until the breaking point is reached
(ultimate tensile strength, elongation at break).
Because of the special deformation characteristics of
polyolefins, it is advisable to use an extensiometer to
determine elongation at break. Assessment is only
possible when the necking-down has progressed beyond
the measuring zone at each end. A polyolefin only retains
its useful application properties up to the yield point and
so it is better to dispense entirely with measurement of
ultimate tensile strength and elongation at break.
pipe die
with centringdevice
Figure 14: Computerized Process Control System for
a Pipe Production Line
The most commonly employed control system operates on
the basis of interaction between the following options:
• Weigh Feeder - the extruder is equipped with a
weigh feeder. Weighed granule portions are fed to the
extruder operating at required speed to achieve set
off-take of the weighted granulate feed. Any deviation
from the set output resulting from the constant weight
feed is compensated for by speed adjustment of the
extruder screw via the control system.
Figure 15: Typical Stress/Strain Curves for HDPE
Measured in a Tensile Test on Test Specimen Prepared
from Compression Moulded Sheet; Test Temperature
23°C, Testing Rate 50 mm/min
• Haul Off Control - the haul-off is set to a speed calculated
from the specified output and the required weight per
metre of the pipe. Pipe wall thickness is measured around
the circumference with an ultrasonic wall thickness meter.
Qenos Technical Guides
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FOI Document #6
7 PIPE AND TUBING EXTRUSION
The effect of temperature on the yield stress, ultimate
tensile strength and elongation at break of a typical HDPE
pipe grade is shown in Figure 16.
-;-; 10,000
;12
co
In the creep test, the increase in deformation with time
of a specimen held under a constant stress is measured
and from this, the creep modulus is calculated.
Measurement can be carried out in a flexural creep test
or a tensile creep test. It should be noted that the creep
modulus is dependent on the level of stress as well as on
temperature and time. Typical creep curves are shown in
Figures 17 and 18.
Er
tow
Cs
cy)
0
LT)
Creep Test
100
Ys
-20
0
20
ao
Temperature (°C)
—
Yield Stress, Ys (k1Pa)
—
Elongation at Break, Er (*A)
Is
60
BO
—Ultimate Tensile Strength. Ts (tvIPa)
Figure 16: Yield Stress, Ultimate Tensile Strength and
Elongation at Break of HDPE as Functions of Temperature
Figure 17: Typical Tensile Creep Modulus Curves of HDPE
Determined at 23°C
Long-term Behaviour
High density polyethylene is a viscoelastic material. Like
all thermoplastics, it exhibits the property known as creep,
i.e. over a period of time it undergoes deformation even at
room temperature and under relatively low stress. After
removal of stress, a moulding more or less regains its
original shape, depending on the time under stress and the
magnitude of the stress. The recoverable deformation is
known as elastic deformation whereas the permanent
deformation is called plastic deformation.
It should be remembered that the mechanical properties of
a plastic are dependent on the three important parameters
of time, temperature and stress.
In design calculations for moulded components, the
mechanical property values (which in most cases are
determined by long-term tests) must be divided by a
safety factor.
Creep Behaviour Under Uniaxial Stress
A distinction is made between creep and relaxation tests.
14
Figure 18: Typical Tensile Creep Modulus Curves of
HDPE, Determined at 40°C
Similar tests have been carried out to determine creep
moduli under compressive stress. Taking scatter into
account, these gave approximately the same results as
those for tensile stress.
The creep modulus can be used in design calculations for
moulded parts which are to be exposed to constant stress
over an extended period of time.
Qenos Technical Guides
FOI Document #6
PIPE AND TUBING EXTRUSION 7
Relaxation Test
QUALITY TESTING OF POLYETHYLENE PIPE
In the relaxation test, the stress decay with time of a
specimen held under constant deformation is measured
and from this, the relaxation modulus is calculated.
PE 100: A Package of Good Properties
600
E
• 500
-2
c = 0.5
-0 400
7
-5
-8
2
C
1
300
E = 2%
200
• High resistance to Slow Crack Growth (SCG)
• High resistance to Rapid Crack Propagation (RCP)
-o
w 100
104
10°
101
102
103
Stress Time (Hrs)
Figure 19: Typical Relaxation Modulus Curves of HDPE,
Determined at 23°C
It should be noted that the relaxation modulus is
dependent on the level of strain as well as on temperature
and time.
The relaxation modulus (see Figure 19) can be used in
design calculations for moulded parts that are to be
exposed to constant strain or compression over an extended
period of time.
C
The designation PE 100 indicates that a PE-HD material
has been assigned to performance class MRS 10 where
MRS stands for Minimum Required Stress. The minimum
creep strength is thus 10 MPa stress in the pipe wall at
20°C and 50 years. However creep strength alone does
not determine assignment to material class 100 but rather
a whole range of improved properties resulting from the
much improved toughness of these materials, the most
notable being:
Behaviour at High Deformation Rates
Information on the toughness characteristics of polymer
materials at high deformation rates is provided by flexural
and tensile impact strength tests. The results of impact
strength tests (values for impact strength, notched impact
strength and tensile impact strength) are considerably
influenced by the conditions under which the test specimen
is prepared. Injection moulded test specimens because of
their rapid cooling rate are less crystalline when solid and
therefore more impact resistant than those prepared from
compression moulded sheet. The orientation produced by
injection moulding also has an effect.
Qenos Technical Guides
Hydrostatic Pressure Tests
Undoubtedly the most important property of plastic pipes
is their hydrostatic strength behaviour under internal
pressure or "Creep Strength". This is what determines the
service life expectancy of the pipe under internal pressure.
The equivalent stress (resulting from the action of the applied
pressure within the pipe) corresponds in practice to the hoop
stress acting on the pipe internal surface. Knowledge of the
permissible stress for the material concerned forms the
basis for designing a pipe under a given internal pressure
using the calculation formula for pressure vessels.
The pressure to be used in the test is calculated from the
equation below, knowing the dimensions of the pipe and
the required hoop stress.
P=
2ST
Dm min. +
where:
P = maximum working pressure at 20°C (MPa)
S = hoop stress of hydrostatic design stress at 20°C (MPa)
T = minimum wall thickness (mm)
Dm m in. = minimum mean inside diameter (mm)
Creep Test Under Internal Pressure
The stress that leads to rupture in plastic pipes depends
on the time under stress and the temperature of the test.
Creep behaviour has been studied in long-term tests over
many years, in some cases, since 1956 (see Figure 20).
ISO 9080 standard "Plastics piping and ducting systems
—Determination of the long-term hydrostatic strength of
thermoplastics materials in pipe form by extrapolation"
sets out rules for the determination of the long-term
hydrostatic strength of polyethylene pipes.
15
FOI Document #6
7 PIPE AND TUBING EXTRUSION
The hydrostatic tests that are carried out on pipe sections
under internal pressure take into account the effect of the
multi-axial strain occurring in practice. The pipes are filled
with water and suspended in a temperature-controlled
environment such as a water bath (see Figure 22).
Figure 20: The First Creep Rupture Test Started In
1956 In HOECHST (today known As Lyondell BaseII)
Laboratory, Frankfurt
The same test rig, and "original" pipes are still in operation
today (see Figure 21). On 18th October 2006, two pipe
specimens on this "historical" test stand finally confirmed
the predicted service of 50 years.
Figure 22: Extensive Hydrostatic Pipe Testing at Qenos
Technical Centre
Figure 21: The First Creep Rupture Test Started in 1956
in HOECHST (today known as Lyondell Basel!) Laboratory,
Frankfurt, is still on test
16
Qenos Technical Guides
FOI Document #6
PS
PIPE AND TUBING EXTRUSION 7
Pipe pressure Curve and Service Life
Extrapolation
The results of these tests are plotted on a log-log scale.
Test stress is plotted against endurance time. After
sufficiently long testing times, the typical pipe curve
obtained from this plot shows three different regions or
stages (see Figure 23).
Hoop Stress/Application Pressure
brittle failure a < ay
Slow crack growth
6111111111111 w
I: Ductile Failure . a>
Figure 24: Pipe Failed in Ductile Mode
Ductile failure indicates ultimate pressure bearing
capability of the pipe. The flat branch therefore marks the
stress limit for ductile failure.
ay
Ill
Temperature VC)
Ill: brittle failure:
- Stabilizer migration
- Oxidation and degradation
of polymer
▪ 20
O go
-
Application Time
Weembeeee,,ieeiteta,
to,
Figure 23: Representation of Pipe Curve According to the
3-stage Model (Illustration by Studsvik Material AB now
known as Exova)
r
;1-40
es•
e.
Time to failure (Hrs)
Starting with short endurance times, a flat, straight
branch can be seen which is followed by a straight, steep
branch. With the PE 100 grades currently used, this steep
branch does not begin for 10 000 hours, even at elevated
temperature (e.g. 80°C). After very long endurance times,
a vertical, stress-independent branch of the curve could
be expected to follow for testing at 80°C, effectively
indicating resin has degraded due to long exposure to
high temperature.
Each of the three curve stages is associated with three
different failure mechanisms. In the flat stage of the
pressure curves at 20°C and 80°C represented on
Figure 25, only ductile fractures are observed. Ductile
type failure shows a visible deformation on the pipe in
the failure region. Figure 24 shows a section of pipe that
has failed in a ductile mode.
Figure 25: Qualitative Interpretation of Pipe Curve as
Generated on PE 80 Pipe Grade. Testing was According
to ISO 9080.
For the long-term properties of a pipe material, the position
of the steep branch is crucial (e.g. in practice the steeper
branch in the pressure test is referred to as a "knee"). It is
determined by the resistance of the material to slow crack
propagation. This material property, also referred to as
brittle fracture resistance, determines the service life of the
pipeline. In other words pipelines are designed to operate in
a "ductile" failure regime. The inflection point (the transition
between the flat and steep branches) can be observed, if at
all, only at high temperature and after very long endurance
times. This position denotes the transition from "ductile" to
"brittle" type behaviour of pipe under pressure.
Pipe that has failed in a brittle mode doesn't show visible
ductility in the failure region (see Figure 26).
Qenos Technical Guides
17
FOI Document #6
211
7 PIPE AND TUBING EXTRUSION
TEMPERATURE RE-RATING OF PE PIPES
The Maximum Allowable Operating Pressure (MAOP)
of a polyethylene (PE) pipe system is influenced by the
temperature of the pipe wall. The nominal pressure rating
(PN) assigned to an AS/NZS 4130 PE pipe equates to
performance at 20°C, i.e. a PN16 pipe is capable of
withstanding a MAOP of 160 m head (or 1.6 MPa or 16 bar
pressure) when operating continuously at 20°C. However,
as the temperature of the pipe wall increases, the MAOP of
the pipe is reduced progressively, in other words the pipe
system is re-rated with increasing temperature.
The guidance provided in this document is based on
typical PE compounds used in Australia and New Zealand
to manufacture AS/NZS 4130 PE pipe and listed in PIPA
Guideline POP004, Polyethylene Pipe Compounds.
Figure 26: Pipe Failed in Brittle Mode
Modern pipe grades such as PE 100 should not show
"brittle" like pipe failures in hydrostatic tests, even at 80°C,
within the required one year testing time (see Figure 27).
Temper awe
a 20
Note: These guidelines apply to pipe used for the
conveyance of water. Where other incompressible fluids are
being considered, the designer must assess the effect of
the fluid on the PE pipe system at the operating temperature.
For example internal fluids such as aggressive condensates
when absorbed may have the effect of reducing the material
strength upon which design stress is based.
60
The rerating factors in this guideline are expressed in
terms of metre head of water and are not for use with
compressed air or gas applications.
:
(I)
LTHS
- LPL
Time to failure (firs)
Figure 27: Creep Rupture Curve for Qenos PE 100 Grade
Alkadyne HDF193B. Testing was According to ISO 9080.
When a PE piping system is to operate at a continuous
temperature higher than "designated standard"
temperature of 20°C, ISO 9080 analysis could be used
to demonstrate capability of the pipe network in terms
of extrapolated values for application stress and life time.
Actual service life time of the PE pipe network will depend
on application conditions and ISO 9080 extrapolation
should not be used to infer actual service life time of the
PE network.
The following information details how to determine
the temperature of the pipe wall and, then using Table 5
and 6, determine the de-rated MAOP value for the system.
These recommendations are not to be taken as detailed
specifications.
Determining the Temperature of the Pipe Wall
The pressure rating of PE pressure pipe systems is based
on the temperature of the pipe wall, which may be
determined from either:
a. An assumption of a constant pipe wall temperature
typical for continuous service at a set temperature,
e.g. cold water service; or
b. The determination of an average service temperature
where temperature variations are likely to occur in a
predictable pattern (refer below), e.g. in cavity walls or
roof spaces; or
c. The maximum service temperature less 10°C for
installations where large unpredictable temperature
variations occur up to a maximum of 80°C, e.g. aboveground installations such as irrigation systems.
18
Qenos Technical Guides
FOI Document #6
v.&
PIPE AND TUBING EXTRUSION 7
Predictable Temperature Variations
Tm = Ti
Li+ T2L2 + "' + Tni—n
where:
For installations where predictable temperature variations
occur, the average material temperature is determined
from Item (d) or Item (e) as follows:
T„ = average pipe material temperature for the period
of time under consideration, in °C
d. Across the wall of the pipe — the material temperature
taken as the mean of the internal and external pipe
surface temperatures, where a temperature differential
exists between the fluid in the pipe and the external
environmental.
(
Tn = average pipe material temperature for a proportion
of pipe life, in °C
1_, = proportion of life spent at temperature Tr,
Determining the MAOP Value
The pressure and temperature condition, where flow is
stopped for prolonged periods, should also be checked.
In this event, fluid temperature and outside temperature
may equalise.
Once the temperature of the pipe wall has been
determined using any one of the methods (a), (b) or (c)
above, the following tables can be used to determine the
re-rated MAOP for the PE pipe system.
e. With respect to time — the average temperature may be
considered as the weighted average of temperatures for
the proportion of time spent at each temperature under
operational pressures; it is calculated with the equation:
Table 5 nominates the corresponding MAOP for a given
temperature for PE 80B material. Table 6 provides the
same information for PE 100 material.
Table 5: Maximum Allowable Operating Pressure - PE 80
Temp
(°C)
20
Min Life
(yr)
100
Design
Factor
PN 3.2
PN 4
PN 6.3
PN 8
PN 10
PN 12.5
PN 16
PN 20
1.0
32
40
64
80
102
128
160
200
25
1.0
32
40
64
80
102
128
160
200
30
1.2
27
33
53
67
85
107
133
167
35
1.3
25
31
49
62
78
98
123
154
40
1.3
25
31
49
62
78
99
123
154
1.4
23
29
46
57
73
91
114
143
50
36
1.6
20
25
40
50
63
80
100
125
55
24
1.7
19
24
38
47
60
75
94
118
60
12
1.8
18
22
36
44
56
71
89
111
2.4
13
17
27
33
42
53
67
83
45
80
1
Table 6: Maximum Allowable Operating Pressure - PE 100
Temp
(°C)
Min Life
(yr)
Design
Factor
20
100
1.0
25
100
1.1
30
100
35
50
PN 4
PN 6.3
PN 8
PN 10
PN 12.5
PN 16
PN 20
PN25
SDR41
SDR26
SDR21
SDR17
SDR13.6
SDR11
SDR9
SDR7.4
40
64
80
100
127
160
200
250
36
58
73
91
115
145
182
227
1.1
36
58
73
91
115
145
182
227
1.2
33
53
67
83
106
133
167
208
40
50
1.2
33
53
67
83
106
133
167
208
45
35
1.3
31
49
62
77
99
123
154
192
50
22
1.4
29
46
57
71
91
114
143
179
55
15
1.4
29
46
57
71
91
114
143
179
60
7
1.5
27
43
53
67
85
107
133
167
80
1
2.0
20
32
40
50
63
80
100
125
Note: the minimum life periods may be considered to be the minimum potential service lives and represent the maximum extrapolated periods
permitted by the ISO 9080 extrapolation rules given the available test data.
Qenos Technical Guides
19
FOI Document #6
7 PIPE AND TUBING EXTRUSION
NOTCH RESISTANCE (SCG) OF PE PIPES
C,
Behind the phenomenon of creep strength and notch
resistance lays the process of slow crack propagation.
The brittle fracture observed is initiated by small defects
or notches in the pipe. An increase in temperature
accelerates this process. The fracture diagram (see Figure
23) shows a small crack running lengthwise along the pipe.
As a partially crystalline polymer, polyethylene reacts to
the stress concentration at the crack tip (notch root) by
forming a crazing zone. This crazing zone develops into a
fully propagating crack that leads to a "brittle" type failure.
Application stress, which could lead to craze initiation and
crack propagation, is of the magnitude that is observed for
the hoop stress the pipe experiences in operation due to
the presence of an applied operating pressure.
This pipe is then pressure creep-tested under the following
conditions:
• PE 100: 80°C; 4.6 MPa Hoop Stress; endurance time >
500 hrs
• The PE 100 materials pass this test without any problem
Therefore, it is widely accepted in the field that the most
application relevant pipe property is its resistance to slow
crack growth, in other words, its susceptibility to "brittle"
failure.
Notch Test
The notch test according to ISO DIS 13479 may be
regarded as a variant of the pressure creep test in which
crack propagation resistance is specially assessed. Unlike
the creep test under internal pressure, the failure point in
this test is predetermined by notching.
•
In this test, four notches are cut in the outer surface of
the pipe specimen in the longitudinal direction, each at
900 to the pipe circumference and with a defined geometry
(Vee angle 60 0 , notch depth = 20% of wall thickness).
See Figures 28 and 29 for details.
Slow Crack Growth
Notched Pipe test
Four notches equi-spaced around
the pipe circumference. The
ligament thickness is 0.78 to 0.82
times minimum specified wall
A
Figure 29: Pipes Notched and Assembled to be Tested
for Slow Crack Growth Property as per ISO 13479. Pipes
made from Qenos Pipe Grade Alkadyne HDF193B.
RESISTANCE TO RAPID CRACK PROPAGATION
(RCP) OF PE PIPES
By rapid crack propagation we mean the following
phenomenon: if a gas pipe during operation is damaged
by an external force (e.g. by construction machinery) or
by a stress-induced crack (e.g. in a defective weld) then,
under the action of internal pressure and hence of the
potential energy stored in the gas, the crack can spread
over an extended length at almost the speed of sound
(see Figure 30). In the case of PE 100, the range of
applications is widened to include higher operating
pressures; therefore pipe designers must be given highly
reliable assurances as to the resistance of the pipe
material to rapid crack propagation.
1,/
Position of minimum
wall thickness
Pipe end caps
Section AA
Figure 28: Illustration of Notched Pipe Test
20
Qenos Technical Guides
FOI Document #6
21+
PIPE AND TUBING EXTRUSION 7
closing moment
weaving crack
Figure 30: Example of Rapid Crack Propagation Fracture
in Pipe Which Shows the Actions of Residual Stresses on
the Cracked Pipe During RCP
S4 Test
Commonly employed testing methodology for RCP is
based on the ISO 13477 standard. It is known in industry
as the S4 test (small-scale, steady-state test). The S4 test
is carried out as follows: a weight with a knife attached
to the end is dropped onto a pipe of standardised length
and under a constant internal gas pressure near one of
its ends to produce a rapidly progressing axial crack.
The crack initiation process should damage the pipe as
little as possible. The term crack propagation is used if
the crack length, a, is greater than or equal to 4.7 dn
(4.7 times the nominal outside diameter). See Figures 31
and 32 for details.
A series of tests at 0°C but varying in testing pressure lead
to the determination of the critical pressure at which there
is a sharp transition from abrupt arrest of the initial crack
to continued, steady-state, crack propagation. This method
arrives at the "Critical Pressure" at which RCP occurs.
Crack propagation zone
> di,
I
>2
3
drop bolt
with wipe
test zone > 5 • di,
test specimen
diameter di,
!
111111,111.11111110611411-0-4 10 I
if
fro -co -lc PcLAI Vaor
buttress
limiting retainer ring
decompression
impact plate
Figure 31: Schematics of a Test Rig for the S4 Test
Qenos Technical Guides
Figure 32: Actual Test Rig for the S4 Test
Alternatively, tests can be carried out at the set pressure
but varying test temperatures to determine the "Critical
Temperature" at which RCP occurs (see Tables 7 and 8).
In designing a pipeline, to carry gas at high pressure or
at sub-zero temperatures the RCP property of pipe resin
needs to be considered and a safety factor must be taken
into account.
For gas pipelines made from Qenos Alkadyne PE 100
grades, the high RCP property ensures safe pipe line
operation at high operating pressures as well as sub-zero
temperatures.
21
FOI Document #6
7 PIPE AND TUBING EXTRUSION
Table 7: RCP Testing of PE 100 Pipe at a Fixed Pressure and Varying Temperature
Temperature
(°C)
Pressure
(MPa)
Crack Length
I (mm)
1
-5
0.5
120
1.1
Crack Arrest
2
-10
0.5
135
1.2
Crack Arrest
Pipe No.
Results
3
-15
0.5
165
1.5
Crack Arrest
4
-20
0.5
360
3.3
Crack Arrest
5
-25
0.5
300
2.7
Crack Arrest
The critical temperature Tc of the PE pipes (110 mm diameter) SDR11, Qenos grade Alkadyne HDF145B, at a pressure of
0.5 MPa, is lower than or equal at -25°C
0
Table 8: RCP Testing of PE 100 Pipe at a Fixed Temperature and Varying Pressure
Pressure
(MPa)
Crack Length a
(mm)
a/d„
Results
1
0.0
85
0.8
Initiation Test
Pipe No.
2
0.4
110
1.0
Crack Arrest
3
0.6
120
1.1
Crack Arrest
4
0.8
130
1.2
Crack Arrest
5
1.0
125
1.1
Crack Arrest
The critical pressure P
- c,S4 of the PE pipes (110 mm diameter) SDR11, Qenos grade Alkadyne HDF145B, at a temperature of
0°C, is higher than or equal to 1.0 MPa
Table 9: Collation of ISO to Australian Standards for Set Items, Equipment, Installation and Testing
C
International Standard
Subject Matter
Australian Standard
ISO 8085-2
Fittings
AS/NZS4129 Section 6
ISO 4437
Gas Pipe
AS/NZS4130
ISO 4427
Water Pipe
AS/NZS4130
ISO 12176-1
Equipment
Not applicable
ISO/TS 10839
Installation
AS/NZ52033, AS/NZS 4645
ISO 13593
Tensile Test
Not applicable
ISO 1167-1
Hydrostatic Pressure Test
AS/NZS 4130 Clause 10.1
ISO 1167-3
Hydrostatic Pressure Test
AS/NZS 4130 Clause 10.1
ISO 1167-4
Hydrostatic Pressure Test
AS/NZS 4130 Clause 10.1
ASTM F2634
High speed tensile test
Not applicable
22
Qenos Technical Guides
FOI Document #6
PIPE AND TUBING EXTRUSION 7
JOINING PE PIPES
Butt fusion jointing of PE pipes and fittings
Note: Information is based on POP 003 prepared by PIPA
(Polyolefin Industry Pipe Association) as a guide to the butt
fusion of polyethylene pipe using AS/NZS 4130 material as
a basis.
Relevant Standards
The butt fusion procedures and parameters are specified in
ISO 21307, Plastics pipes and Fittings - Butt Fusion Jointing
Procedures for Polyethylene (PE) Pipes and Fittings Used in
Construction of Gas and Water Distributions Systems.
ISO 21307 specifies three proven butt fusion jointing
procedures for pipes and fittings with a wall thickness
up to and including 70 mm, taking into consideration:
• The materials and components used
• The fusion jointing procedure and equipment
• The quality assessment of the completed joint
This standard also covers the weld procedure for activities
such as surface preparation, clamping, alignment and
cooling procedures.
Where ISO 21307 references other International
Standards, the equivalent Australian Standard is deemed
to apply. Where there is no equivalent Australian Standard
then the International Standard applies (see Table 9).
Jointing Procedures
Butt welding involves the heating of two pipe ends to fusion
temperature and then subsequently joining the two ends
by the application of force. However, a successful butt weld
requires the correct combination and sequence of the
welding parameters time, temperature and pressure.
• Dual pressure - low fusion jointing pressure
This method is used by the water industry in the UK, and in
Europe for pipes with a wall thickness greater than 20 mm.
These parameters are not commonly used in Australia.
• Single pressure - high fusion jointing pressure
This method has been used extensively in Northern
America. The weld interface pressure is approximately
three times the low pressure method and, as a
consequence, more of the molten material is extruded
from the weld zone, thereby enabling a reduced cooling
time. Extra attention is required to ensure that:
1. Welding machines have sufficient structural strength
and hydraulic capacity to achieve the high pressure
parameters in a safe manner. Confirmation should be
sought from the machinery manufacturer.
2. The welding operator is sufficiently experienced and
proficient with the parameters.
Where the pipe or fitting wall thickness exceeds 70 mm
welding parameters should be agreed between the asset
owner and the installer. Under these circumstances the
pipe and fitting supplier and the equipment supplier should
also be consulted.
Schematically all three welding procedures are outlined in
Figure 33 and Table 10 which show:
• Procedures are similar in overall approach, i.e. the seven
steps of fusion
• Primary differences are in applied pressure and
approach to cooling
• When properly performed, all methods result in
reliable joints
Initial Bead Up
0.517 Mpa
Various proven butt fusion methods with minor differences
have been in use in different countries for many years.
ISO 21307 contains three distinct fusion methods
described below for pipe and fittings with a wall thickness
up to and including 70 mm.
It is essential that the parameters specified for a given
method are followed. Do not mix and match parameters
from each method.
• Single pressure - low fusion jointing pressure
This method has been used by most European countries
and in Australia. The single pressure parameters specified
are very similar to those previously specified by PIPA.
Welders familiar with those parameters will adapt easily
to the ISO Single pressure - low fusion jointing method.
Qenos Technical Guides
Bead Roll Over
Cooling Time
0.15 Mpa
Heat Soak
• 0.025 Mpa
Heater Plate
removed
Time to achieve
Interface Fusion
Pressure
Time -
— Dual Pressure — European Single Pressure — USA Single High Pressure
Figure 33: Schematic Diagram of the Various Stages of
the Polymer Butt Welding Process
23
FOI Document #6
7 PIPE AND TUBING EXTRUSION
Table 10: Parameters Corresponding to the Three Butt Welding Processes
C
Butt Welding Parameter
Unit
Single Low
Pressure
Single High
Pressure
(If en > 20mm)
Heater pipe temperature
°C
200 to 245
200 to 230
225 to 240
P1
Bead up pressure
MPa
0.17 ± 0.02
0.52 ± 0.1
0.15 ± 0.02
Ti
Bead up time
Visual
First indication of melt everywhere around pipe.
(Approx. 1mm, maximum 6mm)
P2
Heat soak pressure
MPa
0 to drag pressure
0 to drag pressure
0 to drag pressure
T2
Heat soak time
Seconds
(11 ± 1)en
(11± 1)e
10e, + 60
Maximum bead size after 12
Mm
0.5 + 0.1e,
0.15en + 1
0.5 + 0.1en
T3
Maximum heater plate removal time
Seconds
0.1en + 4
0.1en + 8
14
Maximum time to achieving welding
pressure
Seconds
0.4en + 2
0.1en + 8
0.17 ± 0.02
0.52 ± 0.1
en + 3
0.43en
Dual Low Pressure
P3
Fusion jointing pressure
Seconds
T5
Cooling time
Minutes
T5a
Fusion jointing time
Seconds
10 ± 1
T5b
Minimum cooling time in machine
Minutes
See ISO 21307
0.15 ± 0.02
under reduced pressure
P4
Cooling cycle reduced pressure
MPa
16
Additional cooling time
Minutes
Electrofusion Jointing of PE Pipes and Fittings
0
Note: Information is based on POP 001 prepared by PIPA
(Polyolefin Industry Pipe Association) as a guide to the
electrofusion of polyethylene pipes and fittings complying
with Australian/New Zealand Standards AS/NZS 4130 and
AS/NZS 41291.
These guidelines set out the principal requirements for
equipment, jointing procedures, maintenance, servicing and
calibration of equipment, records and training for jointing by
socket electrofusion (EF) and saddle electrofusion.
0.025 ± 0.002
Additional cooling time out of the machine and before rough
handling or installation may be recommended, but in most cases
is not necessary
recommended for use with PE pipes SDR17 or lower
(i.e. increased wall thickness).
Pipes of different PE materials- PE 63, PE 80 and PE
100 can also be jointed successfully using electrofusion
sockets, provided that all components have adequate
nominal pressure rating for the operating conditions and
the PE materials comply with AS/NZS 4131.
The guidelines are also applicable to electrofusion fittings
that are available in the size range DN16 to DN800.
Development work is being undertaken for larger sized
electrofusion fittings.
Some manufacturers supply electrofusion fittings for
thinner pipes, down to SDR33 whereas others limit the
use of some saddle type fittings to SDR11 or thicker. These
limitations are usually detailed on the fitting body or on
the packaging. If in doubt, check with the supplier or
manufacturer, as unsatisfactory joints are likely to occur
if the fitting/pipe combination is incorrect.
To consistently make satisfactory joints it is important to
follow the jointing procedure with particular emphasis on
pipe surface preparation, avoidance of contamination, and
machine calibration, as well as temperature control.
It is recommended to refer to the supplier or
manufacturer of the electrofusion fittings for the
installation instructions, as the method may be
specific to the fitting geometry.
Pipes and fittings of different SDR can be joined together
by the electrofusion process, e.g. DN250 SDR11 pipe can
be successfully electrofused using a DN250 SDR17 fitting.
Electrofusion fittings for pressure applications are usually
Accurate record keeping and manual or automatic
electrofusion equipment that provides good control of
jointing conditions are essential.
1. EF fittings can be used with non-pressure drainage pipes made to
AS/NZS 4401 and AS/NZS 5065.
24
Qenos Technical Guides
FOI Document #6
pao
PIPE AND TUBING EXTRUSION 7
SDR Pipe to Fitting Fusion Compatibility
The following table provides recommendations of the fusion compatibility of PE pipe to PE electrofusion fittings
(see Table 11).
Table 11: SDR 11 Electrofusion Fittings
Electrofusion Fittings
SDR11
Electrofusion
Saddles SDR11
Branch Fittings
SDR11
PE Pipe SDR Rating
Pipe DN
11
17/17.6
11
17/17.6
16
+
-
-
-
20
+
25
+
-
32
+
40
+
50
+
63
+
75
+
-
90
+
110
-
-
-
11
17/17.6
-
-
-
-
-
+
-
+
-
-
-
+
+
-
+
+
+
+
+
+
+
+
+
+
+
125
+
+
+
+
+
+
140
+
+
+
+
+
+
160
+
+
+
+
+
+
180
+
+
+
+
+
+
200
+
+
+
+
+
+
225
+
+
+
+
+
+
250
+
+
+
+
+
+
280
+
+
+
+
+
+
315
+
+
+
+
+
+
355
+
+
+
+
+
+
400
+
+
+
+
+
+
450
+
+
+
+
+
+
500
+
+
+
+
+
+
560
+
+
+
+
+
+
630
+
+
+
+
+
+
where: + corresponds to suitable and - corresponds to unsuitable
Consultation with the fitting supplier or manufacturer is advised for confirmation of fusion compatibility.
Qenos Technical Guides
25
FOI Document #6
7 PIPE AND TUBING EXTRUSION
Electrofusion socket jointing
Electrofusion socket jointing incorporates an electrical
resistance element in the socket of the fitting which, when
connected to an appropriate power supply, melts and fuses
the materials of the pipe and fitting together.
The effectiveness of this technique depends on attention
to preparation of the jointing surfaces, in particular the
removal of the oxidised surface of the pipe over the socket
depth, ensuring the jointing surfaces are clean and free
from contamination, and that the assembly and clamping
instructions are correctly followed.
The pipe is prepared for jointing by removing a layer,
maximum of 0.2 mm for pipes up to DN25, 0.2 mm to
0.3 mm for pipes up to DN75 and 0.2 mm to 0.4 mm for
pipes larger than DN75. The minimum allowable outside
diameter of the prepared pipe is shown below (see
Table 12).
Table 12: DN of Pipe Versus Minimum Outside Diameter of Prepared Pipe
Minimum outside
diameter (OD)
of prepared pipe
(mm)
DN of Pipe
Minimum outside
diameter (OD)
of prepared pipe
(mm)
16
15.6
200
199.2
20
19.6
225
224.2
DN of Pipe
25
24.6
250
249.2
32
31.4
280
279.2
40
39.4
315
314.2
50
49.4
355
354.2
63
62.4
400
399.2
75
74.4
450
449.2
90
89.2
500
499.2
110
109.2
560
559.2
125
124.2
630
629.2
140
139.2
710
709.2
160
159.2
800
799.2
(1) 180
179.2
If entry of the pipe or fitting spigot into an electrofusion
coupling is still restricted after the oxidised layer has been
removed, the pipe can be scraped down to the permissible
minimum outside pipe diameter as in the above table. In
this case, the thickness removed may be greater than the
thickness stated above.
Pipe should also be checked for out-of-roundness (ovality).
Some coiled pipes may be too oval to fit into electrofusion
sockets and must be re-rounded with rounding tools or
clamps to enable sockets to be fitted.
The equipment and procedures described below relate
to fittings with centre stops. If fittings without centre stops
are used, the maximum insertion depth should be clearly
marked on the pipe ends after the pipe surface has been
prepared and cleaned prior to jointing.
26
Equipment
1. Control Box
The control box input supply should be from a nominal
240V generator suitable to drive inductive loads and phase
cut systems, commonly of about 5kVA capacity. Some
fitting suppliers may consider smaller capacity generators
acceptable for small diameter fittings. The nominal output
of the generator should be 240V ± 10%, between no load
and full load.
It should be noted that electrofusion control boxes
may generate considerable heat. Refer to the supplier
of the controller to ensure the box has an integrated
cooling system.
Qenos Technical Guides
FOI Document #6
IS
PIPE AND TUBING EXTRUSION 7
Control boxes should include safety devices to prevent
voltages greater than 42V AC for a 40V system being
present at the control box output. The safety device should
operate in less than 0.5 sec.
2. Peeling Tools
Rotational peeling tools must be capable of removing
a continuous and uniform chip thickness from the outer
oxidised surface, over the required insertion depth, when
preparing the fusion zone.
The benefits of alignment clamps are that they:
• Allow for re-rounding of pipes, particularly coiled pipes
that are oval
• Provide correct assembly and alignment of the pipe
with the fitting
• Enable the joint to be stabilised during the welding
heating and cooling cycle
• Are stress free joints
• Have uniform melt pressure within the joint
Hand scrapers are difficult to use, and effective
preparation is time consuming, physically demanding
and in most cases does not produce uniform scraping.
Therefore rotational scrapers or peeling tools are preferred
when welding occurs at pipe ends (see Figure 34).
Figure 35a: Re-rounding and Alignment Clamp
Assembly used for Wide Bore Pipe
Figure 34: Rotational Peeling Tool Used to Prepare
Pipe Ends
3. Re-rounding and Alignment Clamps
Re-rounding and alignment clamps or other approved
methods have to be used for restraining, aligning and
re-rounding pipes during the fusion cycle (see Figure 35a
and b).
Figure 35h: In-field Laying of Multi-Jointed Pipe
Qenos Technical Guides
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FOI Document #6
7 PIPE AND TUBING EXTRUSION
4. Pipe Cutters
Electrofusion Jointing Method
Pipe cutters are mounted instruments that are used
for the accurate cutting of pipes to ensure uniform and
perpendicular pipe end. Such cutting devices should
include the saw and saw guide (see Figures 36a and b).
Preparation of Pipe Ends
i. Ensure hands and tools are free from surface
contaminants, such as barrier hand cream, sun screen,
detergent and surfactant used in horizontal directional
drilling.
ii. Check equipment is complete, clean, undamaged, in
working order and protected by shelter.
iii. Ensure there is sufficient space to permit access to the
jointing area. In a trench, a minimum clearance of 150 mm
is required all round. Larger clearances may be needed
for large nominal pipe sizes, depending on the tool used.
iv. Check that the pipe ends to be jointed are cut square to
the axis and any burrs and swarf are removed.
Guillotine Pipe Cutter
Figure 36a: Examples of a Guillotine
v. Clean the fitting bore, followed by the pipe surface with a
new approved alcohol wipe to remove traces of dirt, mud
and other contamination. When using slip couplings
clean the entire area where the fitting will pass over the
pipe. The area of the pipe to be fusion jointed may be
washed with clean water if necessary and dried with lint
free material prior to peeling. Ensure the fusion area is
completely dry before proceeding (see Figure 37). Do not
use detergent or surfactants to clean pipe surfaces.
NOTE: Refer to fitting supplier for recommended alcohol
wipes. Personal cleaning wipes may contain lanolin and
detergent and are not to be used in electro fusion.
vi. Check ovality as described above and use re-rounding
tools as appropriate.
With the fittings still in the bag, place alongside the pipe
end and put a witness mark on the pipe at half the
fitting length plus about 40 mm to enable visual
checking of the scraped area after jointing is complete.
NOTE: Do not remove the fitting from its packaging at
this stage.
vii. Check that the pipe clamps are of the correct size for
the pipes to be jointed. Only use the correct size pipe
clamps.
Figure 36b: Motorised Hand Circular Saw Cutter
5. Weather Shelter
Suitable shelter should be used to provide shade and
protection for the pipe, fittings and equipment against
adverse weather conditions and contamination of the
jointing surfaces by dust and/or moisture, which can
result in unsatisfactory joints. Fittings should only be
removed from their original packaging immediately
before using for jointing.
28
viii.Check the peeling tools are clean of dirt or other
contaminants prior to use.
x. Using an appropriate peeling tool, remove the entire
surface of the pipe to the depth of the witness mark.
Metal files, rasps, emery paper, etc. are not suitable
end preparation tools and should not be used.
xi. Mechanical peeling tools are strongly preferred, as
they achieve a consistent pipe surface preparation.
Hand scraping, particularly for larger diameter pipes,
is time consuming and onerous to adequately prepare
a complete pipe end.
Qenos Technical Guides
FOI Document #6
PIPE AND TUBING EXTRUSION 7
xii.lt is important in Australia that pipe and fittings are
stored in the shade. If left in the sun, pipe and fittings
become very hot which may affect weld conditions,
particularly with thin pipe. When jointing in high ambient
temperature, it is important that the pipe jointing area is
shaded by an appropriate shelter. Some fittings do not
require adjustment to the heat cycle time for ambient
temperatures in the range -10°C to +45°C, whereas
others require heat cycle time variation to compensate
for ambient temperature within this range.
ENSURE THE PREPARED SURFACES ARE COMPLETELY
DRY BEFORE PROCEEDING
DO NOT TOUCH THE PREPARED PIPE SURFACE
Jointing Procedure
i. Wipe the prepared pipe surface only with a
recommended alcohol wipe to remove any dust residue
and other contaminants. For larger diameter pipes use a
multiple number of alcohol wipes.
NOTE: Cleaning of the prepared surface is a critical step
and one that has the potential to introduce contaminates
if not done correctly - remember this is the surface that
is about to be welded and the presence of contaminates
can readily result in a poorly welded joint. To avoid
contamination, ONLY wipe the peeled fusion zone area.
Do not under any circumstances use methylated spirits,
acetone, methyl ethyl ketone (MEK) or other solvents to
clean the fusion area. Rags are not recommended for
use with any alcohol solvent to clean the fusion area
given the possibility of dirt, detergent or fabric
conditioner being transferred into the fusion zone.
Other important factors relating to this procedure:
• Ensure wipes are saturated with alcohol i.e. have not
dried out.
Clean
• To avoid contamination ONLY wipe the peeled fusion
zone area.
• Only use the wipe once.
• Do not touch the prepared pipe surface - sweat,
sunscreen, barrier cream, dirt and skin oils are all
potential sources of contamination. Disposable latex
or nitrile gloves are recommended when handing the
wipes for preparation of the surface.
• Ensure alcohol left by the wipe on the cleaned surface
has evaporated and the prepared surfaces are
completely dry before assembling the joint.
• Refer to the electrofusion fitting supplier for the correct
selection of alcohol wipes.
ii. Remove the fitting from its packaging and check that the
bore of the fitting is clean. The bore of the fitting may be
wiped with an approved isopropyl wipe if necessary.
NOTE: Ensure the cleaned bore is completely dry before
proceeding.
Wipe
iii. It is good practice to install the fitting to both pipe ends
at the same time. However if this is not possible, open
only one end of the fitting package and install the fitting
to the pipe end. The package can then be fixed in place
to enclose the exposed end of the fitting to keep the
fitting bore free from contamination.
Figure 37: Illustration of Pipe End Preparation Prior
to Welding
Qenos Technical Guides
29
FOI Document #6
7 PIPE AND TUBING EXTRUSION
iv.
v.
Inscribe an accurate witness mark or insertion depth
onto the pipe and then insert the pipe ends into the
fitting so that they are in contact with the centre stop
and witness mark. It is critical that the pipe be fully
inserted, particularly for larger pipes or when there is
no centre stop. Ensure an aligned pipe arrangement in
order to avoid any stress during the jointing process,
especially when using coiled pipes.
The pipe end(s) and the fitting must be correctly
aligned and free of any bending stress. Use pipe
clamps, or other suitable means, to secure the pipe(s)
so they cannot move and ensure that the fitting is
satisfactorily supported to prevent it sagging during
the fusion procedure (see Figure 38).
NOTE: Automatic control boxes are available which
obviate the need to enter the fusion time.
x. If the control box is equipped with a barcode reader or
barcode scanner, scan the fusion data barcode into the
machine to ensure a fully automated and controlled
data entry. Barcode reading control boxes automatically
adjust for variable temperature conditions. For manual
input of the heat fusion time into the control box,
refer to the manufacturer's parameters, supplied with
the fitting.
Figure 39: Attachment of Control Box Leads to
Pipe Fitting
xi. Press the start button on the control box and check
that the heating cycle is proceeding as indicated by
the display.
Figure 38: Illustration of Pipe Clamps and Fitting
Attached to Pipe Ends Prior to Welding
vi.
Check that there is sufficient fuel for the generator to
complete the joint. Start the generator and check that
it is functioning correctly.
NOTE: Ensure the generator is switched on and
running satisfactorily before connecting the
electro fusion control box to the power source.
xii. On completion of the heating cycle, both melt indicators
within the processed part of the fitting should have
risen. If there is no apparent movement of either
indicator the joint could be unsatisfactory (see Figure
40) - refer to discussion on electrofusion indicator
pins below.
p.
'91
vii. Switch on the control box. Check that the reset button,
if fitted, is in the correct mode.
viii. Connect the control box output leads to the fitting
terminals and check that they have been fully inserted
(see Figure 39).
ix.
30
The jointing time is generally indicated either on the
fitting or on a data carrier supplied with the fitting.
Check that the correct time is shown on the control
box display. If required for the control box, enter the
fusion jointing time into the control box timer.
Figure 40: Diagram illustrating Locating of Melt
indicators
Qenos Technical Guides
FOI Document #6
PIPE AND TUBING EXTRUSION 7
xiii. If the fusion cycle terminates before completion of
the countdown, check for faults as indicated by the
control box warning lights or display. Check for a
possible cause of the break, e.g. inadequate fuel in
the generator, or power supply failure, etc.
NOTE: Do not attempt a second fusion cycle until
the entire fitting has cooled to less than 45°C. Some
manufacturers recommend replacement of the fitting
rather than a second fusion cycle. Refer to the fitting
manufacturer for details.
xiv. The completed joint should be left in the clamps for
cooling. The time needed will be specified on the
fitting, or by its data carrier, or in the display of the
automatic control box.
xiv. When the joint has cooled, remove it from the clamps
and inspect.
Electrofusion Indicator Pins
The fusion indicator protrusion following the completion
of the fusion process indicates that fusion pressure has
developed but does not guarantee the quality of the joint.
The height of the extended pin is dependent upon the
fitting in use, component tolerances and the pipe material.
The pins are used as a pointer to whether a more detailed
inspection of the joint is required so in the event that the
pin does not rise, the supervisor or operator must investigate
the following to determine if the joint is satisfactory.
• Dimensional check and compliance of the pipe spigot
OD and ovality.
• The fitting socket internal diameter by measurement
or batch traceability.
• In the case where the pipe and socket are concentric,
the maximum gap between the two should not exceed
1% of the nominal diameter. If the socket and spigot are
eccentric the gap should not exceed 2%.
• That there is no disruption to the input power supply from
the fusion box with no control box error messages.
• That the heat fusion parameters are correct.
• The pipe to fitting alignment is correct with no visible
plastic extruded out from the fitting.
Qenos Technical Guides
Maintenance, Servicing and Calibration
All equipment should be well maintained and kept in
a clean condition at all times.
The equipment should be serviced and calibrated regularly.
The frequency at which this is carried out will be different
for individual items of equipment and will also depend on
usage, but should be at least once every 12 months.
Guidance should be sought from the equipment
manufacturer and a scheme of calibration and servicing
should be implemented. Particular attention should be
given to the control box, the generator and the scraping
(or peeling) tools. The sharpness of the cutter head of the
tools should be checked at least on a monthly base.
Records
1. Job Supervision
Electronic or written records of appropriate fusion
procedure for each joint should be kept as required.
2. Equipment Servicing and Calibration
Electronic or written records of appropriate servicing and
calibration should be kept. The minimum information to be
recorded is given in Appendix 1.
3. Training
Instructions should be provided by Registered Training
Organisations (RTO's) that are accredited by State/Territory
Training Authorities under the Australian National Training
Authority (ANTA) guidelines and complying with PMB 01Competency Standards prepared by Manufacturing
Learning Australia, Qualification Framework for the plastics,
rubber and cable making industry.
The RTO's providing training in all forms of welding plastics
pipeline systems must have staff qualified in presenting
courses that meet competency standards covered by
sections PMBWELD301A through to PMBWELD311A in
PMB 01.
The RTO's normally issue an accreditation certificate to
successful candidates completing the training course and
maintain a register of accredited welders.
31
FOI Document #6
7 PIPE AND TUBING EXTRUSION
Electrofusion Saddle Jointing
Electrofusion saddle jointing incorporates an electrical
resistance element in the base of the saddle which, when
connected to an appropriate power supply, melts and fuses
the materials of the pipe and fitting together (see Figure 41).
Electrofusion tapping saddles are available to fit all
commonly used main sizes from DN40 to DN560 with
service connection outlet sizes from DN20 to DN63 and
branch saddle spigot off-takes from DN32 to DN125.
NOTE: Some saddle type fittings are limited to SDR11.
Refer to the fitting manufacturer for further details.
Tapping tee saddles are usually supplied complete with
the manufacturer's recommended installation procedure.
Generally recommended installation parameters are
similar to the procedure described here, which refers
to fittings supplied with an underpart with bolts for
assembling the two parts on the pipe.
The nominal pipe diameter should be within the tolerances
specified in AS/NZS 4130. Pipe ovality in excess of 1.5%
of the nominal pipe diameter (DN) will require re-rounding
tools to allow satisfactory contact between tapping saddle
and pipe. Some full circle tapping saddles may effectively
re-round pipe when correctly fitted but a constant and
reliable joint quality can always be achieved by using
re-rounding tools. If in doubt, refer to the fitting supplier.
Equipment
Figure 41: Polymer Fitting that can be Welded onto a
Pipe by Electrofusion Saddle Joining
The effectiveness of this technique depends on attention
to preparation of the jointing surfaces, in particular the
removal of the oxidised surface of the pipe over an area
equivalent to the saddle base, and the cleaning of the
jointing surfaces and freedom from contamination.
Although PE is comparatively inert, the outer surface
of the pipe will become oxidised when exposed to the
atmosphere. This oxidised outer layer will interfere with
the bond between the pipe and fitting and must therefore
be removed before joint assembly.
i. The control box input supply should be from a nominal
240V generator suitable to drive inductive loads and
phase cut systems, commonly of about 5kVA capacity.
Some fitting suppliers may consider smaller capacity
generators acceptable for small diameter fittings. The
nominal output of the generator should be 240V +15%,
-15% between no load and full load. It should be noted
that electrofusion control boxes may generate
considerable heat. Refer to the supplier of the controller
for details. Control boxes should include safety devices
to prevent voltages greater than 42V AC for a 40V
system being present at the control box output. The
safety device should operate in less than 0.5 sec.
ii. Pipe surface preparation tool (scraper or peeler) has to
be capable of removing the oxidised surface of the pipe
over the full area of the saddle base. The tool should
remove a surface layer of between 0.2 mm and
0.4 mm. Hand scrapers can be difficult to use in trench
conditions, and effective preparation by hand may be
time consuming and physically demanding. Therefore
rotational scrapers or peeling tools are preferred.
iii. Re-rounding clamps or other approved methods of
re-rounding pipes should be used, particularly if pipe
out of roundness exceeds 1.5%.
32
Qenos Technical Guides
FOI Document #6
PIPE AND TUBING EXTRUSION 7
iv. A pipe clamp of suitable dimensions for making the
service or branch connection is needed.
v. Pipe cutters should include a saw and saw guide.
vi. Suitable shelter should be used to provide adequate
protection for pipe, fittings and equipment against
adverse weather conditions and contamination of the
jointing surfaces by dust and/or moisture, which can
result in unsatisfactory joints. Fittings should only be
removed from their original packaging immediately
before using for jointing.
Preparation
i. Ensure hands and tools are free from surface
contaminants, such as barrier hand cream, sun screen,
detergent and surfactant used in horizontal directional
drilling.
ii. Expose the pipe onto which the tapping tee or saddle is
to be assembled, ensuring there is clear space around
the pipe. In a trench a minimum clearance of 150 mm is
required all round. Larger clearances may be needed for
larger nominal sizes, depending on the tool used.
iii. Wipe the joint area, where the saddle is to be fitted, with
alcohol wipes to remove traces of dirt, mud and other
contamination. The joint area may be washed with clean
water if necessary and dried with lint free material prior
to scraping. Ensure the joint surface is completely dry
before proceeding. Do not use detergent or surfactants
to clean pipe surfaces.
NOTE: Refer to fitting supplier for recommended alcohol
wipes. Personal cleaning wipes may contain lanolin and
detergent and are not suitable for use in electro fusion.
iv. Without removing the fitting from its packaging, place
it over the required position on the pipe. Mark the
pipe surface outlining the saddle base area plus about
20 mm with a suitable marker pen to allow for visual
checking of the scraped area after jointing is complete.
v. Check ovality as described above and use re-rounding
tools as appropriate.
vi. Using an appropriate preparation tool remove the entire
surface of the pipe over the full area marked. If hand
scrapping, ensure long even scrapes starting outside
the marked area to ensure craters do not occur in the
fusion zone, which can produce an excessive gap
leading to a brittle weld. Remove the swarf. Metal files,
rasps, emery paper, etc. are not suitable scraping tools
and should not be used.
Qenos Technical Guides
vii.It is important in Australia that pipe and fittings are
stored in the shade. If left in the sun the pipe and
fittings become very hot which may affect weld
conditions, particularly with thin pipe. When jointing in
high ambient temperature, it is important that the pipe
jointing area is shaded by an appropriate shelter. Some
fittings do not require adjustment to the heat cycle
time for ambient temperatures in the range -10°C to
+45°C, whereas others require heat cycle time
variations to compensate for ambient temperature
variation within this range.
Jointing Procedure
I. Wipe the prepared surface only with the manufacturer's
approved alcohol wipe to remove any dust residue and
other contaminants. For larger diameter pipes a multiple
number of alcohol wipes shall be used.
NOTE: Cleaning of the prepared surface is a critical
step and one that has the potential to introduce
contaminates if not done correctly - remember this is
the surface that is about to be welded and the presence
of contaminates can readily result in a poorly welded
joint (see Figure 42).
Do not under any circumstances use methylated spirits,
acetone, methyl ethyl ketone (MEK) or other solvents.
Do not use rags or other cloth soaked in these
materials to wipe the prepared fusion surface as they
have the potential to contaminate the surface with dirt,
grease and fabric conditioner. These are not suitable
options for wiping the prepared surface.
Other important factors relating to this procedure:
• Ensure wipes are saturated with alcohol i.e. have not
dried out.
• When using the wipe work from the prepared (peeled)
surface towards the unprepared area and discard the
wipe after it has come in contact with any unprepared
areas. Wiping from unprepared areas towards the
prepared surface can contaminate the fusion surface
and similarly using a wipe which has been used on an
unprepared can also introduce contaminants.
• Only use the wipe once.
• Do not wipe over the witness mark.
• Do not touch the prepared pipe surface - sweat,
sunscreen, barrier cream, soap, detergent, dirt and skin
oils are all potential sources of contamination.
Disposable latex or nitrile gloves are recommended when
handing the wipes for preparation of the surface.
33
FOI Document #6
tI
7 PIPE AND TUBING EXTRUSION
• Ensure alcohol left by the wipe on the cleaned
surface has evaporated and the prepared surfaces
are completely dry before assembling the joint.
• Refer to the electrofusion fitting supplier for the
correct selection of alcohol wipes.
ENSURE THE PREPARED SURFACES ARE COMPLETELY
DRY BEFORE PROCEEDING
DO NOT TOUCH THE PREPARED PIPE SURFACE
ii. Position the fitting base onto the prepared pipe surface.
Bring the lower saddle into position. Then gradually and
equally tighten the bolts and nuts until the upper saddle
makes firm contact with the prepared surface of the
pipe (see Figure 43). Carefully inspect the fitting to
ensure a firm contact with the pipe is achieved over the
entire upper saddle contact area. Install re-rounding
tools if pipe out of roundness exceeds 1.5% or if a firm
contact is not achieved over the entire upper saddle
contact area.
(
Figure 42: Illustration of Pipe Preparation Required Prior
to Welding of Pipe Fitting
Remove the fitting from its packaging and check that the
jointing surface of the saddle fitting is clean. The bore of
the fitting may be wiped with a recommended alcohol wipe
if necessary.
NOTE: Ensure that the bore is completely dry
before proceeding.
Figure 43: Installation of Saddle Fitting onto Pipe Prior
to Welding
iii. Check that there is sufficient fuel for the generator to
complete the joint. Start the generator and check that it
is functioning correctly.
NOTE: Ensure the generator is switched on and running
satisfactorily before connecting the electro fusion
control box to the power source.
iv. Switch on the control box. Check that the reset button,
if fitted, is in the correct mode.
v. Connect the control box output leads to the fitting
terminals and check that they have been fully inserted
(see Figure 44).
34
Qenos Technical Guides
FOI Document #6
PIPE AND TUBING EXTRUSION 7
Figure 44: Attachment of Control Box Leads to
Pipe Fitting
vi. The jointing time is indicated either on the fitting label
or on a data carrier supplied with the fitting. Check that
the correct time is shown on the control box display. If
required enter the fusion jointing time into the control
box timer.
NOTE: Automatic control boxes are available which
obviate the need to enter fusion time.
vii. If the control box is equipped with a barcode reader or
barcode scanner, scan the fusion data barcode into the
machine to ensure a fully automated and controlled
data entry. Barcode reading control boxes automatically
adjust for variable temperature conditions. For manual
input of the heat fusion time into the control box, refer
to the manufacturer's or supplier's parameters, which
should be supplied with the fitting.
C)
viii. Press the start button on the control box and check
that the heating cycle is proceeding as indicated by the
display.
ix. On completion of the heating cycle, the melt indicator
on the fitting should have risen (see Figure 45). If
there is no apparent movement the joint could be
unsatisfactory - refer to the manufacturer's
instructions for further information.
Qenos Technical Guides
Figure 45: Diagram illustrating Locating of Melt
indicators on Fitting
Refer to the fitting supplier or manufacturer for details on
branch outlets and specific installation instructions.
x. If the fusion cycle terminates before completion of the
countdown, check for faults as indicated by the control
box warning lights or display. Check for a possible
cause of the break, e.g. inadequate fuel in the
generator, or power supply failure, etc.
NOTE: DO NOT attempt a second fusion cycle until the
entire saddle fitting has cooled to less than 45°C. Some
manufacturers recommend replacement of the fitting
rather than a second fusion cycle. Refer to
manufacturer for details.
xi. The completed joint should be left in the clamps for
cooling. The time needed will be specified on the fitting
label, or by its data carrier, or in the display of the
automatic control box.
xii. The connection of the service pipe to the spigot
outlet should be carried out in accordance with the
procedure of the appropriate section of these
guidelines (see Figure 46).
35
FOI Document #6
7 PIPE AND TUBING EXTRUSION
Figure 46: Illustration of Tapping Process used to
Connect Spigot Outlet to Main Service Pipe
xiii. DO NOT attempt to tap the main with the integral
cutter before the completion of the required cooling
cycle as specified by the supplier.
Additional cooling time is recommended before tapping
if the pipeline is to be field pressure tested as soon as
practical:
Figure 47: Installation of Detachable Rotary Peeler to
Service Pipe
iii. Clean pipe in the fusion zone with an approved alcohol
wipe (see Figure 48).
• DN40 saddle minimum 10 minutes for field test
pressure 6 bar and minimum 30 minutes for field
test pressure > 6 bar 24 bar
• DN63 - DN560 saddle minimum 20 minutes for field
test pressure 6 bar and minimum 60 minutes for
field test pressure > 6 bar 24 bar
Top load Electrofusion Branch Saddle Jointing
Top load electrofusion branch saddles are typically used
for large diameter branch connections 90 mm.
Applications include: new installations, renovation, repair
and under pressure live branch connections on existing
PE mains for sizes to DN630 mm.
Typical installation instructions are detailed below:
i.
Ensure hands and tools are free from surface
contaminants, such as barrier hand cream, sun screen,
detergent and surfactant used in horizontal directional
drilling.
ii. Clean pipe in the fusion area with an approved alcohol
wipe as detailed above in the Jointing Procedure, then
remove the oxidised layer with a rotary peeler (see
Figure 47).
36
Figure 48: Illustration of Prescribed Cleaning of Pipe
Fusion Zone
iv. Mount the fitting to the pipe using a top-load tool and
tightening clamp device to ensure a positive contact is
made between the pipe and saddle. The joint gap should
not exceed 0.5 mm (see Figure 49).
Qenos Technical Guides
FOI Document #6
PIPE AND TUBING EXTRUSION 7
Records
1. Job Supervision
Electronic or written records of appropriate fusion
procedure for each joint should be kept as required.
2. Equipment Servicing and Calibration
Electronic or written records of appropriate servicing and
calibration should be kept. The minimum information to be
recorded is given in Appendix 1.
3. Training
Figure 49: Illustration of Top-load Tool Attached to Both
the Saddle and Pipe
v. Connect the terminals and apply the fusion voltage
following the method outlined above in Jointing
Procedure.
vi. The completed joint should be left in the clamps for
cooling. The time needed will be specified on the fitting
label, or by its data carrier, or in the display of the
automatic control box.
Maintenance, servicing and calibration
All equipment should be well maintained and kept in a
clean condition at all times.
The equipment should be serviced and calibrated regularly.
The frequency at which this is carried out will be different
for individual items of equipment and will also depend on
usage, but should be at least once every 12 months.
Guidance should be sought from the equipment
manufacturer and a scheme of calibration and servicing
should be implemented. Particular attention should be
given to the control box, the generator and the scraping
(or peeling) tools. The sharpness of the cutter head of
tools should be checked at least on a monthly base.
Qenos Technical Guides
Instructions should be provided by Registered Training
Organisations (RTO's) that are accredited by State/Territory
Training Authorities under the Australian National Training
Authority (ANTA) guidelines and complying with PMB 01 Competency Standards prepared by Manufacturing
Learning Australia, Qualification Framework for the plastics,
rubber and cable making industry.
The RTO's providing training in all forms of welding
plastics pipeline systems must have staff qualified in
presenting courses that meet competency standards
covered by sections PMBWELD301A through to
PMBWELD311A in PMB 01.
The RTO's normally issue an accreditation certificate to
successful candidates completing the training course and
maintain a register of accredited welders.
Quality Assurance
To achieve consistently good quality fusion joints as
outlined by these guidelines, manufacturers and installers
should operate a quality system in accordance with the
principles of AS/NZS ISO 9001.
Assessment of the achievement would take the form of
an audit against the points below. Independent testing of
fusion joints may also be required.
37
FOI Document #6
7 PIPE AND TUBING EXTRUSION
Management Responsibility
3. Inspection and Testing
1. Customer Focus
a. Inspection of goods received and used on site
The installer should ensure that incoming pipe, fittings
and fusion jointing equipment are not used until they
have been inspected and confirmed as conforming to
specified requirements including appearance and
marking. Any non-conforming items should be identified,
recorded and segregated.
The organisation responsible for the jointing operation should
ensure that customer requirements are determined and are
met with the aim of enhancing customer satisfaction.
2. Planning
The organisation responsible for the jointing operation
should ensure that all aspects of the jointing operation are
given adequate consideration prior to the commencement
of work.
3. Responsibility, Authority and Communication
On each site where pipes and fittings are to be jointed in
accordance with these guidelines, a person should be
nominated to supervise work affecting the jointing quality.
The person should:
• Have the responsibility and authority to ensure effective
jointing operations
• Ensure that processes needed for jointing operations are
established, implemented and maintained
• Be able to communicate the requirements for effective
jointing operations
b. Final inspection and testing
At the commencement of each contract, the frequency
and type of inspection by the installer should be agreed
with the client and documented.
c. Inspection and test records
The installer should establish and maintain electronic
and/or written records of appropriate fusion jointing
procedures, servicing and calibration details in
accordance with these guidelines.
4. Corrective Action
The installer should establish and maintain procedures
to show evidence of:
• Review of non-conformities (including customer
complaints) as a result of poor quality joints
Control of Documents
• Determining the causes of poor quality joints
Document control should ensure that:
• Evaluating the need for action to ensure poor quality
joints do not recur
• Documents are approved for adequacy prior to use,
• The relevant versions of applicable documents are
available at points of use,
• Documents remain legible and readily identifiable,
• The unintended use of obsolete documents is prevented,
and to apply suitable identification to them if they are
retained for any purpose.
1. Purchasing
The installer should ensure that purchased items including
pipe, fittings and fusion jointing equipment conform to
specified requirements.
• Determining and implementing action needed
• Recording the results of action taken, and
• Reviewing corrective action taken
5. Preservation of Product
The installer should establish and maintain appropriate
procedures for handling and storage of pipe, fittings and
fusion jointing equipment on site.
NOTE: Damaged packaging can permit ingress of dirt and
moisture, which can adversely affect joint integrity.
6. Control of Records
2. Fusion Jointing Control
The installer should ensure that fusion jointing procedures
as well as servicing and maintenance of fusion jointing
equipment are carried out in accordance with the specified
guidelines.
38
The installer should establish and maintain procedures for
collection, indexing, filing and storage of quality records for
a minimum period of 6 years from the date of installation.
Qenos Technical Guides
FOI Document #6
(2.
PIPE AND TUBING EXTRUSION 7
7. Competence, Awareness and Training
The installer should:
• Determine the necessary competence for personnel
performing fusion jointing
• Provide training or take other actions to satisfy these
guidelines
• Evaluate the effectiveness of the actions taken
• Ensure that personnel are aware of the relevance and
importance of their activities and how they contribute to
the achievement of effective fusion jointing, and
• Maintain appropriate records of education, training, skills
and experience
Qenos Technical Guides
39
FOI Document #6
7 PIPE AND TUBING EXTRUSION
APPENDIX 1- RECORD SHEETS
Record sheets should be maintained for all equipment
required for all fusion jointing operations. The sheet should
be headed:
'SERVICING AND CALIBRATION RECORD SHEET'
Followed by:
`ELECTROFUSION SOCKET EQUIPMENT OR
ELECTROFUSION SADDLE EQUIPMENT'
Then the appropriate sub-title from the following list
(additional record sheets may be kept if required):
0
• Electrofusion socket jointing:
• Generators
• Electrofusion control box
• Electrical safety test
• Electrofusion saddle jointing:
The information recorded on the sheet should include,
but not be restricted to:
• The date of servicing or maintenance
• The name, address and telephone number of the
undertaking or contractor operating the equipment
• The name, address and telephone number of the
company conducting the service or maintenance
• The member (or members) of staff responsible for
servicing or maintenance
• The serial number of the equipment
• The details of service and/or maintenance carried out.
This should include relevant details of test equipment,
procedures and/or manuals used, and relevant ambient
conditions.
• The signature(s) of the member (or members) of staff
responsible for the servicing or maintenance operations
conducted
• Generators
• Electrofusion control box
• Electrical safety test
40
Qenos Technical Guides
FOI Document #6
PIPE AND TUBING EXTRUSION 7
APPENDIX 2 - PIPE EXTRUSION TROUBLESHOOTING GUIDE
Problem/ Issue
Cause(s)
Potential Solution(s)/ Action(s)
Die (extrudate)
lines.
Damage to the exit edges of the tip or die.
Refinish tip or die exit edges to sharp and uniform
about the diameters.
Die drool or build-up on the tip or die faces.
Adjust temperature of the die exit accordingly
Too fast extruder throughput relative to OEM
Extruder specifications
Check OEM guaranteed extruder throughput and
run extruder within specifications
Improper extruder temperature settings
Adjust temperature setting according to OEM
recommendations
Extruder surging
Poor resin- extruder design match versus extruder Discuss with resin supplier and implement actions
OEM specifications for throughput
to ensure extruder runs within OEM specifications
Extruder not set as per OEM design specifications Check with OEM and ensure compliance with design
specifications
Gels and other
contaminations
in pipe
Resin contains foreign particles/ contaminated
with gels etc
Degraded resin coming off the die during extrusion
Follow proper shut-down procedures for extruder
to avoid long exposure of resin to excessive
temperatures
Localised thick
spots in pipe wall
Improper die setting
Adjust the die setting
Hot and cold spots in die profile temp
Check for uniformity in die heating
Uneven pipe drag downstream of the extruder
Check for spots in cooling baths which could cause
pipe drag
Haul-off slippage
Check and adjust haul-off
Uneven melt delivery from die -extruder surging
Check remedies for extruder surging
Vacuum calibrator and die not levelled well
Adjust the position of the vacuum bath relative
to the die
Sizing device (calibrator) in adequate or out
of shape
Check the calibrator for concentricity.
Pipe is too warm when it reaches the haul off unit
Ensure sufficient downstream cooling length before
pipe gets to the haul off unit
Pipe out of round
Check with resin supplier for presence of gels etc.
Check regrind for contaminants
Ensure it is 3-5% larger than the final pipe diameter
Decrease throughput
Pipe tear
Wrong vacuum setting in vacuum tanks
Ensure proper vacuum setting in vacuum tanks
Haul-off too fast
Check and adjust the speed of haul off
Pipe too hot at the entrance to calibrator
Check for water flows on calibrator and adjust to
avoid hot spots
Ensure adequate calibrator size
Pipe sag
Pipe dragging in cooling tanks
Check and eliminate drag spots
Melt temperature too high
Adjust extruder temperature setting and throughput
to lower melt temperature
Die gap not adjusted to accommodate sag
Adjust die gap - wider at the top and narrower at the
bottom of the die
Resin's inherent resistance to sag is not adequate Use low-sag resin
for the pipe wall thickness
No enough cooling capability in line
Qenos Technical Guides
Ensure adequate water temperature in cooling baths
and enough cooling length
41
FOI Document #6
7 PIPE AND TUBING EXTRUSION
Problem/ Issue
Cause(s)
Potential Solution(s)/ Action(s)
Rough surface
inside or outside
Moisture in resin
Ensure minimum of 1.5 hrs drying of resin at
70-90°C
Not adequate water flows setting to the calibrator
Adjust water flows to calibrator
Melt temperature too low
Increase die/ and or extruder temperatures
Too high melt temperature
Adjust extruder/ and or die temperatures accordingly
Excessive extruder screw speed
Lower extruder throughput
Die too small for required throughput
Ensure adequate die size
Die pin too hot
Check operation of pin cooling otherwise decrease
throughput
Extruder surging
Check remedies for extruder surging
The saw blade is flexing
Get thicker/ larger blades
The saw blade is lose
Check and fix
Saw arm is entering pipe too quickly and with
insufficient revolutions
Adjust as required
Thermal
degradation of
pipe-failed OIT
Uneven pipe cut
The saw arm is lose or bushes worn and is 'floating' Check and fix
Uneven wall
thickness
Voids in pipe
There is wear/slack in slip rings of the saw
planetary components
Check and fix
Uneven speed of haul-off or cutting carriage
Check uniformity of the speed of haul-off and
cutting carriage
Saw is not capable of cutting the pipe
Check with OEM for saw specifications
Uneven melt delivery from the die -extruder surging Check remedies for extruder surging
Uneven take-off speed
Check haul-off unit
Improper alignment of die and haul-off units
Check for alignment
Die and pin not centred evenly
Even die gap
Excessive sag of a polymer
Check remedies for pipe sag
Moisture in resin
Ensure minimum of 1.5 hrs drying of resin at
70-90°C
Trapped air
Adjust extruder temperature setting and back
pressure accordingly
Disclaimer
The proposed solutions in this guide are based on conditions that are typically encountered in the manufacture of products from polyethylene.
Other variables or constraints may impact the ability of the user to apply these solutions. Qenos also refers the user to the disclaimer at the beginning
of this document.
42
Qenos Technical Guides
FOI Document #6
PIPE AND TUBING EXTRUSION 7
BIBLIOGRAPHY/FURTHER READING
1. Janson, L. E.; Plastic Pipes for Water Supply and Sewage Disposal (4th Ed.), Borealis, 2003.
2. Bromstrup, H.; PE100 Pipe Systems (2" Ed.), Vulkan-Verlag GmBH, 2004.
3. Hensen, F.; Plastic extrusion Technology, Hanser Verlag, 1997.
4. Michaeli, W.; Extrusion Dies, Hanser Verlag, 2003.
5. Technical Manual - Materials for Pipe Extrusion, Hostalen, Lupolen, -Processing and Applications, Basell Polyolefins.
6. Reliable Pipelines with Hostalen CRP 100, Properties, Practical Experience and Standards, Hoechst.
7. Batten feld Extrusionstechnik - SMS Group, Pipe Extrusion Plant.
8. AS/NZS 4131:2010, Polyethylene (PE) compounds for pressure pipes and fittings.
9. AS/NZS 4130:2009, Polyethylene (PE) pipes for pressure applications.
C
10. ISO 9080:2003, Plastic piping and ducting systems - Determination of the long-term hydrostatic strength of
thermoplastics materials in form by extrapolation.
11. ISO 13479:2009, Polyole fin pipes for the conveyance of fluids - Determination of resistance to crack propagation Test method for slow crack growth on notched pipes (notch test).
12. ISO 13477:2008, Thermoplastic pipes for the conveyance of fluids - Determination of resistance to rapid crack
propagation (RCP) - Small-scale steady-state test (S4 test).
13. ISO 4437:2007, Buried polyethylene (PE) pipes for the supply of gaseous fuels - Metric series - Specifications.
14. ISO 4427 - 1:2007, Plastics piping systems - Polyethylene (PE) pipes and fittings for water supply.
PMBWELD3016 Butt Weld PE Pipelines Resource Manual, Chisholm Institute, 2010
15. Industry Guidelines, Butt Fusion Jointing of PE Pipes and Fittings, PIPA, 2011.
16. Industry Guidelines, Butt Fusion Jointing of PE Pipes and Fittings for Pressure Applications, PIPA, 2011.
17. Industry Guidelines, Temperature Rerating of PE Pipes, PIPA, 2010.
Issued January 2014.
Qenos Technical Guides
43
FOI Document #6
ger105
Qenos Pty. Ltd.
ABN: 62 054 196 771
Cnr Kororoit Creek Road & Maidstone Street,
Altona Victoria 3018, Australia
T: 1800 063 573 F: 1800 638 981
cienos.corn
OvalAy
t50 9001
sft also,
A
FOI Document #7
UNCLASSIFIED
s47F
From:
Sent:
To:
Subject:
Attachments:
s47F
Categories:
objections
@qenos.com
Thursday, 4 September 2014 9:12 AM
TARCON
Objection Gazette no TC 14/33, TC 1425825
TO 1425825 objection Sep 14 signed.pdf; HD3690-CON item cost.xlsx; Polyethylene at
a Glance 6th Edition.pdf; Book 5 injection Moulding.pdf
Dear National Manager, Tariff Branch
Please find attached Qenos' objection to Gazette no TO 14/33, TO 1425825 and supporting material.
s47F
s47F
Qenos Pty Ltd
P: s47F
I M: s47F
ftgenos.com I W: www.aenos.com
E: ds47F
Qenos
1
UNCLASSIFIED
FOI Document #8
\14-1
polo If this form was completed by a business with fewer than 20 employees,
please provide an estimate of the time taken to complete this form.
••N
•
••••
TIME1
SAVER
Hours
Minutes
SUBMISSION OBJECTING TO THE MAKIMG OF A
TARIFF CONCESSION ORDER (TCO)
THIS FORM MUST BE COMPLETED BY A LOCAL MANUFACTURER WHO WISHES TO OBJECT TO THE GRANTING OF A TCO.
THE INFORMATION PROVIDED ON THIS PAGE WILL BE FORWARDED TO THE APPLICANT FOR THE TCO.
THE FORM SHOULD BE READ CAREFULLY BEFORE BEING COMPLETED.
DETAILS OF THE TCO APPLICATION TO WHICH THIS SUBMISSION REFERS
GAZETTE NO
DATE 27 August 2014
TC 14/33
Gazetted description of goods.
TC Reference Number
TC
1425625
RESINS, unpigmented polypropylene heterophasic copolymer,
proplyene based with comonomer ethylene, in pelletised form,
having ALL of the following: (refer TC 1425825)
Stated use: For the manufacture of this walled containers for food and
industrial packaging using high speed injection moulding
LOCAL MANUFACTURER DETAILS
Name
Qenos
Business Address
471-513 Kororoit
Creek Road, Altona VIC 3018
Postal Address (if the same as business address write "as above")
Private Mail Bag 3, Altona VIC 3018
Reference
Australian Business Number (A.B.N.)
62 054 196 771
Company Contact
s47F
Phone Number
s47F
Facsimile Number
s47F
E-mail Address
@qenos.com
s47F
DETAILS OF THE SUBSTITUTABLE GOODS PRODUCED IN AUSTRALIA
Describe the locally produced substitutable goods the subject of the objection.
"Substitutable goods" are defined in the Customs Act 1901 as "goods produced in Australia that are put, or are capable of being put, to a use that
corresponds with a use (including a design use) to which the goods the subject of the application or of the TCO can be put",
High density polyethylene (HDPE) injection moulding resin.
2
State the use(s) to which the substitutable goods are put or are capable of being put.
Housewares, thin walled containers and closures.
0444 (JUN 2001
FOI Document #8
3
Attach technical, illustrative descriptive material and/or a sample to enable a full and accurate identification and
understanding of the substitutable goods.
4
Are you aware of any other local manufacturers producing substitutable goods?
5
If yes to question 4, please provide details of any goods produced in Australia which are substitutable for the goods for
which a TCO is being sought, and the names and addresses of the manufacturers of those goods.
6
PRODUCTION OF GOODS IN AUSTRALIA
YES
NO
Goods other than unmanufactured raw products will be taken to have been produced in Australia if:
(a)
the goods are wholly or partly manufactured in Australia; and
(b)
not less than 1/4 of the factory or works costs V the goods is represented by the sum of:
(i) the value of Australian labour; and
(ii) the value of Australian materials; and
(iii) the factory overhead expenses incurred in Australia in respect of the goods.
Goods are to be taken to have been partly manufactured in Australia if at least one substantial process in the manufacture of the goods
was carried out in Australia.
Without limiting the meaning of the expression "substantial process in the manufacture of the goods", any of the following operations or
any combination of those operations DOES NOT constitute such a process:
operations to preserve goods during transportation or storage;
(a)
(b)
operations to improve the packing or labelling or marketable quality of goods;
(c)
operations to prepare goods for shipment;
(d)
simple assembly operations;
operations to mix goods where the resulting product does not have different properties from those of the goods that have been mixed.
(e)
ID NO
A
Are the goods wholly or partly manufactured in Australia?
E
•
Does the total value of Australian labour, Australian materials and factory overhead
expenses incurred in Australia represent at least 25% of the factory or works costs?
E YES DNO
YES
Specify each of the following costs per unit for the substitutable goods:
s47
s4
7
• Australian materials
s
G
4
• Australian factory overhead expenses
s
s47G
7
4
• Imported content
G
s
s47G
7
4
G
TOTAL
s47G
7
Specify the date or period to which the costs relate. 12 months ending
G 31 Aug 2014
• Australian labour
s47
G
s47G
Attach a copy of the working papers that were used to prepare the above costing information. Those working papers should be
supported by (at least two) extracts from the accounting records of the business.
•
Is at least one substantial process in the manufacture of the goods carried out in Australia?
E YES
El NO
If yes, please specify at least one major process involved:
Conversion of Ethane gas supplied from Bass Strait into ethylene using a steam cracking process and then
polymerised into polyethylene at Qenos's Altona Victoria polymer manufacturing facility.
FOI Document #8
7
PRODUCTION OFGOODSIN THE ORDINARYCOURSE OF BUSINESS
{Answer 7.1 or 7.2)
7.1
SUBSTITUTABLE GOODS OTHER THAN MADE-TO-ORDER CAPITAL EQUIPMENT
Substitutable ,goods (other than made-to-order capital equipment) are taken to be produced in Australia in the ordinary course of business lE
(a)
they have been produced in Australia in the 2 years before the application was lodged; or
(b)
they have been produced, and are held in stock, in Australia; or
(c)
they are produced in Australia on an intermittent basis and have been so produced in the 5 years before the application was
lodged;
and a producer in Australia is prepared to accept an order to supply such goods.
A
Have the goods been produced in Australia in the last 2 years?
EYES
0 NO
•
Have the goods been produced and are they held in stock in Australia?
DYES
ONO
•
If the goods are intermittently produced in Australia, have they been so produced
JZI YES 0 NO
in the last 5 years?
•
Are you prepared to accept an order for the goods?
7.2
SUBSTITUTABLE GOODS BEING MADE-TO-ORDER CAPITAL EQUIPMENT
IZI YES 0 NO
"Made-to-order capital equipment" means a particular item of capital equipment that is made in Australia on a one-off basis to meet
a specific order rather than being the subject of regular or intermittent production and that is not produced in quantities indicative of
a production run. Capital equipment means goods which, if imported, would be goods to which Chapters 84, 85, 86, 87, 89 or 90
of Schedule 3 to the Customs Tariff Act 1995 would apply.
Goods that are made-to-order capital equipment are taken to be produced in Australia in The ordinary course of business if:
(a)
a producer in Australia:
(1)
has made goods requiring the same labour skills, technology and design expertise as the substitutable goods in the 2 years
before the application; and
(ii)
could produce the goods with existing facilities; and
(b)
the producer in Australia is prepared to accept an order to supply the substitutable goods.
•
Have goods requiring the same labour skills, technology and design expertise as the
goods the subject of the application been made in Australia in the last 2 years?
D YES
12 NO
If yes, describe the goods made during this period:
•
Can the goods be produced with existing facilities?
DYES 0 NO
•
Are you prepared to accept an order for the goods?
•
8
What was the first date on which you were prepared to accept an order?
Are the goods still in production?
If the answer is no, when did production cease?
If production has ceased and goods are held in stock, please estimate the date by
which stock is expected to be sold, based on past sales information and attrition
rate of the local goods.
YES ONO
/1
1
•
YES
/1980
ONO
FOI Document #8
/3-9
9
Provide any additional information in support of your objection.
Cost analysis based on the bill of materials (provided) for Qenos grade HD3690 packaged in 20 tonne
bulk containers for local delivery. Please advise if further cost information is required.
This product has been in production for several decades - the answer to question 8 on the first date
on which Qenos was prepared to accept an order is indicative only.
A copy of Qenos' product guide "Polyethylene at a glance" and Qenos' technical guide on
injection moulding have been provided in response to question 3.
NOTES
(a) Section 269K and 269M ofthe Customs Act 1901 require thata submission opposing the making of a TCO be in writing,
be in an "approved form", contain such information as the form requires, and be signed in the manner indicated in the
form. This is the approved form for the purposes of those sections.
(b) A submission will be date stamped on the day it is first received in Canberra by an officer of Customs. The submission
is taken to have been lodged on that day.
(c) For the submission to be taken into account, it must be lodged with Customs:
• no later than 50 days after the gazette] day for an application for a TCO;
• no later than 14 days after the gazettal day for an amended application fora TCO; or,
• where the Chief Executive Officer has invited a submission, within the period specified in the invitation.
(d) Every question on the form must be answered.
(e) Where the form provides insufficient space to answer a question, an answer may be provided in an attachment. The
attachment should clearly identify the question to which it relates.
(f) Unless otherwise specified, all information provided should be based on the situation as atthe date of lodgement of the
TCO application.
(g) Customs may require an objector to substantiate, with documentary evidence, information provided in relation to the
objection.
(h) Further information on the Tariff Concession System is available in Part XVA of the Customs Act 1901, in the foreword
to the Schedule of Concessional Instruments, in the administrative guidelines in Volume 13 of the Australian Customs
Service Manual, in Australian Customs Notice No. 98/19, on the Internet at www.customs.gov.au, by e-mailing
[email protected] or by phoning the Customs Information Centre on 1300 363263.
I agree, in submitting this form by electronic means (including facsimile) that, for the purposes of Sub-Section 14(3) of the
Electronic Transactions Act, this submission will be taken to have been lodged when it is first received by an officer of Customs,
or if by e-mail, when it is first accessed by an officer of Customs, as specified in Sub-Section 269F(4) of the Customs Act.
Full Name
Position Held
s47F
Signature
s47F
s47F
Date
4 September 2014
NOTE:
SECTION 234 OF THE CUSTOMS ACT 1901 PROVIDES THAT IT IS AN OFFENCE TO MAKE A STATEMENT TO AN
OFFICER THAT IS FALSE OR MISLEADING IN A MATERIAL PARTICULAR.
WHEN THIS FORM HAS BEEN COMPLETED LODGE IT WITH CUSTOMS BY:
• posting it by prepaid post to the
National Manager, Tariff Branch
Australian Customs Service
Customs House
5 Constitution Avenue
CANBERRA ACT 2601
Or
delivering it to the ACT Regional Office located at
Customs House, Canberra
Or
sending it by facsimile to (02) 6275 6376
Or
• e-mailing it to [email protected]
FOI Document #11
Polyethylene
at a Glance
Oenos
_.
A Bluestar Company
FOI Document #11
AlkadyneTM PE100 Pipe Extrusion Grades
Grade
Melt Index*
(9/10 [email protected] 190'C,
5 00kg)
Density'
Applications
(g'cm')
HDF19313
0.3
0.9610)
High Density black PE100 type resin certified to AS/NZS 4131, for use in pressure pipes and fittings. Excellent low
sag properties and throughput, suitable for the majority of PE100 pipe dimensions.
HDF145B
0.2
0.961(1)
High Density black PE100 type resin certified to AS/NZS 4131, for use in pressure pipes and fittings. Exceptional
low sag properties and throughput, suitable for the most challenging pipe dimensions.
HDF193N
0.3
0.9520)
High Density natural resin for extrusion into a full range of non standard pipe products and as a base for PE100
type striping and jacket compounds.
Notes: (”ASTM D1505/D2839
Alkadyne"PE Pipe Extrusion Grades
Melt Index*
Grade
(g/10 min @ 190.C,
5.00kg)
Densit
y'
iig'crti
Applications
)
MD0898
0.7
0.9520)
Medium Density black PE8OB type resin certified to AS/NZS 4131 for use in pressure pipes and fittings.
MD0592
0.6
0.942')
Medium Density natural resin for extrusion into a full range of non standard pipe products and as a base for PESO
type striping and jacket compounds.
G M7655
0.6
0.9540)
High Density natural high molecular weight resin for extrusion into a full range of non standard pipe products.
MDF169
1.0
0.943)')
Medium Density natural high molecular weight resin for extrusion into a full range of non standard pipe products.
LL0228
1.7(2)
0.9230)
Linear Low Density resin for use in pipe extrusion applications.
Notes: 01 ASTM D1505/D2839
[email protected]°C, 2.16kg
AlkadyneTM PE Wire and Cable Grades
Grade
Melt Index*
(9110 min d 190 C.
2 16kig)
Density'
(igicm)
Applications
MD0592
0.12
0.942(1)
Designed for extrusion into a full range of wire and cable products where natural Medium Density resins are required.
MD0898-1
0.12
0.953(1)
Designed as general purpose jacketing compound for buried wires and cables where abrasion and cut through
resistance is required.
Notes: l')ASTM D1505/D2839
AlkataneHDPE Tape and Monofilament Grades
Grade
Melt Index*
Density#
(g110 min
2.16 kg)
(g)cm)
0.4
GF7740F2
0.950(1)
Applications
Extrusion applications including stretched tape, monofilament, tarpaulins, and over-pouches for medicinal products
Notes: mASTM D1505/D2839
Alkatuff® LLDPE Rotational Moulding Grades
Melt Index
Grade
•
(00 mm @ 190T,
2.16kg)
Density'
(g re 111
Application
LL711UV
3
0.938
Applications requiring excellent ESCR, chemical resistance), stiffness, toughness and UV protection, such as
water and chemical tanks, septic systems and kayaks.
LL705UV
5
0.935
Applications requiring high ESCR, chemical resistance)", toughness, stiffness and high level UV stabiliser, such as
leisure craft, playground equipment and agricultural tanks.
LL755
5
0.935
Applications requiring high ESCR, chemical resistance(1), toughness and stiffness. Incorporation of suitable UV
stabilisation is required for outdoor applications.
10
0.930
High speed intricate applications requiring good ESCR, chemical resistance), toughness and UV protection,
such as consumer goods and playground equipment.
LL710UV
Notes:
" The
level of chemical resistance is a function of product design and environmental conditions. Contact Qenos for further information.
Melt Index according to ASTM D1238 unless otherwise annotated
*
#Density according to ASTM D1505 unless otherwise annotated
FOI Document #11
Additives
Alkathene® LDPE Film Grades
Melt Index*
Grade
(g/10 min @ 190°C,
2.16kg)
Density*
(g/cm')
Applications
Applications
cr
n
Co
co
>,
.5
._
0
8
42
'i
cy
:fc
—i
cu
0
c,
•E
F
l)
v
v
V
v
V
v
V
v
t it'
XDS34
0.30
0.922
Heavy duty sacks, pallet wrap and industrial applications requiring heavy gauge
film. Additive free.
LDF433
0.45
0.925
Heavy duty sacks, pallet wrap and industrial applications requiring medium to
heavy gauge film with increased stiffness.
LDD201
0.45
0.922
General purpose medium to heavy gauge film for heavy duty bags and shrink
film and for use as a blend component.
LDD203
0.45
0.922
General purpose medium to heavy gauge film for heavy duty bags and shrink
film requiring antiblock, and for use as a blend component.
v
LDD204
0.45
0.922
General purpose medium to heavy gauge film for heavy duty bags and shrink
film where a medium level of slip is required.
v
Iv,
v v
LDD205
0.45
0.922
General purpose medium to heavy gauge film for heavy duty bags, frozen food
and produce bags where a high level of slip is required or for use as a blend
component.
v
H
v
LDH210
1.0
0.922
Bundle shrink and other medium gauge film applications such as produce bags,
carry bags and for blending into other film grades.
LDH215
1.0
0.922
General purpose medium gauge film for produce bags and carry bags, frozen
food where a high level of slip is required or for use as a blend component.
XJF143
2.5
0.921
Additive free, general purpose low gauge film for overmap and other
applications and for use as a blend component
LDJ226
2.5
0.922
Bundle shrink, low gauge shrink film and general purpose applications where a
medium level of slip and antistatic are required.
v
LD0220MS
2.5
0.922
High quality low gauge film for lamination and overveap applications where a
medium level of slip is required.
v
to
LDJ225
2.5
0.922
High quality, low gauge film primarily intended for bread bags and overwrap but
also general purpose applications where a very high level of slip is required.
;
r
VH
XLF197
5.5
0.920
High quality, very thin gauge and high clarity film primarily intended for food and
packaging wrap and for drycleaning film. Additive free.
,
v
-2
ii
CO
cm
co
03
'0
E- 2
3 c' 5
v
v
v
v
v
V
v
H
0,_
e
LE
a_
En
.0
ili
2
ut
.
I
8
v
v
v
kr,
v
v
.
v
v
V
v
Notes: Si Based on antistat additive (2) VH = Very High Slip, H = High Slip, M = Medium Slip
Additives
Alkatuff® LLDPE Film Grades
Grade
Melt Index .
I
(gi10 min @ 190C,
2.16kg)
,
Density#
(gr.
Applicati as
Applications
-e
)
imiab
L1_438
0.8
0.922
Heavy duty sacks, agricultural films,lamination and form, fill and seal
packaging where enhanced toughness and sealing characteristics are
desired.
LL501
1.0
0.925
General purpose industrial, agricultural and heavy duty films and as a
blend component to improve film handling in converting and packaging
operations.
LL601
1.0
0.925
General purpose industrial, agricultural and heavy duty films and as a
blend component to improve film handling in converting and packaging
operations.
LL425
2.5
0.918
High quality cast film for applications that require toughness,
high clarity and processability.
Notes: (,) VH = Very High Slip, H = High Slip, M = Medium Slip
*Melt Index according to ASTM D1238 unless otherwise annotated
*Density according to ASTM 01505 unless otherwise annotated
VV
V V V
V
FOI Document #11
Melt Index
Grade
(9110 min @
190°C. 2.16k5)
Density#
(g/cm')
Additives
Appdications
Applications
cy)
co
-a
2
IMO&
ML1810PN
1.0
0.918
Heavy duty bags, industrial and agricultural films, and
form, fill and seal applications and ice bags where
outstanding toughness, searing and hot tack properties
are desirable or for downgauging of existing film
structures.
ML1810PS
1.0
0.918
Heavy duty bags,industrial and form, fill and seal
applications and ice bags where outstanding toughness,
searing, hot tack properties and high slip are desirable
or for downgauging of existing film structures.
ML2610PN
1.0
0.926
ML1710SC.
1.0
0.917
CD
-a
co
co
V
AgriculturalFilm
Alkamax® mLLDPE Film Grades
Co
cY)
V VVVVVVV
V
V
Vt
V
Vt
Vt
Heavy duty bags, lamination, industrial and form, fill
and seal applications where outstanding stiffness,
toughness, optical and sealing properties are desirable
or for downgauging of existing film structures.
V
V
V
V
Vt
Vt
Stretch cling films (with addition of appropriate cling
additive) and other film applications where outstanding
toughness, optical and sealing properties are desirable
or for downgauging of existing film structures.
V
V
V
V
Vt
V
Vt
V
V
V
Vt
V
Vt
Vt
otes: '(VH = Very High Slip, H = High Slip, M = Medium Slip
Alkatane HDPE Film Grades
enera 'u 'Os.
Applications
Melt Index
Grade
(g/10 min @
Density° Applications
(g/cm')
'
2.16kg)
GM4755F
0.10
0.955(1)
Carry bags and liners where high impact, toughness and stiffness are desirable and as a blend component into
LDPE and LLDPE films for heavy duty applications.
HDF895
0.80
0.960 (1)
Moisture barrier and blend component into LDPE and LLDPE films to enhance stiffness. Blend component in core
layer for high clarity coextruded films.
V
V
V
/
/
/
Notes: mASTM 01505/02839
Alkatanem HDPE Blow Moulding Grades
Melt Index*
Grade
(g/10 min @ 190T,
2.16kg)
Density'
(glcml
Applications
HD0840
0.06
0.9530)
Large part blow mouldings, especially blow moulded self-supported drums and tanks (25 - 220 litres).
Exceptional ESCR.
HD1155
0.07
0.9530)
Large part blow mouldings, including 25 litre to 220 litre tanks and drums. Exceptional ESCR.
GM7655
0.09
0.95401
Blow moulded containers including household and industrial chemical (HIC). Suitable for larger part mouldings.
Exceptional ESCR.
GF7660
0.30
0.9590)
Household and industrial chemical (H IC) containers, including detergent and pharmaceutical bottles.
Excellent ESCR.
GE4760
0.60
0.9640)
Blow moulded water, dairy and fruit juice bottles.
HD5148
0.83
0.9620)
High speed dairy packaging applications and other thin walled bottles such as milk, cream, fruit juice and cordial.
Notes: mASTM 01505/02839
Qenos imported polymers and additives
Complementing our Australian manufactured Polyethylene grades, Qenos acts as a local distributor for a wide range of imported polymers and additives including rubbers,
elastomers, adhesives, plastomers, EVA, BOPP Film, EPS, antioxidants and titanium dioxide. For the full Qenos range, please refer to the Qenos website, Customer Service or your
Account Manager.
Melt Index according to ASTM 01238 unless otherwise annotated
*
#Density according to ASTM 01505 unless otherwise annotated
v
FOI Document #11
0
Alkathene'' LDPE Extrusion Coating Grades
Grade
Melt Index
(g,10 min
190 C
2.16kg)
Density#
(gtm
Applications
XLC177
4.5
0.923
Applications including milkboard and fabric extrusion coating where very good drawdown, low moisture vapour
transmission rates and excellent hot tack are desirable. Additive free.
WNC199
8.0
0.918
Liquids packaging and other sensitive food packaging laminates where excellent heat seal, low extractables, good
melt strength and low odour and taint are desirable. Additive free.
LDN248
7.6
0.922
Liquids packaging and other sensitive food packaging laminates where low extractables and low odour and taint are
desirable. Additive free.
LD1217
12
0.918
Liquids packaging and other sensitive food packaging laminates where high line speed, low neck-in, low
extractables and low odour and taint are desirable. Additive free.
•
Melt Index.
•
De(gnsity#
, cm )
Grade
(g/10 min ql; 190 C,
2.16kg)
Applications
XDS34
0.3
0.922
Small part injection moulded caps and closures. Additive free.
WJG117
1.7
0.918
Thick section mouldings, caps and closures, industrial containers where a high level of toughness is desirable.
Additive free.
XJF143
2.5
0.921
Injection moulded caps and dosures, and thick-walled sections. Additive free.
LDN248
7.6
0.922
Injection moulded caps and closures. Additive free.
WRM124
22
0.920
High flow resin for reseal lids, housewares and toys where excellent gloss, low warpage and flow to toughness ratio
are desirable. Additive free.
LD6622
70
0.922
High flow resin for lids and other thin wall injection moulding applications. Additive free.
Alkatuff® LLDPE Injection Moulding Grades
Melt Index'
Grade
LL820
(g10 min @ 190C,
2.16kg)
20
Density'
mg cm )
0 925
Application
Injection moulding and compounding applications such as housewares and lids.
Alkatane" HDPE Injection Moulding Grades
Melt Index*
Density#
Grade
19110 min @19ViC,
2.16kg)
HD0390
4
0.955
Stackable crates for transport, storage and bottles and industrial mouldings where very good mechanical properties
are desirable.
HD0397UV
4
0.955
Mouldings requiring long-term weatherability, including mobile garbage bins, crates, and industrial mouldings where
very good mechanical properties are desirable.
HD0490
4.5
0.955
Stackable crates for transport, storage and bottles, and industrial mouldings where very good mechanical properties
are desirable.
HD0499UV
4.5
0.955
Mouldings requiring long-term weatherability, including mobile garbage bins, crates, and industrial mouldings where
very good mechanical properties are desirable.
HD0790
7
0.956
Industrial pails, crates, closures and sealant cartridges where a good balance between flow and impact resistance is
desirable.
HD1090
10
0.956
Industrial pails, crates, closures and sealant cartridges where a good balance between flow and impact resistance is
desirable.
HD1099UV
10
0.956
Mouldings requiring long term weatherability including industrial pails, crates, and tote boxes where a good balance
between flow and impact resistance is desirable.
HD2090
20
0.956
Housewares, thin-walled containers and closures where excellent mould flow and flexibility is required.
HD3690
36
0.956
Housewares, thin-walled mouldings and closures where excellent mould flow and flexibility is required.
(glcm')
*Melt Index according to ASTM D1238 unless otherwise annotated
Applications
#Density according to ASTM D1505 unless otherwise annotated
FOI Document #11
Qenos Pty. Ltd.
ABN: 62 054 196 771
Cnr Kororoit Creek Road & Maidstone Street,
Altona Victoria 3018, Australia
T: 1800 063 573 F: 1800 638 981
[email protected]
denos.com
ougity
LSO 900,
AJJSTRAIJAN MADE
i51440Ma.
Front Cover: Pellet geometry and pellet quality can have a significant effect on material flow and the efficiency of feeding polyethylene into an extruder. Qenos
measures pellet quality using a pellet shape and size distribution analyser. a device that photographs around 10,000 pellets in 4 minutes, digitally analyses
the images and generates a report on pellet quality. Where a drift in the pellet quality is detected, adjustments are made proactively to maintain high product
integrity.
Rear Cover: The standard for UV performance for PE Water Tanks specified in AS/NZS 4766 PE Tanks for the Storage of Chemicals and Water is 8.000 hours of
uninterrupted exposure to an intense and specifically developed UV light source. Qenos exhaustively tests the long term UV performance of its Rotational Moulding
Resins under conditions of controlled irradiance, chamber temperature and humidity and repeated rain cycles. Alkatuff 711LIV achieves a class leading UV
performance exceeding 20,000 hours against the required standards, ensuring that Alkatuff® 711UV is "Tough in the Sun':
The contents of this document are offered sdely for your consideration and vetification and should not be construed as a warranty or representation for which Oenos Pty Ltd assumes legal liablity, except
to the extent that such liability is imposed by legislation and cannot be excluded. Values quoted are the result of tests on representative samples and the product supplied may not conform in all respects.
Qenos Pty Ltd reserves the nght to make any improvements or amendments to the composition of any grade or product without alteration to the code number. The applications listed are based on the usage
by exisiting Qenos customers. In using Qenos Pty Ltd's products, you must establish for yourself the most suitable formulation, production method and control tests to ensure the uniformity and quality of
your product is in compliance with all laws and your requirements.
Qenos, Alkathene, Alkatuff, Alkamax, Alkadyne and Alkatane are trade marks of Qenos Pty. Ltd.
6th Edition November 2013
Qenos
A Bluestar Company
FOI Document #12
INJECTION
MOULDING
TECHNICAL GUIDE
Alkathene® Alkatuff® AlkataneTM
FOI Document #12
2,7
Front Cover:
Qenos produces injection moulded products for applications
including caps, pails, crates, sealant cartridges, mobile
garbage bins, produce bins, housewares and lids. A full range of
Alkatane HDPE, Alkathene LDPE and Alkatuff LLDPE grades are
available across the Melt Index and density spectrum. In addition,
Qenos distributes a number of speciality polymers suitable for
injection moulding.
Qenos, Alkathene, Alkatuff and Alkatane are trade marks of
Qenos Pty. Ltd.
FOI Document #12
INJECTION
MOULDING
5
FOI Document #12
/z(
5 INJECTION MOULDING
TABLE OF CONTENTS
INTRODUCTION
6
EFFECT OF TYPE OF POLYETHYLENE ON PROCESSING AND PROPERTIES OF MOULDINGS
6
Classification of Polyethylenes
6
MFI
6
DENSITY
7
Effect of MFI and Density on Moulding Characteristics
7
MOULD FILLING
8
Surface Finish
9
Summary
11
EFFECT OF MFI AND DENSITY ON THE PROPERTIES OF POLYETHYLENE MOULDINGS
11
Stiffness
11
Impact Properties
11
Environmental Stress Cracking
13
Mechanical Stress Cracking
14
Summary
14
SOME ASPECTS OF DESIGNING MOULDS FOR POLYETHYLENE
14
Shrinkage of Polyethylene Mouldings
14
Distortion of Polyethylene Mouldings
16
Mould Design
16
Choice of Polymer
17
Moulding Conditions
17
Weld Lines
17
Flow Weld Lines
18
CONDITIONS FOR MOULDING POLYETHYLENE
18
Cylinder and Melt Temperatures
18
Appearance of Mouldings
19
Frozen-in Strain
19
Mould Temperature
19
Injection Variables
20
Injection Pressure and Dwell Time
20
Mould Filling Time
20
Summary
20
2
Qenos Technical Guides
FOI Document #12
INJECTION MOULDING 5
MOULDING FAULTS
21
MOULD RELEASE AGENTS
22
DECORATING POLYETHYLENE MOULDINGS
22
Decorating Untreated Polyethylene
22
Hot Stamping
22
Labelling
22
Embossing
22
Decorating Treated Polyethylene
22
Pre-treatment
22
Flame Treatment
22
Chemical Treatment
22
Tests for Pre-treatment
23
Peel Test
23
Decorating Methods for Treated Surfaces
23
Silk-screening
23
Vacuum Metallising
23
Tests for Finished Coatings
23
Scratch Test
23
Scotch Tape Test
23
APPENDIX 1 - FROZEN-IN STRAIN
24
APPENDIX 2 - INJECTION MOULDING TROUBLESHOOTING GUIDE
25
BIBLIOGRAPHY/FURTHER READING
27
Qenos Technical Guides
3
FOI Document #12
FOI Document #12
INJECTION MOULDING 5
INTRODUCTION
The purpose of this document is to provide an
introduction to the processing of polyethylene by
injection moulding. The effects of Melt Flow Index (MFI)
and density on moulding characteristics and on the
properties of the finished moulding are discussed, in
the light of which, recommendations are made as to the
desirable values of these two factors for stressed and
unstressed applications.
Mould design is considered with special reference to
questions of shrinkage and distortion and examples are
(ill given to illustrate these points. The moulding process
\
,
itself is discussed in some detail, guidance being given on
all the operations which have to be carried out. Moulding
faults, causes and remedies are also summarised.
Disclaimer
All information contained in this publication and any further information, advice, recommendation or assistance given by Qenos either orally or
in writing in relation to the contents of this publication is given in good faith and is believed by Qenos to be as accurate and up-to-date as possible.
The information is offered solely for your information and is not all-inclusive. The user should conduct its own investigations and satisfy itself as to
whether the information is relevant to the user's requirements. The user should not rely upon the information in any way. The information shall not
be construed as representations of any outcome. Qenos expressly disclaims liability for any loss, damage, or injury (including any loss arising out of
negligence) directly or indirectly suffered or incurred as a result of or related to anyone using or relying on any of the information, except to the extent
Qenos is unable to exclude such liability under any relevant legislation.
Freedom from patent rights must not be assumed.
Qenos Technical
Guides
5
FOI Document #12
5 INJECTION MOULDING
INTRODUCTION
Injection moulding is one of the most widely used
processes for converting thermoplastic raw materials
into finished products. Fundamentally, a solid polymer is
plasticated into a molten mass via thermal and frictional
heating and once a suitable volume of melt has been
produced, the polymer is injected into the mould to form
the finished part (see Figures 1 and 2).
Ejector
Pins
Cavity
However, this very ease of processing often leads to the
use of moulding conditions which are not the most suitable
for producing the finished part. Also, because almost all of
the many different types of polyethylene can be moulded
on standard equipment, the polyethylene type that is most
suitable for a particular application is not always chosen.
EFFECT OF TYPE OF POLYETHYLENE ON
PROCESSING AND PROPERTIES OF MOULDINGS
To obtain polyethylene mouldings which will withstand
long and arduous service two important questions must
be answered:
Plastic
Granules
Nozzle Cylinder
a. Which type of polyethylene should be used?
b. What are the correct moulding conditions?
Mould
Melted
Plastic
crew
otor
Drive
To do this it is necessary to know how the different types
of polyethylene used for injection moulding differ from each
other: first, in the way in which they are processed and
second, in the physical properties of the moulded article.
Classification of Polyethylenes
Figure 1: Schematic Representation of an Injection
Moulding Machine
The most important variables which characterise a
polyethylene are its Melt Flow Index (MFI) and density.
Melt Flow Index (MFI)
SO.00O
7.220.033
0 men
Viscosity
— poises
zi go=
elow/e4O0m. •
104444•01 P.m Met
00.*•00.
•
Number
avergae
molecular
weight
(7)
o
,00
2
lo
02
Injection Moulding is fundamentally simple, easy to operate
and is capable of producing a very wide variety of industrial
and domestic articles. Of all thermoplastics, polyethylene
is one of the easiest to injection mould. The resin flows
easily into difficult cavities, its viscosity changes smoothly
as the melt temperature increases and it can be processed
over a wide temperature range without decomposition.
6
30.002
20 020
>
Figure 2: Finished Moulded Part including Sprue
Injection Point
40,033
07
20
7.)
200
NUMBER AVERAGE MOLE CULAR WEIGHT
MFI is a measure of melt viscosity at low shear rates and
is defined as the weight in grams of polyethylene extruded
in 10 minutes from a special plastometer under a given
load at 190°C. Thus, a low MFI corresponds to a high melt
viscosity. Figure 3 shows how the MFI is related to the
number average molecular weight of the polymer.
MELT FLOW INDEX
Figure 3: Relation between MFI (g/10 min) and
Number Average Molecular Weight
Qenos Technical Guides
FOI Document #12
INJECTION MOULDING 5
DENSITY
Density is related to the crystallinity of the polyethylene
and is measured in g/cms.
Because polyethylene molecules are long and contain
branches, complete crystallisation cannot take place
when polyethylene is cooled from the molten state, and
amorphous regions occur between the crystallites. The
smaller the number of branches, the more crystalline
the polyethylene will be and the higher its density.
Although MFI and density are the most important variables
which characterise a polyethylene, it must be emphasised
that all polyethylenes with the same MFI and density are
,
,,, not necessarily identical. Each polyethylene producer has
(.____)
1 specific manufacturing processes and by varying reactor
conditions it is possible, while maintaining a constant
MFI and density, to alter various features of the polymer
such as the molecular weight distribution and the degree
of long and short chain branching that cause changes
in the processing behaviour and the physical properties
of the polymer.
FILLING
CYCLE
COOLING
CYCLE
2
(J
Characteristics
The injection moulding process is shown diagrammatically
in Figures 4 and 5. For any given machine and mould,
the MFI and density of the polyethylene will considerably
affect the injection dwell and cooling times in the cycle.
The injection time is not significantly affected and the
mould opening, extraction, and mould closing times are
not affected by the MFI or density of the polymer.
Injection time
Moulding
extracted
Mould
opening
Polythene
under pressure
Injection
dwell time
Ram withdraws
Figure 4: Injection Moulding Cycle
Qenos Technical Guides
As far as the polyethylene is concerned the output of any
injection moulding machine depends predominantly on
two factors:
• The time taken for the polyethylene to reach moulding
temperature
Effect of MFI and Density on Moulding
Mould closing
Ram begins to
move forward,
Figure 5: Pictorial Representation of the Injection
Moulding Cycle
Cooling
time
• The time taken for the polymer to be cooled sufficiently
in order for the moulding to be removed.
A convenient method of assessing the effect of different
types of polyethylene on output rate is to plot the number
of mouldings which can be made in one hour against the
cylinder temperature used. Although the design of the
mould and the type of machine affect output greatly, for
any given mould on a particular machine an output curve
can be obtained by finding for each cylinder temperature
the fastest possible cycle which gives mouldings
acceptable in all respects except for that of surface gloss,
i.e. the minimum injection dwell time, pressure, and cooling
time have been used. A typical curve for a plunger machine
is shown in Figure 6. It will be noticed that, at first, as
the temperature increases the output also increases.
The reason for this is that at low temperatures a long cycle
is necessary to melt the granules thoroughly, but as the
temperature increases, the melting time becomes shorter
and therefore the cycle is also shortened. A point is soon
reached, however, when the time taken to melt the
granules is no longer the limiting factor. The greater
parameter of importance is then the time taken for the
mouldings to cool to a temperature at which they can be
extracted easily from the mould. Beyond this point, as the
melt temperature increases the cycle time has to be
extended and the output consequently falls.
7
FOI Document #12
I/9
5 INJECTION MOULDING
To use injection moulding machines most efficiently, the
cylinder temperature should be chosen so that the output
is at its peak. There are, however, two factors which
frequently prevent this being done, namely, the necessity
to fill the mould, and the desire to obtain mouldings with
a good surface finish. These factors are discussed below.
LIMITED BY RATE
OF CODUNG
/ATE
TICISATION
70
MOULD FILLING
00
50
170
110
210
250
250
270
293
CYLINDER TEMPERATURE — °C
Figure 6: Variation in Output Rate of Mouldings with
Cylinder Temperature
Figure 7 shows the effect of density on output rate for
polyethylenes of the same MFI. It indicates that the higher
the density, the higher the output rate on the cooling side
of the curve at any given cylinder temperature. The reason
for this is that mouldings of higher density can be extracted
from the mould at higher temperatures because they are
more rigid at these temperatures than are mouldings of
lower density. The higher density materials, however,
require higher cylinder temperatures to produce adequate
melting of the granules, particularly if the amount of
material being handled is near the plasticising capacity of
the machine, and the use of such temperatures may slow
down the output rate.
In practice, there are some moulds for which it is not
possible to draw an output curve over the whole range
of cylinder temperatures because the mould cannot be
filled at the lower temperatures. Therefore, the moulding
temperature which has to be used is the lowest
temperature at which the mould can be filled, and this
may restrict the output. In order to attain as close to the
maximum theoretical output, good mould filling properties
are obviously desirable in a polyethylene.
The spiral flow test was devised to assess the mould
filling properties of materials. It involves the measurement
of the length of spiral obtained when moulding under
standard conditions using the special mould shown
in Figure 8. In order to compare different types of
polyethylene the cylinder temperature, mould temperature,
cycle time, injection speed and pressure are all held
constant, and under these conditions the length of spiral
obtained gives a good comparative evaluation of the mould
filling properties of the polyethylenes being used.
Figure 8: Spiral Flow Mould
Figure 9 shows that the main factor which influences ease
of mould filling is MFI. Although density undoubtedly has an
effect on the spiral flow length, for polymers with constant
MFI this effect is relatively small.
Figure 7: Effect of Density on Output Rate for Polymers
of the Same MFI
8
Qenos Technical Guides
FOI Document #12
77'
INJECTION MOULDING 5
20
SPIRAL FLOW LENGTH —
cm.
CONSTANT DENSITY
0
II
51
lz/
lue
ON
LENGTHOF S PIRAL -
320
me
DX
.
...
0 I/
zr.....
..,
300
572
IP,/
70
/
/
/
2
2E0
.
00
/
536
52°
230
NO
so 2
7
40
/
240
466
i•
MELT FLOW INDEX
421
220
/7
Figure 9: Effect of MR on the Mould Filling Properties
of Polyethylenes of Constant Density
A feature of the spiral flow test is that it can be applied to
all injection moulding materials. Figure 10 shows a chart
on which the spiral flow length has been plotted against
a series of cylinder temperatures for a range of polymers.
For most materials the temperatures used range from
the lowest at which a readable flow length can be obtained
to the highest that can be used without degrading the
material. However for polyethylenes of high MFI, with the
particular equipment used, the upper temperature was set
by the first observance of "flashing" (thin films of excess
polymer) on the moulded part.
KO
312
NO
366
—
Low.oeNsrry POLYTHENES
-- GP POLYSTYRENE
- POLYPROPYLENES
- NYLON
HIGH.DENSITY POLYTHENE
(Typlul 1216c5on mou/dIng gado)
4
%a
320
215,
140
PLUNGER PRESSURE: 20000 MAO
(1403 554c6. 1)
504.
0
10
40
50
00
SPIRAL FLOW LENGTH — in.
Figure 10: Spiral Flow Curves for some Typical
Thermoplastics
Surface Finish
The second factor which may prevent moulding being
carried out at the peak of the output curve is the
requirement to obtain a good surface finish on the
moulded article. It can be seen from Figure 11 that the
gloss of a polyethylene moulding improves with increasing
cylinder temperature and that mouldings produced at the
lower temperatures have 'chevron' marks or rings on the
surface (see Figure 12). When mouldings with an even,
glossy surface are required it may be necessary to mould
at a cylinder temperature which is higher than that which
corresponds to the fastest output rate.
Qenos Technical Guides
9
FOI Document #12
/17
5 INJECTION MOULDING
110
OUTPUTRATE - NUMBEROFMOULDINGSPERHOUR
100
90
210
70
LIMITED BY RATE
OF PLASTICISATION
ao
Figure 12: Photo Illustrating 'Chevron Rings on an
Injection Moulded Surface
so
LIMITED BY RATE
OF COOLING
40
Mf1 20
30
110
150
170
190
210
230
50
270
290
Figure 11: Variations of Surface Gloss of Mouldings with
Cylinder Temperature
Gloss is assessed both visually and by measuring the
light reflected from the surface of mouldings made
under standard conditions. By the latter method, gloss/
temperature curves can be plotted as shown in Figure 13.
This not only shows the effect of cylinder temperature on
gloss, but also the very marked effect of MFI. With a higher
MFI, high-gloss mouldings can be produced at a lower
cylinder temperature which allows for a faster output
(see Figure 13).
10
UNITSOFGLOSS
CYLINDER TEMPERATURE —°C
MF1 2
1' 140
150
50
220
240
293
CYLINDER TEMPERATURE — °C
Figure 13: Effect of M Fl and Temperature on Gloss
Qenos Technical Guides
FOI Document #12
INJECTION MOULDING 5
Summary
It can be concluded that a high MFI is the characteristic
mainly responsible for ease of moulding and high
output rates. The higher the MFI, the lower the cylinder
temperature which can be used to obtain adequate mould
filling and acceptable surface finish, and consequently, in
most cases, the higher the output will be. For resins with
a constant MFI, the degree to which an increase in density
leads to higher or lower outputs will depend mainly on the
size of the moulding in relation to the size of the machine.
For adequate melting of the granules, higher density
polyethylenes require higher cylinder temperatures than
do the lower density polyethylenes, and melting is more
likely to be a limiting factor.
Thus, as far as processing is concerned, the type of
polyethylene chosen should have as high an MEI as
possible. However, the choice of both MFI and density
must also take into account the physical properties
required in the finished moulding, and this subject is
discussed in the next section.
EFFECT OF MFI AND DENSITY ON THE
PROPERTIES OF POLYETHYLENE MOULDINGS
The physical properties of polyethylene which are of
particular importance in injection moulded articles are:
• Stiffness
• Impact properties
• Resistance to environmental stress cracking
• Resistance to mechanical stress cracking
Stiffness
The main factor determining the stiffness of a moulding
is the density of the polyethylene. Figure 14 shows
how the stiffness (as measured by the 100 sec tensile
modulus) increases rapidly with increasing density. In
the lower density range a change in density of as little
as 0.007 g/cm3 will double the stiffness. Figure 14 also
shows the effect of temperature on stiffness.
MFI has virtually no effect on stiffness.
Qenos Technical Guides
..,
1
130 120 -
206C
IV) 100
93 -
7o es so
44 SO
30 20
10
0
o'c
WC
ICC
100T
Figure 14: Variation of Stiffness and Density
with Temperature
Impact Properties
One of the outstanding properties of low density
polyethylene is its toughness; when subjected to impact it
will stretch and cold-draw before it breaks, rather than fail
in a glass-like manner. On the other hand, medium and
high density polyethylenes can fail in a way that is unknown
in low density polyethylenes. This type of failure is known
as brittle failure. It is quite different from the tough failure
of low density materials and is particularly noticeable in
mouldings which have sharp notches or scratches on
the surface. The usual impact tests for plastic materials
are difficult to apply to both brittle and tough types of
polyethylene and therefore a special test had to be
devised. For this an impact machine is used (see Figure 15)
in which small specimens (lx lx 0.16 cm) are notched
to a depth of 0.020 cm and subjected to a blow from a
pendulum. The energy lost by the pendulum in striking the
specimens is termed the impact energy, although much
of this energy is expended in bending the specimen as
the pendulum swings past it. Polyethylene specimens are
rarely broken by the first blow, and therefore after a short
rest period they are given a second blow. The energy
absorbed by this second blow, expressed as a percentage
of the energy absorbed by the first blow, is termed the
fracture resistance. This quantity is found to be a useful
measure of the amount of damage caused by the first blow.
11
FOI Document #12
5 INJECTION MOULDING
Impact energy and fracture resistance depend on both
MFI and density, as may be seen from Figure 16. For some
polyethylenes the impact energy may increase at first with
increasing density and then decrease. This initial increase
in impact energy is due to the contribution from the energy
used in bending a specimen of increased stiffness.
Ultimately, however, the increase in density trends towards
brittleness, which becomes the dominant factor and
results in the measured impact energy falling to very low
levels. It can be seen quite clearly that in order to avoid
brittleness the higher density polyethylenes must have
a low MFI. Consequently, if toughness is required in the
higher density polyethylenes, poorer processability,
poorer mould filling and, in general, higher processing
temperatures will be required. It can also be seen that
with polyethylenes of lower density, a much wider choice
of MFI is possible without sacrificing toughness.
The dependence of brittle failure on density is also
complicated by the fact that the density of any polyethylene
is affected by its rate of cooling from the molten state.
This effect is illustrated opposite in Table 1.
Values for densities quoted in the literature usually refer
to specimens prepared in a standard way involving slow
cooling. In injection moulding, however, the polyethylene
is cooled rapidly and the molecular chains have no time
in which to pack into their equilibrium positions and
consequently the density is reduced to below the
equilibrium value. Subsequently, overtime, the density
increases towards its equilibrium value, a process which
is very slow but which is accelerated at elevated
temperatures. Provided that a polyethylene is chosen with
a density and MFI such that the polyethylene, when cooled
at the slowest rate found in injection moulding, lies in the
'tough' region in Figure 16, no detrimental change to the
mouldings impact strength will arise. But if a polyethylene
in the 'brittle' region is chosen (for example, a material
with a MFI of 20 g/10 min and a density greater than
0.927 g/cm3) mouldings produced under conditions of
rapid cooling will appear to be tough initially, because
of the decrease in density, but may become brittle as the
density increases overtime.
Figure 15: Impact Machine Showing Sample Holder and
Process of Use
12
Qenos Technical Guides
FOI Document #12
//t
INJECTION MOULDING 5
Table 1: Effect of Cooling Rate on the Density of Polyethylene (MFI 20)
Density g/cm3
Cooling Rate
Annealed at 140°C and cooled at 5°C per hour
0.918
0.923
0.927
Annealed at 140°C and cooled at 30°C per hour
0.916
0.921
0.925
Fast cooled in injection moulding
0.913
0.919
0.922
1000
—
_
,—
120
,L--
CONSTANT DENSITY
'BRITTLE'
_
—
MELTFLOW INDEX
10
E:
—
'TOUGH'
FRACTURE
RESISTANCE
E.
7
_
209
—
9-1
EE
=
—
—
—
001
OM
091
092
093
091
Figure 16: Variations in the "Tough Brittle" Transition
(as defined by fracture resistance contours at 40% and
20%) with MFI and Density
Environmental Stress Cracking
Environmental stress cracking is the name given to a
phenomenon by which polyethylene under high stresses
may crack in contact with certain active environments
such as detergents, fats and silicone fluids.
The resistance of polyethylene to environmental stress
cracking decreases rapidly as the MFI is increased.
Figure 17 indicates how test specimens of polyethylenes
of different M Fl and of constant density behave when
subjected to a severe stress in the presence of an active
environment. Comparison of polyethylenes of constant
MFI but of different densities is more complicated because
in such tests the specimens are tested under constant
strain and therefore the higher density polyethylenes
will be under greater stress because they are stiffer.
Nevertheless, the comparison is a valid one because in
many applications, for example, screwing down a bottle
closure or forcing a washing-up bowl into a sink, it is the
deformation which is constant rather than the stress.
Qenos Technical Guides
7
OA
DENSITY AT 23°C. — g./c.c.
20
MELT FLOW INDEX
Figure 17: Resistance of Polyethylenes of Different MFI
to Environment Stress Cracking
In practice it is important that high MFI polymers, even
of low density, should not be used for applications in
which they will be severely stressed when in contact with
active environments. For such applications a polyethylene
of low MFI is essential and the higher the density of the
polyethylene the lower the MFI must be.
A typical application for which a polyethylene of low MFI is
preferred in order to reduce the hazards of environmental
stress cracking is that of closures used in contact with
liquid detergents, soap solutions and certain cosmetics.
It is important however not to exaggerate the seriousness
of environmental stress cracking. It has been found that
the majority of mouldings made from polyethylene are not
subjected to severe enough stressing in service to cause
failure, even though they may be in contact with active
environments. For example, most polyethylene housewares
are in daily contact with both detergents and fats, and yet
the externally applied stresses to which they are subjected
to are not sufficient to cause failure through environmental
stress cracking.
13
FOI Document #12
/10
5 INJECTION MOULDING
Careful consideration needs to be made of the choice of
polymer that will meet the demands of the finished product
and the environment(s) that it will be exposed to (e.g. oils,
fats, alkalis, acids and temperature, etc.). To make the best
resin selection, customers are advised to discuss their
specific end product requirements with their Qenos
Technical Service Representative.
Mechanical Stress Cracking
Under certain conditions the moulding process itself
can create high levels of internal stress in polyethylene.
This is due to the semi-crystalline nature of the polymer
which enters the mould in a molten state and undergoes
crystallisation as the resin solidifies. The different
polyethylenes undergo different degrees of crystallisation
which is dependent on their molecular structure.
In general, the polyethylenes can be ranked in terms of
their crystalisability/shrinkage in the following order:
HDPE ?_ LLDPE LDPE
The internal stress that is also commonly referred to as
'frozen in strain' or 'residual strain' may cause similar
effects to those seen where polyethylene is exposed to
external stresses in service.
The occurrence of 'frozen in strain' is due to both the
crystalline nature of the resins used and also as a result of
the moulding conditions and the design of the finished part
(see Conditions for Moulding Polyethylene section on pg. 18).
Once a polyethylene has been selected (HDPE, LLDPE,
LDPE) for fabrication of the finished part, internal stresses
can be negated/minimised through careful mould design
and by controlling the processing conditions on the
injection moulding machine.
Many mouldings, however, are also subjected in service
to externally applied mechanical stresses which can cause
cracking. Examples of such mouldings are those containing
metal inserts (e.g. knobs) and those used for interference
applications (e.g. snap-on closures, ferrules or feet for
tubular furniture). For such finished parts careful selection
of the polymer is important. Within the polyethylenes a
balance is required between the MFI (e.g. for ease of
processing) and the density (e.g. which affects the level of
shrinkage) in order to minimise the level of internal stress.
Generally, higher density polyethylenes would require a
lower MFI and vice versa. For example, a polyethylene
of MFI 20 g/10 min should generally not exceed a density
of 0.918 g/cm3. Although such "rules of thumb" are only
14
general recommendations, other considerations of mould
design and the generation of weld lines in the finished part
are factors that need to be reviewed when assessing the
strength of the moulding.
For articles not expected to be stressed in service, cracking
caused by 'frozen-in strain' is the hazard to be avoided.
A polyethylene of higher MFI is preferable because it is
easier to mould such a polyethylene to give a low level of
'frozen-in strain'.
Summary
In general, polyethylenes of high MFI and low density
are most commonly used for injection moulding because
they give the highest outputs, have the best mould
filling properties, and give the glossiest mouldings. For
applications in which mouldings are likely to be stressed
in service, polyethylenes of low MFI must be used. If
increased stiffness is required, polyethylenes of higher
density are necessary, but these must have a lower MFI
to prevent them from becoming brittle and to improve
resistance to environmental and mechanical stress
cracking. For non-stressed applications 'frozen-in strain' is
the hazard to be avoided and a polyethylene of higher MFI
is preferred. Provided that these few simple principles are
followed, articles giving a long and satisfactory service
life can be moulded from polyethylene without difficulty.
SOME ASPECTS OF DESIGNING MOULDS
FOR POLYETHYLENE
A detailed examination of mould design is outside the
scope of this booklet. There are however, three problems
affecting mould design which, although not peculiar to low
density polyethylene, occur frequently with this material
and which can conveniently be discussed here. These are:
• Shrinkage
• Distortion
• Weld lines
Shrinkage of Polyethylene Mouldings
The influence of moulding conditions and the shape
of mouldings is so great that it is almost impossible to
predict the exact shrinkage of polyethylene mouldings.
It is recommended therefore that trials under controlled
moulding conditions should be carried out before the
mould is hardened and polished. The mould may then be
adjusted accordingly. To allow for any after-shrinkage the
dimensions of mouldings should not be checked until at
least 24 hours after removing the mouldings from the mould.
Qenos Technical Guides
FOI Document #12
if
INJECTION MOULDING 5
Measurements must be checked in all important
dimensions because mould shrinkage varies with the
direction of flow, and checking only one dimension and
applying proportional corrections to the others may lead
to major inaccuracies.
The following major variables affect mould shrinkage.
• Melt temperature: the higher the melt temperature,
the greater the shrinkage will be
• Mould temperature: the higher the mould temperature,
the greater the shrinkage will be
• Injection dwell time and injection pressure: shrinkage
will be smaller for longer injection dwell times and higher
pressures
• Thickness of section: the thicker the moulded section,
the slower the cooling and the greater the contraction of
the moulding will be
As Designed
As Molded
• Orientation: shrinkage will be greater in the direction
of flow than at right angles to it
• Density: shrinkage is greater with polyethylenes of higher
density e.g. a polyethylene of density 0.930 g/cm3 will
shrink more than a polyethylene of density 0.918 g/cm3
Boss in corner
causes sink
Thinner walls on boss,
eliminates sink
• Gating: shrinkage is usually greater when pin gates are
used than when sprue gates are used
Because the above variables have such a marked effect
on shrinkage, it is clear that in order to maintain accurate
dimensions, close control of moulding conditions is
essential. Cooling channels must provide adequate and
even control of mould temperature over the whole mould.
Cycle time control is of equal importance, especially for
precision work. Injection pressures should be controlled
and the values checked regularly on a gauge.
A point which must always be kept in mind when
specifications call for close moulding tolerances is that
the coefficient of thermal expansion of polyethylene is high
and that a change of 5°C in room temperature will alter the
length of a moulding by as much as 0.001 cm/cm.
Thick walls
causes sink, warp
& excess shrink
Thinner walls give
accurate parts
Some examples of shrinkage are illustrated in Figure 18.
Because it is usually on small mouldings that close
dimensional control is required, Figure 18 shows where sink
marks and warping are likely to occur in such finished items.
Qenos Technical Guides
Figure 18: The Effects of Processing Conditions on
Shrinkage and Warping
15
FOI Document #12
/8
5 INJECTION MOULDING
Distortion of Polyethylene Mouldings
Distortion or warping of polyethylene mouldings can
be a problem on flat articles which do not have a solid
rim or walls to keep the base firmly held in position.
The explanation of this warping is mainly due to polymer
orientation and differential crystallisation across the
moulding (see Figure 19).
Figure 19: Processing Conditions Causing Polymer
Orientation which Leads to Warping
When the mould is first filled, a hot moulding will be
made. As the mould fills, the long thread-like polyethylene
molecules would tend to be oriented in the direction of
flow i.e. radially outwards, but as the moulding cools a
radial shrinkage will occur which is greater than the
shrinkage at right angles to the radius. Thus when the
moulding is cold it will inevitably warp due to the difference
in the stresses generated in the part. All methods of
preventing the distortion of flat articles without rims or
walls depend, in essence, on reducing this difference.
Sprue
Mould Design
To reduce the warping in articles, multiple pin gates must
be used. This system relies on reducing the length of each
radial flow path and inter-mingling the melt streams, and is
often adequate for low and medium density polyethylenes
(see Figure 20).
Fan Gate Runner
Parting Line
Product
Figure 20: Photos Illustrating Multiple Pin Gating
and Fan Gating
16
Qenos Technical Guides
FOI Document #12
/Io
INJECTION MOULDING 5
For rectangular shapes the ideal gating arrangement is
a fan gate (see Figure 20) all along one edge so that flow
takes place mainly along the major axis. The moulding
will still shrink to a greater extent in the direction of flow,
causing the major axis to be proportionately shorter than
the minor axis when the moulding is cold, but it will not
distort. To position a gate at the end of a rectangular
article is relatively easy on small mouldings to be made
on multi-impression tools, but it is not so easy on large
single-impression moulds. Some machine manufacturers
can arrange for off-set injection points by altering the
nozzle position from the usual central point and this is
a very useful feature if large flat articles are to be made
from high or low density polyethylene.
Weld Lines
Choice of Polymer
Figure 21: Mouldings Illustrating the Formation of
Weld Lines When Two Melt Fronts Meet
The likelihood of warping increases rapidly with increasing
density of the polyethylene used: high density polyethylene
mouldings warp more than those of medium density, which
in turn warp more than those of low density polyethylene.
If flexibility in the moulding can be tolerated, a polyethylene
of low density (e.g. 0.916 g/cm3) will give the least
distortion. If the mouldings are not to be stressed and
physical strength is not important, e.g. sink trays and many
box lids, the best results are obtained from a low density
polymer of high MFI (22-70 g/10 min, according to the lack
of strength which can be tolerated).
Moulding Conditions
Obviously the ideal moulding conditions would be those
which give no orientation in the moulding and thus no
warping. In practice such conditions can never be
achieved. It has been found that long injection dwell
times and high pressures, because they reduce the overall
level of shrinkage, can often reduce warpage, but these
conditions give rise to packing stresses and may cause the
mouldings to split across the sprue. The best compromise
in moulding conditions has been found to consist of a very
high melt temperature (i.e. 50°C higher than that normally
used for a given polyethylene) and a very cold mould (i.e. as
cold as can be achieved).
Qenos Technical Guides
Weld lines can occur in any plastic moulding when the
melt stream is divided as it flows round some obstruction,
or can arise through non-uniform filling of the mould caused
by, for example, eccentricity of cores (see Figure 21).
Weld lines are particularly troublesome in polyethylene
mouldings which are stressed in service, because failures
are likely to occur some considerable time after the part
has been installed. With many plastics, weld lines are
immediately obvious as a physical weakness in the
moulding which is detectable by brittleness on impact
or flexing. With polyethylene, the fault may not appear
so serious, and it may only be when stress is applied over
a period of time in service, particularly in contact with
an active environment, that failure will occur. Weld lines
can be minimised by the use of high melt and mould
temperatures, and also by utilisation of high injection
pressures. Although care must be taken not to create
greater difficulties by introducing packing around the sprue.
A better solution however is to avoid weld line formation
wherever possible by suitable positioning of the gate. On
many bottle closures for example a centre pin gate can be
used instead of a side gate. The mould may cost more with
centre gates, but with bottle caps in particular, which are
stressed in an outwards direction, the advantages of
mouldings free from weld lines are great. In many cases
the additional strength conferred by centre gating will
permit the use of a polyethylene of high MFI which,
although poorer in resistance to environmental stress
cracking, will process easier and faster. Where articles
of cylindrical shape are highly stressed in an outwards
direction and centre gating is not possible, serious
consideration should be given to diaphragm or ring gating.
17
FOI Document #12
5 INJECTION MOULDING
Flow Weld Lines
These generally occur towards the end of the flow path
on a thin-walled article of large surface area, e.g. certain
types of buckets. They are caused by the dividing of the
advancing melt front into separate streams which fail
to fuse together when the mould is full. This effect is
aggravated by inadequate pressure on the melt or too low
a melt temperature. The weld lines formed may be barely
visible to the naked eye, but they can readily be detected
by immersing the moulding in carbon tetrachloride at a
temperature of 50 to 70°C where fissures will open up.
Such weld lines are quite common and cause splits in the
walls of thin containers (see Figure 22).
The aim of the moulder must be to choose, for each
particular material and moulding, the correct combination
of variables which will produce perfect mouldings as easily
and as quickly as possible. The position is somewhat
complicated by the fact that a moulding that looks perfect
may not in fact be so because of the presence of 'frozen-in
strain', and therefore the choice of moulding conditions
must take into account their effect, not only on the
appearance of the moulding, but also on 'frozen-in strain'.
In the following sections each variable will be discussed in
the light of these two considerations, together with other
relevant factors, such as the use of mould release agents.
Finally a table, summarising some common moulding faults,
their causes and remedies, is given (see Appendix 2).
Cylinder and Melt Temperatures
soy.WIIIIIIIIM
28 I 43
1.
56' 8 16
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U Figure 22: Failure Due to Flow Weld Lines
CONDITIONS FOR MOULDING POLYETHYLENE
In the injection moulding process the moulder is able to
control several operating variables, each of which can
influence the quality of the mouldings or the rate at which
they are produced. These variables are:
• The temperature of the machine cylinder
• The temperature of the mould
• The 'injection variables', i.e. the injection pressure
and speed, and the cycle time
18
The melt temperature is the temperature of the
polyethylene as it enters the mould. Depending on
the grade of polyethylene being used, the temperature
should lie in the range 160-280°C. In practice, it is not
convenient to measure the melt temperature directly,
and it is therefore necessary to use the machine cylinder
temperature as a guide to the value of the melt
temperature. The important point to note is that the
cylinder temperature as indicated on the control panel
instruments is not necessarily the same as the melt
temperature, because the melt temperature depends on
the rate at which the material passes through the cylinder
and through the gate of the mould, as well as on the
cylinder temperature. For example, if the shot weight is
almost as large as the shot capacity and mouldings are
being produced very rapidly, the material will be in contact
with the heated cylinder for only a short time before being
injected and may not have time to reach the temperature
of the cylinder but may be as much as 30°C lower. On the
other hand, in a machine of larger capacity that is working
at slower output rates, the time of contact will be longer
and consequently a lower cylinder temperature can be
used and the difference between it and the melt
temperature can be reduced to about 5°C. Similarly, a
moulding containing a thick section will require a lower
cylinder temperature than will a moulding of equal weight
but of thinner section. This is because the thick moulding
will require a longer cooling time and thus a longer cycle
time than the thinner moulding; therefore the material will
be in contact with the heated cylinder for a longer time
and its temperature will more nearly approach that of the
cylinder. A less common cause for the melt temperature
to be different from the cylinder temperature is frictional
heating of the material as it passes through the gate;
Qenos Technical Guides
FOI Document #12
/of
INJECTION MOULDING 5
if material is injected rapidly through a small gate the heat
generated may be sufficient to raise the melt temperature
above that of the cylinder.
From these examples it is clear that it is not possible to
predict the exact cylinder temperature that must be used
to obtain a given melt temperature, but that it is necessary
to choose a suitable cylinder temperature as a starting
point and then to make adjustments based on visual
inspection of the mouldings and on considerations of
'frozen-in strain'. For grades with MFI above 20 g/10 min
the suggested starting temperature is 210°C and for
grades with MFI below 20 g/10 min the suggested starting
temperature is 260°C.
When the cylinder temperature has been set, the injection
pressure and cycle time should be adjusted to the minimum
values consistent with the production of full mouldings,
and moulding should then be carried out for long enough
(usually 15-30 minutes) to enable conditions to settle down.
The mouldings should then be inspected and tested. Testing
should be conducted after conditioning for 24 hours,
preferably in a constant temperature environment.
Appearance of Mouldings
If the surface of the mouldings is dull or patchy, or contains
matt rings or 'chevron marks' (see Figure 12), this is an
indication that the melt temperature is too low, and the
cylinder temperature should be raised until mouldings with
a uniform, glossy finish are obtained. If the surface finish
is acceptable, but mouldings are tending to stick in the
mould, the melt temperature is probably too high and the
cylinder temperature should be reduced until the trouble
is eliminated. These procedures are effective for all grades
of Alkathene LDPE but it should be remembered that with
materials of MFI below 0.5 g/10 min the cycle time may
have to be rather long to allow the melt to reach the
required temperature.
Frozen-in Strain
At low moulding temperatures the melt viscosity is higher,
the mould fills relatively slowly, and the polyethylene
freezes quickly so that relatively little relaxation of the
polymer orientation can occur. It has been shown quite
conclusively, not only by laboratory tests but also by
extensive service trials, that mouldings made at low melt
temperatures can contain enough 'frozen-in strain' to
overcome the structural integrity of the part and result in
failure, whereas those made under optimum conditions are
perfectly satisfactory (see Figure 22).
It may be concluded that the optimum cylinder temperature
is the lowest at which full, glossy mouldings can be
obtained, and that under these conditions 'frozen in strain'
will be at a minimum. Too high a temperature will lead to
sticking and long cycles, and too low a temperature will
lead to strained mouldings.
Mould Temperature
The mould temperature chosen should be that at which
good mouldings can be produced with a minimum cycle
time. The colder the mould the faster the melt will cool
and the greater will be the tendency for 'frozen-in strain'
to develop. Therefore, to reduce 'frozen-in strain' a warm
mould is recommended and for the minimum amount
of strain, a heated mould (as hot as possible) would be
required. However, the use of a very hot mould would slow
down the cooling rate and thus not only prolong the
moulding cycle but also substantially increase the density
of the moulding. This is particularly true for mouldings
that contain thick sections. As explained in the Impact
Properties section (pg. 11), certain polyethylenes can,
under these conditions, be brought from the tough region
into the brittle region (see Figure 16). In practice, mould
temperatures in the range 30-50°C have been found
to offer the best compromise between the effects of
'frozen-in strain' and notch-sensitivity. Figure 23 shows
the variation of retraction with mould temperature for
a constant cylinder temperature.
Melt viscosity (and hence melt temperature) is the
most important factor determining 'frozen-in strain'.
As highlighted in Appendix 1 the presence of 'frozen-in
strain' is associated with orientation of the polyethylene
molecules as they are injected into the mould cavity. At
high temperatures the viscosity of the polyethylene is low
and the mould is filled rapidly: only the layer of material
immediately adjacent to the mould surface has frozen
before the mould is filled so that during cooling the
maximum relaxation of orientation can take place.
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19
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5 INJECTION MOULDING
I
RETRACTION - %
7
5
50
60
ao
60
Figure 24 shows mouldings made from the same type of
polyethylene at the same cylinder temperature, but using
different injection dwell times and pressures. The samples
moulded at high pressure with a long dwell time appear
indistinguishable from those moulded under more
favourable conditions. But when the mouldings are cut
open, it can be seen that excessively high pressures and
long dwell times can result in a thickening of the base near
the sprue, which in extreme cases, can result in thickness
increases of approximately 30%. When the mouldings were
then subjected to an accelerated service test in an active
environment, the effects of too much packing constituted
a very serious cracking hazard.
MOULD TEMPERATURE - °C
Mould Filling Time
Figure 23: Variation of Retraction with Mould
Temperature (Cylinder Temperature is Constant)
Because of the importance of correct mould temperature
and the growing tendency to reduce cycle times it is
essential, as already remarked, that in the initial designing
of the mould, provisions should be made for efficient
cooling; unfortunately this is a feature which is all too
often overlooked with consequent difficulties in
subsequent operation.
Injection Variables
The injection variables will be considered under two
headings: injection pressure and dwell time; and mould
filling time.
Injection Pressure and Dwell Time
To produce good mouldings, both quickly and economically,
the injection pressure should be kept to a minimum and
the dwell time made as short as possible. Increasing the
packing of an additional volume of polyethylene into the
mould during the dwell time to compensate for the
shrinkage of the polyethylene due to crystallisation is also
important. The degree of packing should be kept to a
minimum because the excess polyethylene is forced into
the mould cavity when the melt has almost solidified and
therefore orientation introduced at this stage relaxes
slowly. This can result in a highly strained region being
formed near the sprue/gate. The strain may be sufficient
to initiate stress cracking and therefore the dwell time and
injection pressure must be kept to a minimum.
20
On some machines the injection speed can be varied
virtually independently of the injection pressure by
means of a flow control valve. In long, thin flow paths the
polyethylene will cool rapidly and this section will contain
a fairly high degree of strain. In addition, thin-walled
mouldings require higher pressures to fill the mould and,
therefore, packing may occur before the extremities of
the flow path have been reached. The remedy is to use a
higher melt temperature and as fast an injection speed as
possible. On the other hand, for thick-sectioned mouldings
it is often an advantage to reduce the speed of injection
so as to avoid jetting' and turbulence which will lead to
mouldings with a poor surface finish.
Summary
The moulding conditions necessary to produce good
mouldings with the best appearance and the lowest
amount of 'frozen-in strain' are:
• A melt temperature just high enough to give a glossy
surface to the moulding
• A mould temperature of about 30-50°C
• The minimum injection pressure and dwell time
Qenos Technical Guides
FOI Document #12
INJECTION MOULDING 5
normal injection dwell time
normal pressure
excessive injection dwell time
excessive pressure: note thickening
(a) before test
(b) After accelerated cracking test
Figure 24: Effect of Injection Pressure and Dwell Time on Polyethylene Mouldings
MOULDING FAULTS
Faults in polyethylene mouldings may be divided into two
classes: those that are obvious from visual inspection
and those arising from the presence of 'frozen-in strain' these can be detected only by testing. Appendix 2 lists the
obvious faults that can occur, with their possible causes
and remedies. Faults arising from 'frozen-in strain' have
already been dealt with earlier.
In using Appendix 2 it should be noted that because the
machine variables are interdependent a remedy that
involves the adjustment of any one machine variable may
Qenos Technical Guides
also necessitate adjustment of the others. Alteration of
the melt temperature should be gradual, in steps of 10°C,
and a full cylinder of material should be injected before
the results of any 10°C step are assessed. Alteration of
the cycle time (which affects the length of time the material
is in the cylinder and hence the melt temperature) should
also be carried out gradually. Enough time should be
allowed between successive adjustments to ensure that
steady conditions at any one setting are obtained before
the effect of that setting on the quality of the mouldings
is determined.
21
FOI Document #12
5 INJECTION MOULDING
MOULD RELEASE AGENTS
Embossing
If the correct moulding conditions have been chosen,
polyethylene mouldings are unlikely to stick in the mould.
If they do, and the fault cannot be corrected by adjusting
the moulding conditions, mould lubricants such as
stearates or fatty amides may be used. Silicone oils and
greases may cause environmental stress cracking in
polyethylene mouldings and therefore before they are
used as mould release agents they should be tested with
the moulding to see if they are suitable. If any doubt exists
as to their suitability they should not be used.
A relief pattern on mouldings is easily achieved by cutting
the pattern in the mould. Conversely, a relief pattern on
the mould produces a corresponding recessed pattern
in the moulding. The embossed design can subsequently
be decorated by printing or by painting. A wide range of
textures and finishes can be obtained by this method.
DECORATING POLYETHYLENE MOULDINGS
There are several ways in which polyethylene mouldings
can be decorated. These fall into two classes: those
applied directly to the polyethylene surface; and those
which require some form of pre-treatment of the surface.
The following sections briefly deal with the various methods
of pre-treatment, decoration and also with tests for the
effectiveness of these processes.
Decorating Untreated Polyethylene
The following methods are commonly used:
• Hot stamping
• Labelling
Decorating Treated Polyethylene
Pre-treatment
Because polyethylene is non-polar and cannot be dissolved
in any known solvent at room temperature it is not possible
to directly apply conventional inks, paints and lacquers.
There are, however, several ways in which polyethylene can
be made polar. These are:
• Chlorination
• Chemical oxidation
• Flaming
• Electronic methods
Of these, chlorination is of little commercial importance,
and electronic methods are usually restricted to thin films.
Flaming is a versatile process which can handle any
surfaces which do not contain deep or intricately shaped
recesses. Chemical methods are not used so frequently, but
they are the most satisfactory for parts of complex design.
• Embossing
Flame Treatment
Hot Stamping
Basically, this method consists of pressing on to the
polyethylene a tape which is coated with pigment. Heat
and pressure are applied via a male die and the pigment
is released from the tape and fused into the polyethylene.
Stamping should preferably be carried out while the
moulding is still warm after being ejected from the die.
Because it is recessed, the coating obtained by hot
stamping has a good degree of scratch resistance. Other
advantages of this process are the absence of solvents
and negating the need for drying facilities.
Labelling
Labelling is an inexpensive way of achieving a very wide
range of effects. The choice of adhesive will depend on
whether the label is required to be permanently fixed or
easily removed.
Flaming a polyethylene moulding results in slight oxidation
of the surface. This provides a polar surface which is
required for good adhesion. The flame should be oxygen
rich, of constant length and should impinge on the surface
long enough to result in dulling of the surface. The exact
technique will vary according to the shape of the part being
treated. The essential point is that all parts of the surface
should be uniformly treated.
Chemical Treatment
Chemical methods of pre-treatment involving acid etching
are costly and often difficult to operate, but they are
used for complicated parts and for parts to be vacuum
metallised. Basically the procedure is simple:
• The moulding is immersed for 30 sec to 2 min in an
acidified dichromate solution (a typical solution is
100 cm3 of concentrated sulphuric acid, 50 cm3 water
and 15 g of potassium dichromate),
• Removed from the bath, washed thoroughly and dried.
22
Qenos Technical Guides
FOI Document #12
INJECTION MOULDING 5
The big disadvantage of this method is the need to handle
acid solutions; the main advantage is that every part of the
surface, provided it is clean, is treated in the same way.
Tests for Pre-treatment
It is obviously desirable to be able to test the effectiveness
of any pre-treatment to ensure good adhesion of the
finished coating. Several tests can be used, of which those
based on 'wettability' of the surface are popular because
of their simplicity.
Peel Test
r-
This test involves the use of a solvent-free, pressure
sensitive tape. Such a tape has little affinity for an
untreated polyethylene surface and is removed fairly easily,
whereas it will bond strongly to a treated surface. A
suitable tape is No. 850 supplied by Minnesota Mining and
Manufacturing Co. Ltd. (3M). The tape is rolled on to the
moulding by means of a rubber roller and is then peeled off
under standard conditions using a tensometer. By noting
the 'peel strength' recorded, a quantitative indication of the
treatment level can be obtained. Since decorative coatings
vary in their adhesion to polyethylene surfaces, there is no
basic correlation between peel strength and adhesion.
However, it has been found that treatments giving peel
strengths greater than about 120 g/cm will result in
satisfactory adhesion of most coatings.
Screen printing has the great advantage of low capital
cost, particularly when the operation is done manually.
Fully automatic units are available. The main disadvantage
of silk-screening is that no more than one colour can
be applied at one pass. If additional colours need to be
applied, then the moulding must be dried before the next
colour is applied.
Vacuum Metallising
In vacuum metallising a thin continuous layer of metal
is deposited onto a prepared surface by vaporising the
metal under high vacuum and condensing it on the
surface. In practice, a lacquer is applied to the pre-treated
polyethylene as a base coat. This serves to smooth out any
imperfections and also acts as a key for the metallic film.
The metallic film (usually of aluminium) is deposited, and
a top coat of protective lacquer is applied. Low density
polyethylene articles are successfully finished in this way.
Although the flexibility of the material is a disadvantage.
Tests for Finished Coatings
Two simple but effective tests are the Scratch test and the
Scotch Tape test.
Scratch Test
A good idea of the adhesion of a coating can be obtained
by scratching it with a finger nail or a knife to see if it flakes.
Decorating Methods for Treated Surfaces
Scotch Tape Test
Two methods that can be used are:
In this test a length of pressure-sensitive tape such as
Scotch Tape supplied by 3M is stuck on to the polyethylene
moulding and then pulled off, slowly at first and then more
quickly. The level of adhesion of the coating can be judged
qualitatively by the degree, if any, to which the coating is
removed.
• Silk-screen printing
• Vacuum metalising
Silk-screening
This is essentially a stencilling process in which the stencil
takes the form of a silk, nylon or metal screen which has
been made porous, by a photographic process, over areas
corresponding to the design to be printed. The screen
is held taut in a wooden frame which also serves as a
reservoir for the ink. In use, the screen, with ink on its
upper surface, is placed in contact with the article and a
rubber 'squeegee' is drawn over the screen, thus forcing
ink through the porous area on to the article.
Qenos Technical Guides
23
FOI Document #12
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5 INJECTION MOULDING
APPENDIX 1— FROZEN-IN STRAIN
r\
It is believed that 'frozen-in strain' develops in the following
way. As the polyethylene melt is injected into the mould
cavity, it is subjected to high shear forces which produce
a certain degree of uncoiling of the molecular chains and
causes them to be oriented in the direction of flow. The
nearer the melt is to the mould surface, the greater will be
the shear stress and the greater the orientation. Because
the material nearest to the mould surface cools more
rapidly than the material in the interior, this orientation
is unable to relax and becomes frozen into position. Thus
a highly oriented layer is formed, the thickness of which
depends on the temperatures of the melt and of the mould
surface. On the other hand, the material on the inside is
insulated from the cool mould by a layer of polyethylene
and consequently it remains molten until near the end of
the moulding cycle. Not only is this material less oriented
during mould filling, but most of the orientation that does
occur can relax during the cooling stage. Therefore an
injection moulded section has a composite structure
consisting of a skin which is highly strained and inner
layers containing a much lower degree of molecular
orientation. Figure 25 is a greatly magnified picture of
a section cut through an injection moulding which shows
clearly the different layers that are formed. In service, the
oriented chains will tend to revert to their normal, coiled
configuration and this tendency is reflected in a reduction
in the dimensions of a specimen parallel to the direction
of flow and an increase in the dimensions at right angles
to the flow. If these dimensional changes are resisted by
the shape of the moulding, mechanical forces arise which
can produce internal stresses large enough to cause
cracking in the presence of an active environment.
If a highly strained surface comes into contact with an
active environment such as synthetic detergents or fat,
a small crack may develop which is likely to propagate
rapidly, especially at elevated temperatures. Depending
on the particular type of polyethylene, either cracks may
develop throughout the whole section or failure may be
restricted to surface peeling.
Figure 25: A Section from a Polyethylene Moulding,
Showing the Layered Structure
At elevated temperatures the tendency for the oriented
molecules to revert to their normal configuration is
increased and some measure of the degree of orientation
can be obtained by cutting specimens from a moulding and
measuring the percentage retraction which takes place in
the direction of flow when the specimens are heated. A
large retraction indicates a high level of 'frozen-in strain'.
24
Qenos Technical Guides
FOI Document #12
702_,
INJECTION MOULDING 5
APPENDIX 2- INJECTION MOULDING TROUBLESHOOTING GUIDE
Problem/Issue
Cause(s)
Potential Solution(s)/Action(s)
Brittle mouldings
Sharp corners, notches
Increase radii
Inadequate thickness
Increase thickness of moulding
Insufficient venting
Increase venting
Burn marks.
Carbonised
material at end
of flow path
Injection speed too high
Reduce injection speed
Melt temperature too high
Reduce barrel and nozzle temperature settings
Delamination
Incompatible masterbatch
Ensure PE based masterbatch is used
Contaminant
Check feed for contamination
Material freezing prematurely
Increase temperature settings. Increase gate size
Poor design, insufficient draft angles
Increase draft angles, incorporate "slip"additive
Over packing
Reduce injection speed and or second stage time/
pressure, use higher flow PE grade
Excessive second stage
Reduce second stage pressure and/or time
Variation in mould cooling
Increase cooling channels in difficult to cool areas
Sink marks
Increase second stage pressure and or time
Gate freezing off too quickly
Increase gate size
PE melt flow index too high
Change to a low flow grade of PE
Excessive injection speed
Reduce injection speed
Back pressure too low
Increase back pressure
Masterbatch not compatible
Ensure PE based masterbatch is used
Temperature too low
Increase temperature settings
Demoulding
difficulties
Poor colour
homogenisation
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FOI Document #12
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5 INJECTION MOULDING
Problem/Issue
Cause(s)
Potential Solution(s)/Action(s)
Short shots.
Incompletely
filled mouldings
PE melt flow index too low
Change to higher melt flow index grade
Melt temperature too low
Increase melt temperature.
Inadequate vent size
Increase venting
Inadequate thickness
Increase thickness
Insufficient injection speed
Increase injection speed
Insufficient gating
Increase gate size or number
Melt temperature too low
Increase temperature settings
Flow of polymer too low
Use higher melt flow grade
Injection speed too low
Increase injection speed
Gate(s) too far from weld line
Move gate or increase number of gates
Weak weld lines
Disclaimer
The proposed solutions in this guide are based on conditions that are typically encountered in the manufacture of products from polyethylene.
Other variables or constraints may impact the ability of the user to apply these solutions. Qenos also refers the user to the disclaimer at the beginning
of this document.
26
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FOI Document #12
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INJECTION MOULDING 5
BIBLIOGRAPHY/FURTHER READING
1. Rosato, D. V.; Rosato, D. V.; Rosato, M. G.; Injection Moulding Handbook (3rd Ed.), Kluwer Academic Publishers, 2000.
2. Johannaber, F.; Injection Moulding Machines - A User's Guide, (4th Ed.), Hanser Verlag, 2008.
3. Bryce, D. M.; Plastic Injection Moulding - Manufacturing process fundamentals, Society of Manufacturing
Engineers, 1996.
4. Osswald, T. A.; Turnig, L.; Gramann, P. J.; Injection Moulding Handbook, Hanser Verlag, 2008.
5. Potsch, G.; Michaeli, W.; Injection Moulding An Introduction, (2nd Ed.), Hanser Verlag, 2008.
6. Rueda, D. R.; Balta Calleja, F. J.; Bayer, R. K.; J. Mat Sci, 16, 3371, 1981.
Influence of processing conditions on the structure and surface microhardness of injection-moulded polyethylene.
Issued January 2014.
Qenos Technical Guides
27
FOI Document #12
aer:1(4,
Qenos Pty. Ltd.
ABN: 62 054 196 771
Cnr Kororoit Creek Road & Maidstone Street,
Altona Victoria 3018, Australia
T: 1800 063 573 F: 1800 638 981
genos.com
Afk
AuA$ MA
s,
FOI Document #13
UNCLASSIFIED
s47F
From:
Sent:
To:
Cc:
Subject:
Attachments:
s47F
@qenos.com
Friday, 5 September 2014 11:47 AM
TARCON
s47F
@qenos.com
Objection Gazette no TC 14/33, TO 1425826
HD3690-CON item cost.xlsx; Polyethylene at a Glance 6th Edition.pdf; Book 5 injection
Moulding.pdf; Qenos invoices HD3690 CON 2014.pdf; TO 1425826 objection Sep 14
signed.pdf
Dear National Manager, Tariff Branch
Please find attached Qenos' objection to Gazette no TO 14/33, TO 1425826 and supporting material.
s47F
s47F
Qenos Pty Ltd
P: s47F
I M: s47F
E: s47F
qenos.com I W: www.cienos.com
Qenos
1
UNCLASSIFIED
12)1
FOI Document #14
22,
tty
••••••
If this form was completed by a business with fewer than 20 employees,
please provide an estimate of the time taken to complete this form.
TIME
SAVER
1Hours
iMinutes
SUBMISSION OBJECTING TO THE MAKING OF A
TARIFF CONCESSION ORDER (TCO)
THIS FORM MUST BE COMPLETED BY A LOCAL MANUFACTURER WHO WISHES TOOBJECT TO THE GRANTING OF A TCO.
THE INFORMATION PROVIDED ON THIS PAGE WILL BE FORWARDED TO THE APPLICANT FOR THE TCO.
THE FORM SHOULD BE READ CAREFULLY BEFORE BEING COMPLETED.
DETAILS OF THE TCO APPLICATION TO WHICH THIS SUBMISSION REFERS
DATE
GAZETTE No TO 14/33
Gazetted description of goods.
TC Reference Number
27 August2014
TC
1425926
RESINS, unpigmented polypropylene heterophasic copolymer,
proplyene based with comonomer ethylene, in pelletised form,
having ALL of the following: (refer TO 1425826)
Stated use: For the manufacture of this walled containers for food packaging
using high speed injection moulding
LOCAL MANUFACTURER DETAILS
Name
Qenos
Business Address
471-513 Kororoit Creek Road, Altona VIC 3018
Postal Address (if the same as business address write as above")
Private Mail Bag 3, Altona VIC 3018
Australian Business Number (A.B.N.)
Reference
62 054 196 771
Company Contact
s47F
Phone Number
s47F
Facsimile Number
s47F
E-mail Address
s47F
@genos.com
DETAILS OF THE SUBSTITUTABLE GOODS PRODUCED IN AUSTRALIA
Describe the focally produced substitutable goods the subject of the objection,
"Substitutable goods" are defined in the Customs Act 1901 as "goods produced in Australia that arept-ft, or are capable of being put, to a use That
corresponds with a use (including a design use) to which the goods the subject of the application aof the TCO can be pur.
High density polyethylene (HDPE) injection moulding resin.
2
State the use(s) to which the substitutable goods are put or are capable of being put.
Housewares, thin walled containers and closures.
B444 (JUN 2001)
FOI Document #14
I L!
3
Attach technical, illustrative descriptive material and/or a sample to enable a full and accurate identification and
understanding of the substitutable goods.
4
Are you aware of any other local manufacturers producing substitutable goods?
5
If yes to question 4, please provide details of any goods produced in Australia which are substitutable for the goods for
which a TCO is being sought, and the names and addresses of the manufacturers of those goods.
6
PRODUCTION OF GOODS IN AUSTRALIA
DYES
Ei NO
Goods other than unmanufactured raw products will be taken to have been produced in Australia if:
(a)
the goods are wholly or partly manufactured in Australia; and
(b)
not less than 1/4 of the factory or works costs of the goods is represented by the sum of:
(I) the value of Australian labour; and
(ii) the value of Australian materials; and
(iii) the factory overhead expenses incurred in Australia in respect of the goods.
Goods are to be taken to have been partly manufactured in Australia if at least one substantial process in the manufacture of the goods
was carried out in Australia.
Without limiting the meaning of the expression "substantial process in the manufacture of the goods", any of the following operations or
any combination of those operations DOES NOT constitute such a process:
(a)
operations to preserve goods during transportation or storage;
(b)
operations to improve the packing or labelling or marketable quality of goods;
(c)
operations to prepare goods for shipment;
(d)
simple assembly operations;
(e)
operations to mix goods where the resulting product does not have different properties from those of the goods that have been mixed.
A
Are the goods wholly or partly manufactured in Australia?
•
•
Does the total value of Australian labour, Australian materials and factory overhead
expenses incurred in Australia represent at least 25% of the factory or works costs?
0 YES 0 NO
YES D NO
Specify each of the following costs per unit for the substitutable goods:
• Australian labour
s47
s
4
• Australian materials
s47G
s
7
4
• Australian factory overhead expenses
G
s
s47G
7
4
• Imported content
G
s
s47G
7
4
G
TOTAL
s47G
7
Specify the date or period to which the costs relate. 12 months ending
G 31 Aug 2014
s47G
Attach a copy of the working papers that were used to prepare the above costing information. Those working papers should be
supported by (at least two) extracts from the accounting records of the business.
•
Is at least one substantial process in the manufacture of the goods carried out in Australia? 0 YES 0 NO
If yes, please specify at least one major process involved:
Conversion of Ethane gas supplied from Bass Strait into ethylene using a steam cracking process and then
polymerised into polyethylene at Qenos's Altona Victoria polymer manufacturing facility.
FOI Document #14
/20
7
PRODUCTION OF GOODS IN THE ORDINARYCOURSEOF BUSINESS
(Answer 7.1 or 7.2)
7.1
SUBSTITUTABLE GOODS OTHER THAN MADE-TO-ORDER CAPITAL EQUIPMENT
Substitutable goods (other than made-to-order capital equipment) are taken to be produced in Australia in the ordinary course of business if:
(a)
they have been produced in Australia in the 2 years before the application was lodged; or
(b)
they have been produced, and are held in stock, in Australia; or
(c)
they are produced in Australia on an intermittent basis and have been so produced in the 5 years before the application was
lodged;
and a producer in Australia is prepared to accept an order to supply such goods.
A
Have the goods been produced in Australia in the last 2 years?
EYES D NO
•
Have the goods been produced and are they held in stock in Australia?
E
If the goods are intermittently produced in Australia, have they been so produced
11 YES
El NO
El YES
D NO
•
YES El NO
in the last 5 years?
•
Are you prepared to accept an order for the goods?
7.2
SUBSTITUTABLE GOODS BEING MADE-TO-ORDER CAPITAL EQUIPMENT
"Made-to-order capital equipment" means a particular item of capital equipment that is made in Australia on a one-off basis to meet
a specific order rather than being the subject of regular or intermittent production and that is not produced in quantities indicative of
a production run. Capital equipment means goods which, if imported, would be goods to which Chapters 84, 85, 86, 87, 89 or 90
of Schedule 3 to the Customs Tariff Act 1995 would apply.
Goods that are made-to-order capital equipment are taken to be produced in Australia in the ordinary course of business if:
(a)
a producer in Australia:
(1)
has made goods requiring the same labour skills, technology and design expertise as the substitutable goods in the 2 years
(ii)
could produce the goods with existing facilities; and
before the application; and
(b)
the producer in Australia is prepared to accept an order to supply The substitutable goods.
Have goods requiring the same labour skills, technology and design expertise as the
goods the subject of the application been made in Australia in the last 2 years?
D
YES
ENO
If yes, describe the goods made during this period:
Can the goods be produced with existing facilities?
D YES El NO
•
Are you prepared to accept an order for the goods?
I: YES
8
What was the first date on which you were prepared to accept an order?
Are the goods still in production?
If the answer is no, when did production cease?
If production has ceased and goods are held in stock, please estimate the date by
which stock is expected to be sold, based on past sales information and attrition
rate of the local goods.
1
/1
El NO
/1980
[3 YES DNO
FOI Document #14
/1?
9
Provide any additional information in support of your objection.
Cost analysis based on the bill of materials (provided) for Qenos grade HD3690 packaged in 20 tonne
bulk containers for local delivery. Sample customer invoices have also been provided.
This product has been in production for several decades - the answer to question 8 on the first date
on which Qenos was prepared to accept an order is indicative only.
A copy of Qenost product guide "Polyethylene at a glance" and Qenos' technical guide on
injection moulding have been provided in response to question 3.
NOTES
(a) Section 269K and 269M ofthe Customs Act 1901 require that a submission opposing the making of a TCO be in writing,
be in an "approved form", contain such information as the form requires, and be signed in the manner indicated in the
form. This is the approved form for the purposes of those sections.
(b) A submission will be date stamped on the day it is first received in Canberra by an officer of Customs. The submission
is taken to have been lodged on that day.
(c) For the submission to be taken into account, it must be lodged with Customs:
• no later than 50 days after the gazettal day for an application for a TOO;
• no later than 14 days after the gazettal day for an amended application for a TCO; or,
• where the Chief Executive Officer has invited a submission, within the period specified in the invitation.
(d) Every question on the form must be answered.
(e) Where the form provides insufficient space to answer a question, an answer may be provided in an attachment. The
attachment should clearly identify the question to which it relates.
(f) Unless otherwise specified, all information provided should be based on the situation as at the date of lodgement of the
TCO application.
(g) Customs may require an objector to substantiate, with documentary evidence, information provided in relation to the
objection.
(h) Further information on the Tariff Concession System is available in PartXVA of the Customs Act 1901, in theforeword
to the Schedule of Concessional Instruments, in the administrative guidelines in Volume 13 of the Australian Customs
Service Manual, in Australian Customs Notice No. 98/19, on the internet at www.customs.gov.au, by e-mailing
[email protected] or by phoning the Customs Information Centre on 1300 363263.
I agree, in submitting this form by electronic means (including facsimile) that, for the purposes of Sub-Section 14(3) of the
Electronic Transactions Act, this submission will be taken to have been lodged when it is first received by an officer of Customs,
or if by e-mail, when it is first accessed by an officer of Customs, as specified in Sub-Section 269F(4) of the Customs Act.
Full Name
Position Held
s47F
s47F
Signature
s47F
Date
5 September 2014
NOTE:
SECTION 234 OF THE CUSTOMS ACT 1901 PROVIDES THAT IT IS AN OFFENCE TO MAKE A STATEMENT TO AN
OFFICER THAT IS FALSE OR MISLEADING (NA MATERIAL PARTICULAR.
WHEN THIS FORM HAS BEEN COMPLETED LODGE IT WITH CUSTOMS BY:
• posting it by prepaid post to the
National Manager, Tariff Branch
Australian Customs Service
Customs House
5 Constitution Avenue
CANBERRA ACT 2601
or
delivering it to the ACT Regional Office located at
Customs House, Canberra
Or
sending it by facsimile to (02) 6275 6376
Or
e-mailing it to tarcongoustoms.gov.au.
FOI Document #17
//)--
Oenos
A giu estar comparw
FOI Document #17
AlkadyneTM PE100 Pipe Extrusion Grades
Melt Index
Grade
ig110 mind 190 C.
5.00kg)
Density'
Applications
(91cm )
HDF193B
0.3
0.961(1)
High Density black PE100 type resin certified to AS/NZS 4131, for use in pressure pipes and fittings. Excellent low
sag properties and throughput, suitable for the majority of PE100 pipe dimensions.
HDF145B
0.2
0.9610)
High Density black PE100 type resin certified to AS/NZS 4131, for use in pressure pipes and fittings Exceptional
low sag properties and throughput, suitable for the most challenging pipe dimensions.
HDF193N
0.3
0.9520)
High Density natural resin for extrusion into a full range of non standard pipe products and as a base for PE100
type striping and jacket compounds.
Notes: 0)ASTM D1505/D2839
AlkadyneTm PE Pipe Extrusion Grades
Melt Index*
Grade
(9)10 min @ 190°C,
5.00kg)
Density'
Applications
(91cm'i
MD0898
0.7
0.9520)
Medium Density black PE8OB type resin certified to AS/NZS 4131 for use in pressure pipes and fittings.
MD0592
0.6
0.9420)
Medium Density natural resin for extrusion into a full range of non standard pipe products and as a base for PE80
type striping and jacket compounds.
GM7655
0.6
0.9540)
High Density natural high molecular weight resin for extrusion into a full range of non standard pipe products.
MDF169
1.0
0.9430)
Medium Density natural high molecular weight resin for extrusion into a full range of non standard pipe products.
LL0228
1.7(2)
0.9230)
Linear Low Density resin for use in pipe extrusion applications.
Notes: olASTM D1505/D2839 (2) [email protected]°C, 2.16kg
AlkadyneTM PE Wire and Cable Grades
Grade
Melt Index
19/10 min @ 190°C,
2 16kg)
Density#
(g/cm
Applications
MD0592
0.12
0.942(1)
Designed for extrusion into a full range of wire and cable products where natural Medium Density resins are required.
MD0898-1
0.12
0.9530)
Designed as general purpose jacketing compound for buried wires and cables where abrasion and cut through
resistance is required.
Notes: 0)ASTM D1505/D2839
Alkatane HDPE Tape and Monofilament Grades
Grade
Melt Index.
(9/10 min @ 1901C,
2.16kg)
GF7740F2
0.4
Density"
(91cm')
0.950(1)
Applications
Extrusion applications including stretched tape, monofilament, tarpaulins, and over-pouches for medicinal products.
Notes: (1) ASTM D1505/D2839
Alkatuff® LLDPE Rotational Moulding Grades
Melt Index
Grade
(9,10 min @ 190C,
2.16kg)
Density"
(g crn )
Application
LL711UV
3
0.938
Applications requiring excellent ESCR, chemical resistance, stiffness, toughness and UV protection, such as
water and chemical tanks, septic systems and kayaks.
LL705UV
5
0.935
Applications requiring high ESCR, chemical resistance, toughness, stiffness and high level UV stabiliser, such as
leisure craft, playground equipment and agricultural tanks.
LL755
5
0.935
Applications requiring high ESCR, chemical resistance, toughness and stiffness. Incorporation of suitable UV
stabilisation is required for outdoor applications.
10
0.930
High speed intricate applications requiring good ESCR, chemical resistance"), toughness and UV protection,
such as consumer goods and playground equipment.
LL710UV
Notes: (11 The level of chemical resistance is a function of product design and environmental conditions. Contact Genoa for further information.
Melt Index according to ASTM 01238 unless otherwise annotated
*
gDensity according to ASTM D1505 unless otherwise annotated
FOI Document #17
/1.3
Additives
Alkathene® LDPE Film Grades
Grade
•
Melt Index
(9/10 mm © 1901C,
2.16kg)
Density
(g/cm')
Applications
is)
co
co
>,
in
=
-..
.
"t
a
Applications
7°-
E5
>-.
ai E
I CO
-8
=
Ct.
'1,
MI
a• .=
,'7, E3
C)an
XDS34
0.30
0.922
Heavy chly sacks, pallet wrap and industrial applications requiring heavy gauge
film. Add. ve free.
LDF433
0.45
0.925
Heavy duty sacks, pallet wrap and industrial applications requiring medium to
heavy gauge film with increased stiffness.
v
v
LDD201
0.45
0.922
General purpose medium to heavy gauge film for heavy duty bags and shrink
film and for use as a blend component.
v
Y
LDD203
0.45
0.922
General purpose medium to heavy gauge film for heavy duty bags and shrink
film requiring antiblock, and for use as a blend component.
,/
Y
v
LDD204
0.45
0.922
General purpose medium to heavy gauge film for heavy duty bags and shrink
film where a medium level of slip is required.
,/
to
y
,/
LD0205
0.45
0.922
General purpose medium to heavy gauge film for heavy duty bags, frozen food
and produce bags where a high level of slip is required or for use as a blend
component.
Y
H
Y
v
Y
LDH210
1.0
0.922
Bundle shrink and other medium gauge film applications such as produce bags,
carry bags and for blending into other film grades.
v
Y
Y
LDH215
1.0
0.922
General purpose medium gauge film for produce bags and carry bags, frozen
food where a high level of slip is required or for use as a blend component.
Y
Y
XJF143
2.5
0.921
Additive free, general purpose low gauge film for overwrap and other
applications and for use as a blend component.
LDJ226
2.5
0.922
Bundle shrink, low gauge shrink film and general purpose applications where a
medium level of slip and antistatic are required.
,/
to, ,
LD0220MS
2.5
0.922
High quality low gauge film for lamination and overwrap applications where a
medium level of slip is required.
st
ki
LDJ225
2.5
0.922
High quality, low gauge film primarily intended for bread bags and overwrap but
also general purpose applications where a very high level of slip is required.
,/
VH
XLF197
5.5
0.920
High quality, very thin gauge and high clarity film primarily intended for food and
packaging wrap and for drycleaning film. Additive free.
/
cL. g
C,)
a,
o
v
N('
H
a5
2
6:
0
a, NJ
= S3
b
?>3
Y
v
,/
v
v
v
Y
Y
Y
0.8
0.922
Heavy duty sacks, agricultural films,lamination and form, fill and seal
packaging where enhanced toughness and sealing characteristics are
desired.
LL501
1.0
0.925
General purpose industrial, agricultural and heavy duty films and as a
blend component to improve film handling in converting and packaging
operations.
LL601
1.0
0.925
General purpose industrial, agricultural and heavy duty films and as a
blend component to improve film handling in converting and packaging
operations.
LL425
2.5
0.918
High quality cast film for applications that require toughness,
high clarity and processability.
V
V
V
V
.
Applications
Notes: 0)VII= Very High Slip, H = High Slip, M = Medium Slip
*Melt Index according to ASTM D1238 unless otherwise annotated
#Density according to ASTM 01505 unless otherwise annotated
=
...
C.
rc
V
V
V
V
.7
V
Garbage Bags
LL438
GeneralPurpose
Density"
:Agricultura lFilm
Melt Index
410 min 0. 190 C.
2.1641
Heavy Duty Bags 1
Grade
1
—
['cat'
Processing Aid
Adcitive
Alkatuff® LLDPE Film Grades
7
c'
n
Notes: ii Based on antistat additive Si VH = Very High Slip, H = High Slip, M = Medium Slip
V
H
V
V
V
FOI Document #17
Density#
(glcm')
Co
Applications
fit
0.
111•111
CO
ML1810PN
1.0
0.918
Heavy duty bags, industrial and agricultural films, and
form, fill and seal applications and ice bags where
outstanding toughness, sealing and hot tack properties
are desirable or for downgauging of existing film
structures.
ML1810PS
1.0
0.918
Heavy duty bags,industrial and form, fill and seal
applications and ice bags Mere outstanding toughness,
sealing, hot tack properties and high slip are desirable
or for downgauging of existing film structures.
Vt
V
ML2610PN
1.0
0.926
Heavy duty bags, lamination, industrial and form, fill
and seal applications where outstanding stiffness,
toughness, optical and sealing properties are desirable
or for downgauging of existing film structures.
ML1710SC
1.0
0.917
Stretch cling films (with addition of appropriate cling
additive) and other film applications where outstanding
toughness, optical and sealing properties are desirable
or for downgauging of existing film structures.
V V
V
cn
co
CO
‘crsi
General
Purpose
(g/10 min @
190°C, 2.16kg)
Applications
Agricultural Film
Melt Index
Grade
Additives
Heavy Duty Bags
Alkamax® mLLDPE Film Grades
V V V
Vt
V
V
Vt
LI
72
Co
CO
U-
0.
Co
a)
u_
V V ,/ V V V
Vt
Vt
cr)
Cr,
CD
,/
Vt
Vt
V
Vt
,/
Vt
Vt
Vt
V
V
Notes: 11)VH = Very High Slip, H = High Slip, M = Medium Slip
AlkataneTM HDPE Film Grades
Melt Index
Grade
15110 min @
190'C, 2.16kg)
Applications
Density# Applications
(g/cm')
I
I
GM4755F
0.10
0.9550)
Carry bags and liners where high impact, toughness and stiffness are desirable and as a blend component into
LDPE and [LOPE films for heavy duty applications.
HDF895
0.80
0.9600)
Moisture barrier and blend component into LD PE and LLDPE films to enhance stiffness. Blend component in core
layer for high clarity coextruded films.
V V V
V
V
V
Notes: 0)ASTM D1505/D2839
AlkataneTM HOPE Blow Moulding Grades
Grade
Melt Index*
(g/10 min @ 190 C,
2 16kg)
Density'
(g/cml
Applications
HD0840
0.06
0.9530)
Large part blow mouldings, especially blow moulded self-supported drums and tanks (25 - 220 litres).
Exceptional ESCR.
HD1155
0.07
0.953(1)
Large part blow mouldings, including 25 litre to 220 litre tanks and drums. Exceptional ESCR.
GM7655
0.09
0.9540)
Blow moulded containers including household and industrial chemical (HIC). Suitable for larger part mouldings.
Exceptional ESCR.
GF7660
0.30
0.9590)
Household and industrial chemical (H IC) containers, including detergent and pharmaceutical bottles.
Excellent ESCR.
GE4760
0.60
0.9640)
Blow moulded water, dairy and fruit juice bottles.
HD5148
0.83
0.9620)
High speed dairy packaging applications and other thin walled bottles such as milk, cream, fruit juice and cordial.
Notes: 11) ASTM 01505/D2839
Qenos imported polymers and additives
Complementing our Australian manufactured Polyethylene grades, Qenos acts as a local distributor for a wide range of imported polymers and additives including rubbers,
elastomers, adhesives, plastomers, EVA, BOPP Film, EPS, antioxidants and titanium dioxide. For the full Qenos range, please refer to the Qenos website, Customer Service or your
Account Manager.
*Melt
Index according to ASTM 01238 unless otherwise annotated
#Density according to ASTM D1505 unless otherwise annotated
Vt
FOI Document #17
Alkathene® LDPE Extrusion Coating Grades
Melt Index
2.16kg)
Density°
4cm )
XLC177
4.5
0.923
Applications including milkboard and fabric extrusion coating where very good drawdown, low moisture vapour
transmission rates and excellent hot tack are desirable. Additive free.
WNC199
8.0
0.918
Liquids packaging and other sensitive food packaging laminates where excellent heat seal, low extractables, good
melt strength and low odour and taint are desirable. Additive free.
LDN248
7.6
0.922
Liquids packaging and other sensitive food packaging laminates where low extractables and low odour•and taint are
desirable. Additive free.
LD1217
12
0.918
Liquids packaging and other sensitive food packaging laminates where high line speed, low neck-in, low
extractables and low odour and taint are desirable. Additive free.
Grade
410 min ,d 190 C
Applications
Alkathene® LOPE Injection Moulding Grades
Melt Index*
Density°
Grade
19110 min ,id, 190 C,
2.16kg)
XDS34
0.3
0.922
Small part injection moulded caps and closures. Additive free.
WJG117
1.7
0.918
Thick section mouldings, caps and closures, industrial containers where a high level of toughness is desirable.
Additive free.
XJF143
2.5
0.921
Injection moulded caps and closures, and thick-walled sections. Additive free.
LDN248
7.6
0.922
Injection moulded caps and closures. Additive free.
WRM124
22
0.920
High flow resin for reseal lids, housewares and toys where excellent gloss, low warpage and flow to toughness ratio
are desirable. Additive free.
LD6622
70
0.922
High flow resin for lids and other thin wall injection moulding applications. Additive free.
(Wm g
Applications
Alkatuff® LLDPE Injection Moulding Grades
Melt Index'
Grade
LL820
(00 min @190-C.
2.16kg)
20
Density'
(gicrn'i
0.925
Applications
111111111111111
Injection moulding and compounding applications such as housewares and lids.
AlkataneTM HOPE Injection Moulding Grades
Melt Index*
Density#
Grade
(g110 min @ 191PC,
2.1614
HD0390
4
0.955
Stackable crates for transport, storage and bottles and industrial mouldings where very good mechanical properties
are desirable.
HD0397UV
4
0.955
Mouldings requiring long-term weatherability, including mobile garbage bins, crates, and industrial mouldings where
very good mechanical properties are desirable.
HD0490
4.5
0.955
Stackable crates for transport, storage and bottles, and industrial mouldings where very good mechanical properties
are desirable.
HD0499UV
4.5
0.955
Mouldings requiring long-term weatherability, including mobile garbage bins, crates, and industrial mouldings where
very good mechanical properties are desirable.
HD0790
7
0.956
Industrial pails, crates, closures and sealant cartridges where a good balance between flow and impact resistance is
desirable.
HD1090
10
0.956
Industrial pails, crates, closures and sealant cartridges where a good balance between flow and impact resistance is
desirable.
HD1099UV
10
0.956
Mouldings requiring long term weatherability including industrial pails, crates, and tote boxes where a good balance
between flow and impact resistance is desirable.
HD2090
20
0.956
Housewares, thin-walled containers and closures where excellent mould flow and flexibility is required.
HD3690
36
0.956
Housewares, thin-walled mouldings and closures where excellent mould flow and flexibility is required.
(glcmg
*Melt Index according to ASTM D1238 unless otherwise annotated
Applications
#Density according to ASTM D1505 unless otherwise annotated
FOI Document #17
n
Qenos Pty. Ltd.
ABN: 62 054 196 771
Cnr Kororoit Creek Road & Maidstone Street,
Altona Victoria 3018, Australia
1: 1800 063 573 F: 1800 638 981
custornerse[email protected]
clenos.com
IA
OI
ISO 9001
A0571tAIJA14 MADE
Front Cover: Pellet geometry and pellet quality can have a significant effect on material flow and the efficiency of feeding polyethylene into an extruder. Qenos
measures pellet quality using a pellet shape and size distribution analyser, a device that photographs around 10,000 pellets in 4 minutes. digitally analyses
the images and generates a report on pellet quality. Where a drift in the pellet quality is detected, adjustments are made proactively to maintain high product
integrity.
Rear Cover: The standard for UV performance for PE Water Tanks specified in AS/NZS 4766 PE Tanks for the Storage of Chemicals and Water is 8.000 hours of
uninterrupted exposure to an intense and specifically developed UV light source. Qenos exhaustively tests the longterm UV performance of its Rotational Moulding
Resins under conditions of controlled irradiance, chamber temperature and humidity and repeated rain cycles. Alkatuff® 711UV achieves a class leading UV
performance exceeding 20,000 hours against the required standards, ensuring that Alkatuff® 711UV is "Tough in the Sun':
The contents of this document are offered sdely for your consideration and venficahon and should not be construed as a warranty or representation for which Qenos Ply Ltd assumes legal liability, except
to the extent that such liability is imposed by legislation and cannot be excluded. Values quoted are the result of tests on representative samples and the product supplied may not conform in all respects.
Qenos Pty Ltd reserves the nght to make any improvements or amendments to the composition of any grade or product without alteration to the code number. The applications listed are based on the usage
by exisiting Qenos customers. In using Qenos Pty Ltd's products, you must establish for yourself the most suitable formulation, production method and control tests to ensure the uniformity and quality of
your product is in compliance with all laws and your requirements.
Qenos, Alkathene, Alkatuff, Alkamax, Alkadyne and Alkatane are trade marks of Qenos Pty. Ltd.
6th Edition November 2013
Ctenos
A Bluestar Company
FOI Document #18
Oenos
A B'uestar rwr.par,
INJECTION
MOULDING
TECHNICAL GUIDE
Alkathene® Alkatuff® AlkataneTM
FOI Document #18
Front Cover:
Qenos produces injection moulded products for applications
including caps, pails, crates, sealant cartridges, mobile
garbage bins, produce bins, housewares and lids. A full range of
Alkatane HDPE, Alkathene LDPE and Alkatuff LLDPE grades are
available across the Melt Index and density spectrum. In addition,
Qenos distributes a number of speciality polymers suitable for
injection moulding.
Qenos, Alkathene, Alkatuff and Alkatane are trade marks of
Qenos Pty. Ltd.
FOI Document #18
INJECTION
MOULDING
5
FOI Document #18
/0,c
5 INJECTION MOULDING
TABLE OF CONTENTS
INTRODUCTION
6
EFFECT OF TYPE OF POLYETHYLENE ON PROCESSING AND PROPERTIES OF MOULDINGS
6
Classification of Polyethylenes
MEI
(
DENSITY
7
Effect of MEI and Density on Moulding Characteristics
7
MOULD FILLING
8
Surface Finish
9
Summary
11
EFFECT OF MFI AND DENSITY ON THE PROPERTIES OF POLYETHYLENE MOULDINGS
11
Stiffness
11
Impact Properties
11
Environmental Stress Cracking
13
Mechanical Stress Cracking
14
Summary
14
SOME ASPECTS OF DESIGNING MOULDS FOR POLYETHYLENE
14
Shrinkage of Polyethylene Mouldings
14
Distortion of Polyethylene Mouldings
16
Mould Design
16
Choice of Polymer
17
Moulding Conditions
17
Weld Lines
17
Flow Weld Lines
18
CONDITIONS FOR MOULDING POLYETHYLENE
18
Cylinder and Melt Temperatures
18
Appearance of Mouldings
19
Frozen-in Strain
19
Mould Temperature
19
Injection Variables
20
Injection Pressure and Dwell Time
20
Mould Filling Time
20
Summary
20
2
Qenos Technical Guides
FOI Document #18
INJECTION MOULDING 5
MOULDING FAULTS
21
MOULD RELEASE AGENTS
22
DECORATING POLYETHYLENE MOULDINGS
22
Decorating Untreated Polyethylene
22
Hot Stamping
22
Labelling
22
Embossing
22
Decorating Treated Polyethylene
22
Pre-treatment
22
Flame Treatment
22
Chemical Treatment
22
Tests for Pre-treatment
23
Peel Test
23
Decorating Methods for Treated Surfaces
23
Silk-screening
23
Vacuum Metallising
23
Tests for Finished Coatings
23
Scratch Test
23
Scotch Tape Test
23
APPENDIX 1 - FROZEN-IN STRAIN
24
APPENDIX 2 - INJECTION MOULDING TROUBLESHOOTING GUIDE
25
BIBLIOGRAPHY/FURTHER READING
27
Qenos Technical Guides
3
FOI Document #18
FOI Document #18
INJECTION MOULDING 5
INTRODUCTION
The purpose of this document is to provide an
introduction to the processing of polyethylene by
injection moulding. The effects of Melt Flow Index (MFI)
and density on moulding characteristics and on the
properties of the finished moulding are discussed, in
the light of which, recommendations are made as to the
desirable values of these two factors for stressed and
unstressed applications.
Mould design is considered with special reference to
questions of shrinkage and distortion and examples are
given to illustrate these points. The moulding process
itself is discussed in some detail, guidance being given on
all the operations which have to be carried out. Moulding
faults, causes and remedies are also summarised.
Disclaimer
All information contained in this publication and any further information, advice, recommendation or assistance given by Qenos either orally or
in writing in relation to the contents of this publication is given in good faith and is believed by Qenos to be as accurate and up-to-date as possible.
The information is offered solely for your information and is not all-inclusive. The user should conduct its own investigations and satisfy itself as to
whether the information is relevant to the user's requirements. The user should not rely upon the information in any way. The information shall not
be construed as representations of any outcome. Qenos expressly disclaims liability for any loss, damage, or injury (including any loss arising out of
negligence) directly or indirectly suffered or incurred as a result of or related to anyone using or relying on any of the information, except to the extent
Qenos is unable to exclude such liability under any relevant legislation.
Freedom from patent rights must not be assumed.
Qenos Technical
Guides
5
FOI Document #18
5 INJECTION MOULDING
INTRODUCTION
Injection moulding is one of the most widely used
processes for converting thermoplastic raw materials
into finished products. Fundamentally, a solid polymer is
plasticated into a molten mass via thermal and frictional
heating and once a suitable volume of melt has been
produced, the polymer is injected into the mould to form
the finished part (see Figures 1 and 2).
Ejector
Pins
Cavity
Nozzle Cylinder
However, this very ease of processing often leads to the
use of moulding conditions which are not the most suitable
for producing the finished part. Also, because almost all of
the many different types of polyethylene can be moulded
on standard equipment, the polyethylene type that is most
suitable for a particular application is not always chosen.
EFFECT OF TYPE OF POLYETHYLENE ON
PROCESSING AND PROPERTIES OF MOULDINGS
To obtain polyethylene mouldings which will withstand
long and arduous service two important questions must
be answered:
Plastic
Granules
a. Which type of polyethylene should be used?
b. What are the correct moulding conditions?
Mould
Melted
Plastic
crew
otor
Drive
To do this it is necessary to know how the different types
of polyethylene used for injection moulding differ from each
other: first, in the way in which they are processed and
second, in the physical properties of the moulded article.
Classification of Polyethylenes
Figure 1: Schematic
Representation of an Injection
Moulding Machine
The most important variables which characterise a
polyethylene are its Melt Flow Index (MFI) and density.
Melt Flow Index (MFI)
MFI is a measure of melt viscosity at low shear rates and
is defined as the weight in grams of polyethylene extruded
in 10 minutes from a special plastometer under a given
load at 190°C. Thus, a low MFI corresponds to a high melt
viscosity. Figure 3 shows how the MFI is related to the
number average molecular weight of the polymer.
n
Melt
Viscosity
- poises
.0* 0
At
vlowerof mot 0o,
•
00000
1,.1rom,*
MELT VISCOSITY
Figure 2: Finished Moulded Part including Sprue
Injection Point
II Number
avergae
molecular
weight
00
Injection Moulding is fundamentally simple, easy to operate
and is capable of producing a very wide variety of industrial
and domestic articles. Of all thermoplastics, polyethylene
is one of the easiest to injection mould. The resin flows
easily into difficult cavities, its viscosity changes smoothly
as the melt temperature increases and it can be processed
over a wide temperature range without decomposition.
6
0
20
10
30000
200
MELT FLOW INDEX
Figure 3: Relation between MFI (g/10 min) and
Number Average Molecular Weight
Qenos Technical Guides
FOI Document #18
10/
INJECTION MOULDING 5
-1Pr
DENSITY
Density is related to the crystallinity of the polyethylene
and is measured in g/cm3.
Because polyethylene molecules are long and contain
branches, complete crystallisation cannot take place
when polyethylene is cooled from the molten state, and
amorphous regions occur between the crystallites. The
smaller the number of branches, the more crystalline
the polyethylene will be and the higher its density.
Although MFI and density are the most important variables
which characterise a polyethylene, it must be emphasised
that all polyethylenes with the same MFI and density are
not necessarily identical. Each polyethylene producer has
specific manufacturing processes and by varying reactor
conditions it is possible, while maintaining a constant
MFI and density, to alter various features of the polymer
such as the molecular weight distribution and the degree
of long and short chain branching that cause changes
'
FILLING
CYCLE
COOLING
CYCLE
2
ryl>
1 MOLD
s' OPENS
PART
A
EJECTS -T
:Mt
Figure 5: Pictorial Representation of the Injection
Moulding Cycle
in the processing behaviour and the physical properties
of the polymer.
As far as the polyethylene is concerned the output of any
injection moulding machine depends predominantly on
two factors:
Effect of MFI and Density on Moulding
• The time taken for the polyethylene to reach moulding
temperature
Characteristics
The injection moulding process is shown diagrammatically
in Figures 4 and 5. For any given machine and mould,
the MFI and density of the polyethylene will considerably
affect the injection dwell and cooling times in the cycle.
The injection time is not significantly affected and the
mould opening, extraction, and mould closing times are
not affected by the MFI or density of the polymer.
Mould closing
Ram beg ins to
move forward
Injection time
Moulding
extracted
Mould
opening
Polythene
under pressure
Injection
dwell time
C
')
Ram withdraws
Figure 4: Injection Moulding Cycle
Qenos Technical Guides
Cooling
time
• The time taken for the polymer to be cooled sufficiently
in order for the moulding to be removed.
A convenient method of assessing the effect of different
types of polyethylene on output rate is to plot the number
of mouldings which can be made in one hour against the
cylinder temperature used. Although the design of the
mould and the type of machine affect output greatly, for
any given mould on a particular machine an output curve
can be obtained by finding for each cylinder temperature
the fastest possible cycle which gives mouldings
acceptable in all respects except for that of surface gloss,
i.e. the minimum injection dwell time, pressure, and cooling
time have been used. A typical curve for a plunger machine
is shown in Figure 6. It will be noticed that, at first, as
the temperature increases the output also increases.
The reason for this is that at low temperatures a long cycle
is necessary to melt the granules thoroughly, but as the
temperature increases, the melting time becomes shorter
and therefore the cycle is also shortened. A point is soon
reached, however, when the time taken to melt the
granules is no longer the limiting factor. The greater
parameter of importance is then the time taken for the
mouldings to cool to a temperature at which they can be
extracted easily from the mould. Beyond this point, as the
melt temperature increases the cycle time has to be
extended and the output consequently falls.
7
FOI Document #18
5 INJECTION MOULDING
To use injection moulding machines most efficiently, the
cylinder temperature should be chosen so that the output
is at its peak. There are, however, two factors which
frequently prevent this being done, namely, the necessity
to fill the mould, and the desire to obtain mouldings with
a good surface finish. These factors are discussed below.
120
••••,
0
-C
E
0.
100
LIMITED BY RATE
OF COOUNG
40
:a
MITED BY RATE
OF PLASTICISATION
70
/
MOULD FILLING
E
WOO
40
1— 0150
1/0
193
230
210
250
270
290
0
CYLINDER TEMPERATURE — °C
Figure 6: Variation in Output Rate of Mouldings with
Cylinder Temperature
Figure 7 shows the effect of density on output rate for
polyethylenes of the same MFI. It indicates that the higher
the density, the higher the output rate on the cooling side
of the curve at any given cylinder temperature. The reason
for this is that mouldings of higher density can be extracted
from the mould at higher temperatures because they are
more rigid at these temperatures than are mouldings of
lower density. The higher density materials, however,
require higher cylinder temperatures to produce adequate
melting of the granules, particularly if the amount of
material being handled is near the plasticising capacity of
the machine, and the use of such temperatures may slow
down the output rate.
In practice, there are some moulds for which it is not
possible to draw an output curve over the whole range
of cylinder temperatures because the mould cannot be
filled at the lower temperatures. Therefore, the moulding
temperature which has to be used is the lowest
temperature at which the mould can be filled, and this
may restrict the output. In order to attain as close to the
maximum theoretical output, good mould filling properties
are obviously desirable in a polyethylene.
The spiral flow test was devised to assess the mould
filling properties of materials. It involves the measurement
of the length of spiral obtained when moulding under
standard conditions using the special mould shown
in Figure 8. In order to compare different types of
polyethylene the cylinder temperature, mould temperature,
cycle time, injection speed and pressure are all held
constant, and under these conditions the length of spiral
obtained gives a good comparative evaluation of the mould
filling properties of the polyethylenes being used.
550
0
CONSTANT MELT FLOW
250 C.
INDEX
01
20
220 C.
C
40
Figure 8: Spiral Flow Mould
a.
0
002
93
094
095
096
DENSITY - G.IC.C.
Figure 9 shows that the main factor which influences ease
of mould filling is MFI. Although density undoubtedly has an
effect on the spiral flow length, for polymers with constant
MFI this effect is relatively small.
Figure 7: Effect of Density on Output Rate for Polymers
of the Same MFI
8
Qenos Technical Guides
FOI Document #18
INJECTION MOULDING 5
SPIRAL FLOW LENGTH — cm.
CONSTANT DENSITY
102
107
320
152
608
512
X0
..
."11
/
2*0
5° 2
7
20
/
220
SOO
240
404
220
420
MELT FLOW INDEX
Figure 9: Effect of MFI on the M ould Filling Properties
of Polyethylenes of Constant Density
f
A feature of the spiral flow test is that it can be applied to
all injection moulding materials. Figure 10 shows a chart
on which the spiral flow length has been plotted against
a series of cylinder temperatures for a range of polymers.
For most materials the temperatures used range from
the lowest at which a readable flow length can be obtained
to the highest that can be used without degrading the
material. However for polyethylenes of high MFI, with the
particular equipment used, the upper temperature was set
by the first observance of "flashing" (thin films of excess
polymer) on the moulded part.
i
1(1
— LOW-DENSITY POLYTHENES
— GP POLYSTYRENE
i
— POLYPROPYLENES
— NYLON
...'...." HIGH-DENSITY POLYTHENE
(Typical injactioa alouldno graila)
f
PLUNGER PRESSURE: 2000 13,//a!
(1400 lio.icin11
10
20
20
40
so
SPIRAL FLOW LENGTH — in.
Figure 10: Spiral Flow Curves for some Typical
Thermoplastics
Surface Finish
The second factor which may prevent moulding being
carried out at the peak of the output curve is the
requirement to obtain a good surface finish on the
moulded article. It can be seen from Figure 11 that the
gloss of a polyethylene moulding improves with increasing
cylinder temperature and that mouldings produced at the
lower temperatures have 'chevron' marks or rings on the
surface (see Figure 12). When mouldings with an even,
glossy surface are required it may be necessary to mould
at a cylinder temperature which is higher than that which
corresponds to the fastest output rate.
Qenos Technical Guides
9
FOI Document #18
5 INJECTION MOULDING
110
OUTPUTRATE - N UMBEROFMOULDINGSPERHOUR
100
oo
ao
70
LIMITED BY RATE
OF PLASTICISATION
60
Figure 12: Photo Illustrating 'Chevron Rings on an
Injection Moulded Surface
so
LIMITED BY RATE
OF COOLING
40
50
MEI 20
30
130
150
170
100
210
230
250
270
300
40
CYLINDER TEMPERATURE — "C
30
MFI 7
Figure 11: Variations of Surface Gloss of Mouldings with
Cylinder Temperature
Gloss is assessed both visually and by measuring the
light reflected from the surface of mouldings made
under standard conditions. By the latter method, gloss/
temperature curves can be plotted as shown in Figure 13.
This not only shows the effect of cylinder temperature on
gloss, but also the very marked effect of MFI. With a higher
MFI, high-gloss mouldings can be produced at a lower
cylinder temperature which allows for a faster output
(see Figure 13).
10
MFI 2
FO
"00
2'0
240
260
CYLINDER TEMPERATURE — °C
Figure 13: Effect of MFI and Temperature on Gloss
Qenos Technical Guides
FOI Document #18
INJECTION MOULDING 5
It can be concluded that a high MFI is the characteristic
mainly responsible for ease of moulding and high
output rates. The higher the MFI, the lower the cylinder
temperature which can be used to obtain adequate mould
filling and acceptable surface finish, and consequently, in
most cases, the higher the output will be. For resins with
a constant MFI, the degree to which an increase in density
leads to higher or lower outputs will depend mainly on the
size of the moulding in relation to the size of the machine.
For adequate melting of the granules, higher density
polyethylenes require higher cylinder temperatures than
do the lower density polyethylenes, and melting is more
likely to be a limiting factor.
Thus, as far as processing is concerned, the type of
polyethylene chosen should have as high an MFI as
possible. However, the choice of both MFI and density
must also take into account the physical properties
required in the finished moulding, and this subject is
discussed in the next section.
EFFECT OF MFI AND DENSITY ON THE
PROPERTIES OF POLYETHYLENE MOULDINGS
The physical properties of polyethylene which are of
particular importance in injection moulded articles are:
• Stiffness
• Impact properties
• Resistance to environmental stress cracking
• Resistance to mechanical stress cracking
Stiffness
The main factor determining the stiffness of a moulding
is the density of the polyethylene. Figure 14 shows
-how the stiffness (as measured by the 100 sec tensile
modulus) increases rapidly with increasing density. In
the lower density range a change in density of as little
as 0.007 g/cm3 will double the stiffness. Figure 14 also
shows the effect of temperature on stiffness.
MFI has virtually no effect on stiffness.
Qenos Technical Guides
sec. tensile modules at 0.2% strain — IbiinP x 104
Summary
110 130 ..
WC
120 110 100
99..
JO 20 -
WC
90 .50
40 30 .
20
OO'C
to
o
9915
_
:920
tom
0925
0420
0935
0940
0945
0950
0955
Density — g./c.c.
Figure 14: Variation of Stiffness and Density
with Temperature
Impact Properties
One of the outstanding properties of low density
polyethylene is its toughness; when subjected to impact it
will stretch and cold-draw before it breaks, rather than fail
in a glass-like manner. On the other hand, medium and
high density polyethylenes can fail in a way that is unknown
in low density polyethylenes. This type of failure is known
as brittle failure. It is quite different from the tough failure
of low density materials and is particularly noticeable in
mouldings which have sharp notches or scratches on
the surface. The usual impact tests for plastic materials
are difficult to apply to both brittle and tough types of
polyethylene and therefore a special test had to be
devised. For this an impact machine is used (see Figure 15)
in which small specimens (1 x lx 0.16 cm) are notched
to a depth of 0.020 cm and subjected to a blow from a
pendulum. The energy lost by the pendulum in striking the
specimens is termed the impact energy, although much
of this energy is expended in bending the specimen as
the pendulum swings past it. Polyethylene specimens are
rarely broken by the first blow, and therefore after a short
rest period they are given a second blow. The energy
absorbed by this second blow, expressed as a percentage
of the energy absorbed by the first blow, is termed the
fracture resistance. This quantity is found to be a useful
measure of the amount of damage caused by the first blow.
11
FOI Document #18
5 INJECTION MOULDING
Impact energy and fracture resistance depend on both
MFI and density, as may be seen from Figure 16. For some
polyethylenes the impact energy may increase at first with
increasing density and then decrease. This initial increase
in impact energy is due to the contribution from the energy
used in bending a specimen of increased stiffness.
Ultimately, however, the increase in density trends towards
brittleness, which becomes the dominant factor and
results in the measured impact energy falling to very low
levels. It can be seen quite clearly that in order to avoid
brittleness the higher density polyethylenes must have
a low MFI. Consequently, if toughness is required in the
higher density polyethylenes, poorer processability,
poorer mould filling and, in general, higher processing
temperatures will be required. It can also be seen that
with polyethylenes of lower density, a much wider choice
of MFI is possible without sacrificing toughness.
The dependence of brittle failure on density is also
complicated by the fact that the density of any polyethylene
is affected by its rate of cooling from the molten state.
This effect is illustrated opposite in Table 1.
Values for densities quoted in the literature usually refer
to specimens prepared in a standard way involving slow
cooling. In injection moulding, however, the polyethylene
is cooled rapidly and the molecular chains have no time
in which to pack into their equilibrium positions and
consequently the density is reduced to below the
equilibrium value. Subsequently, overtime, the density
increases towards its equilibrium value, a process which
is very slow but which is accelerated at elevated
temperatures. Provided that a polyethylene is chosen with
a density and MFI such that the polyethylene, when cooled
at the slowest rate found in injection moulding, lies in the
'tough' region in Figure 16, no detrimental change to the
mouldings impact strength will arise. But if a polyethylene
in the 'brittle' region is chosen (for example, a material
with a MFI of 20 g/10 min and a density greater than
0.927 g/cm3) mouldings produced under conditions of
rapid cooling will appear to be tough initially, because
of the decrease in density, but may become brittle as the
density increases over time.
Figure 15: Impact Machine Showing Sample Holder and
Process of Use
12
Qenos Technical Guides
FOI Document #18
INJECTION MOULDING 5
Table 1: Effect of Cooling Rate on the Density of Polyethylene (MFI 20)
Density g/cm3
Cooling Rate
Annealed at 140°C and cooled at 5°C per hour
0.918
0.923
0.927
Annealed at 140°C and cooled at 30°C per hour
0.916
0.921
0.925
Fast cooled in injection moulding
0.913
0.919
0.922
100
120
.=
=
_
_
,erz
—
_
10
CONSTANT DENSITY
'BRITTLE'
E
—
_
'TOUGH'
FRRA
EsiCsTU
TAF4EcE
E
=
—
20%
F.
7
"*"..........19 40%
099
041
092
17
094
045
DENSITY AT 23°C. — g./c.c.
Figure 16: Variations in the "Tough Brittle" Transition
(as defined by fracture resistance contours at 40% and
20%) with MFI and Density
2
20
MELT FLOW INDEX
Figure 17: Resistance of Polyethylenes of Different MFI
to Environment Stress Cracking
Environmental Stress Cracking
In practice it is important that high MFI polymers, even
of low density, should not be used for applications in
Environmental stress cracking is the name given to a
phenomenon by which polyethylene under high stresses
may crack in contact with certain active environments
such as detergents, fats and silicone fluids.
which they will be severely stressed when in contact with
active environments. For such applications a polyethylene
of low MFI is essential and the higher the density of the
polyethylene the lower the MFI must be.
The resistance of polyethylene to environmental stress
cracking decreases rapidly as the MFI is increased.
Figure 17 indicates how test specimens of polyethylenes
of different MFI and of constant density behave when
subjected to a severe stress in the presence of an active
environment. Comparison of polyethylenes of constant
MFI but of different densities is more complicated because
in such tests the specimens are tested under constant
strain and therefore the higher density polyethylenes
will be under greater stress because they are stiffer.
Nevertheless, the comparison is a valid one because in
many applications, for example, screwing down a bottle
closure or forcing a washing-up bowl into a sink, it is the
deformation which is constant rather than the stress.
A typical application for which a polyethylene of low MFI is
preferred in order to reduce the hazards of environmental
stress cracking is that of closures used in contact with
liquid detergents, soap solutions and certain cosmetics.
Qenos Technical Guides
It is important however not to exaggerate the seriousness
of environmental stress cracking. It has been found that
the majority of mouldings made from polyethylene are not
subjected to severe enough stressing in service to cause
failure, even though they may be in contact with active
environments. For example, most polyethylene housewares
are in daily contact with both detergents and fats, and yet
the externally applied stresses to which they are subjected
to are not sufficient to cause failure through environmental
stress cracking.
13
FOI Document #18
756
5 INJECTION MOULDING
Careful consideration needs to be made of the choice of
polymer that will meet the demands of the finished product
and the environment(s) that it will be exposed to (e.g. oils,
fats, alkalis, acids and temperature, etc.). To make the best
resin selection, customers are advised to discuss their
specific end product requirements with their Qenos
Technical Service Representative.
Mechanical Stress Cracking
Under certain conditions the moulding process itself
can create high levels of internal stress in polyethylene.
This is due to the semi-crystalline nature of the polymer
which enters the mould in a molten state and undergoes
crystallisation as the resin solidifies. The different
polyethylenes undergo different degrees of crystallisation
which is dependent on their molecular structure.
In general, the polyethylenes can be ranked in terms of
their crystalisability/shrinkage in the following order:
HDPE LLDPE ?_ LDPE
The internal stress that is also commonly referred to as
'frozen in strain' or 'residual strain' may cause similar
effects to those seen where polyethylene is exposed to
external stresses in service.
The occurrence of 'frozen in strain' is due to both the
crystalline nature of the resins used and also as a result of
the moulding conditions and the design of the finished part
(see Conditions for Moulding Polyethylene section on pg. 18).
Once a polyethylene has been selected (HDPE, LLDPE,
LDPE) for fabrication of the finished part, internal stresses
can be negated/minimised through careful mould design
and by controlling the processing conditions on the
injection moulding machine.
Many mouldings, however, are also subjected in service
to externally applied mechanical stresses which can cause
cracking. Examples of such mouldings are those containing
metal inserts (e.g. knobs) and those used for interference
applications (e.g. snap-on closures, ferrules or feet for
tubular furniture). For such finished parts careful selection
of the polymer is important. Within the polyethylenes a
balance is required between the MFI (e.g. for ease of
processing) and the density (e.g. which affects the level of
shrinkage) in order to minimise the level of internal stress.
Generally, higher density polyethylenes would require a
lower MFI and vice versa. For example, a polyethylene
of MFI 20 g/10 min should generally not exceed a density
of 0.918 g/cm3. Although such "rules of thumb" are only
14
general recommendations, other considerations of mould
design and the generation of weld lines in the finished part
are factors that need to be reviewed when assessing the
strength of the moulding.
For articles not expected to be stressed in service, cracking
caused by 'frozen-in strain' is the hazard to be avoided.
A polyethylene of higher MFI is preferable because it is
easier to mould such a polyethylene to give a low level of
'frozen-in strain'.
Summary
In general, polyethylenes of high MFI and low density
are most commonly used for injection moulding because
they give the highest outputs, have the best mould
filling properties, and give the glossiest mouldings. For
applications in which mouldings are likely to be stressed
in service, polyethylenes of low MFI must be used. If
increased stiffness is required, polyethylenes of higher
density are necessary, but these must have a lower MFI
to prevent them from becoming brittle and to improve
resistance to environmental and mechanical stress
cracking. For non-stressed applications 'frozen-in strain' is
the hazard to be avoided and a polyethylene of higher MFI
is preferred. Provided that these few simple principles are
followed, articles giving a long and satisfactory service
life can be moulded from polyethylene without difficulty.
SOME ASPECTS OF DESIGNING MOULDS
FOR POLYETHYLENE
A detailed examination of mould design is outside the
scope of this booklet. There are however, three problems
affecting mould design which, although not peculiar to low
density polyethylene, occur frequently with this material
and which can conveniently be discussed here. These are:
• Shrinkage
• Distortion
• Weld lines
Shrinkage of Polyethylene Mouldings
The influence of moulding conditions and the shape
of mouldings is so great that it is almost impossible to
predict the exact shrinkage of polyethylene mouldings.
It is recommended therefore that trials under controlled
moulding conditions should be carried out before the
mould is hardened and polished. The mould may then be
adjusted accordingly. To allow for any after-shrinkage the
dimensions of mouldings should not be checked until at
least 24 hours after removing the mouldings from the mould.
Qenos Technical Guides
FOI Document #18
INJECTION MOULDING 5
Measurements must be checked in all important
dimensions because mould shrinkage varies with the
direction of flow, and checking only one dimension and
applying proportional corrections to the others may lead
to major inaccuracies.
sm.
The following major variables affect mould shrinkage.
• Melt temperature: the higher the melt temperature,
the greater the shrinkage will be
• Mould temperature: the higher the mould temperature,
the greater the shrinkage will be
• Injection dwell time and injection pressure: shrinkage
will be smaller for longer injection dwell times and higher
pressures
• Thickness of section: the thicker the moulded section,
the slower the cooling and the greater the contraction of
the moulding will be
As Designed
As Molded
• Orientation: shrinkage will be greater in the direction
of flow than at right angles to it
• Density: shrinkage is greater with polyethylenes of higher
density e.g. a polyethylene of density 0.930 g/cm3 will
shrink more than a polyethylene of density 0.918 g/cm3
Boss in corner
causes sink
Thinner walls on boss,
eliminates sink
• Gating: shrinkage is usually greater when pin gates are
used than when sprue gates are used
C
Because the above variables have such a marked effect
on shrinkage, it is clear that in order to maintain accurate
dimensions, close control of moulding conditions is
essential. Cooling channels must provide adequate and
even control of mould temperature over the whole mould.
Cycle time control is of equal importance, especially for
precision work. Injection pressures should be controlled
and the values checked regularly on a gauge.
A point which must always be kept in mind when
specifications call for close moulding tolerances is that
the coefficient of thermal expansion of polyethylene is high
and that a change of 5°C in room temperature will alter the
length of a moulding by as much as 0.001 cm/cm.
Some examples of shrinkage are illustrated in Figure 18.
Because it is usually on small mouldings that close
dimensional control is required, Figure 18 shows where sink
marks and warping are likely to occur in such finished items.
Qenos Technical Guides
delop
Thick walls
causes sink, warp
& excess shrink
Thinner walls give
accurate parts
Figure 18: The Effects of Processing Conditions on
Shrinkage and Warping
15
FOI Document #18
5 INJECTION MOULDING
Distortion of Polyethylene Mouldings
Distortion or warping of polyethylene mouldings can
be a problem on flat articles which do not have a solid
rim or walls to keep the base firmly held in position.
The explanation of this warping is mainly due to polymer
orientation and differential crystallisation across the
moulding (see Figure 19).
•
-
I
Figure 19: Processing Conditions Causing Polymer
Orientation which Leads to Warping
When the mould is first filled, a hot moulding will be
made. As the mould fills, the long thread-like polyethylene
molecules would tend to be oriented in the direction of
flow i.e. radially outwards, but as the moulding cools a
radial shrinkage will occur which is greater than the
shrinkage at right angles to the radius. Thus when the
moulding is cold it will inevitably warp due to the difference
in the stresses generated in the part. All methods of
preventing the distortion of flat articles without rims or
walls depend, in essence, on reducing this difference.
Mould Design
To reduce the warping in articles, multiple pin gates must
be used. This system relies on reducing the length of each
radial flow path and inter-mingling the melt streams, and is
often adequate for low and medium density polyethylenes
(see Figure 20).
Figure 20: Photos Illustrating Multiple Pin Gating
and Fan Gating
16
Qenos Technical Guides
FOI Document #18
INJECTION MOULDING 5
For rectangular shapes the ideal gating arrangement is
a fan gate (see Figure 20) all along one edge so that flow
takes place mainly along the major axis. The moulding
will still shrink to a greater extent in the direction of flow,
causing the major axis to be proportionately shorter than
the minor axis when the moulding is cold, but it will not
distort. To position a gate at the end of a rectangular
article is relatively easy on small mouldings to be made
on multi-impression tools, but it is not so easy on large
single-impression moulds. Some machine manufacturers
can arrange for off-set injection points by altering the
nozzle position from the usual central point and this is
a very useful feature if large flat articles are to be made
from high or low density polyethylene.
Weld Lines
Choice of Polymer
Figure 21: Mouldings Illustrating the Formation of
Weld Lines When Two Melt Fronts Meet
The likelihood of warping increases rapidly with increasing
density of the polyethylene used: high density polyethylene
mouldings warp more than those of medium density, which
in turn warp more than those of low density polyethylene.
If flexibility in the moulding can be tolerated, a polyethylene
of low density (e.g. 0.916 g/cm3) will give the least
distortion. If the mouldings are not to be stressed and
physical strength is not important, e.g. sink trays and many
box lids, the best results are obtained from a low density
polymer of high MFI (22-70 g/10 min, according to the lack
of strength which can be tolerated).
Moulding Conditions
Obviously the ideal moulding conditions would be those
which give no orientation in the moulding and thus no
warping. In practice such conditions can never be
achieved. It has been found that long injection dwell
times and high pressures, because they reduce the overall
level of shrinkage, can often reduce warpage, but these
conditions give rise to packing stresses and may cause the
mouldings to split across the sprue. The best compromise
in moulding conditions has been found to consist of a very
high melt temperature (i.e. 50°C higher than that normally
used for a given polyethylene) and a very cold mould (i.e. as
cold as can be achieved).
Qenos Technical Guides
Weld lines can occur in any plastic moulding when the
melt stream is divided as it flows round some obstruction,
or can arise through non-uniform filling of the mould caused
by, for example, eccentricity of cores (see Figure 21).
Weld lines are particularly troublesome in polyethylene
mouldings which are stressed in service, because failures
are likely to occur some considerable time after the part
has been installed. With many plastics, weld lines are
immediately obvious as a physical weakness in the
moulding which is detectable by brittleness on impact
or flexing. With polyethylene, the fault may not appear
so serious, and it may only be when stress is applied over
a period of time in service, particularly in contact with
an active environment, that failure will occur. Weld lines
can be minimised by the use of high melt and mould
temperatures, and also by utilisation of high injection
pressures. Although care must be taken not to create
greater difficulties by introducing packing around the sprue.
A better solution however is to avoid weld line formation
wherever possible by suitable positioning of the gate. On
many bottle closures for example a centre pin gate can be
used instead of a side gate. The mould may cost more with
centre gates, but with bottle caps in particular, which are
stressed in an outwards direction, the advantages of
mouldings free from weld lines are great. In many cases
the additional strength conferred by centre gating will
permit the use of a polyethylene of high MFI which,
although poorer in resistance to environmental stress
cracking, will process easier and faster. Where articles
of cylindrical shape are highly stressed in an outwards
direction and centre gating is not possible, serious
consideration should be given to diaphragm or ring gating.
17
FOI Document #18
90
5 INJECTION MOULDING
Flow Weld Lines
These generally occur towards the end of the flow path
on a thin-walled article of large surface area, e.g. certain
types of buckets. They are caused by the dividing of the
advancing melt front into separate streams which fail
to fuse together when the mould is full. This effect is
aggravated by inadequate pressure on the melt or too low
a melt temperature. The weld lines formed may be barely
visible to the naked eye, but they can readily be detected
by immersing the moulding in carbon tetrachloride at a
temperature of 50 to 70°C where fissures will open up.
Such weld lines are quite common and cause splits in the
walls of thin containers (see Figure 22).
The aim of the moulder must be to choose, for each
particular material and moulding, the correct combination
of variables which will produce perfect mouldings as easily
and as quickly as possible. The position is somewhat
complicated by the fact that a moulding that looks perfect
may not in fact be so because of the presence of 'frozen-in
strain', and therefore the choice of moulding conditions
must take into account their effect, not only on the
appearance of the moulding, but also on 'frozen-in strain'.
In the following sections each variable will be discussed in
the light of these two considerations, together with other
relevant factors, such as the use of mould release agents.
Finally a table, summarising some common moulding faults,
their causes and remedies, is given (see Appendix 2).
Cylinder and Melt Temperatures
6.43
" \\"""\
56
8 16 24
48 56 \ 13
10111111101140\ddliglidd*
144411111‘
'131
Figure 22: Failure Due to Flow Weld Lines
CONDITIONS FOR MOULDING POLYETHYLENE
In the injection moulding process the moulder is able to
control several operating variables, each of which can
influence the quality of the mouldings or the rate at which
they are produced. These variables are:
• The temperature of the machine cylinder
• The temperature of the mould
• The 'injection variables', i.e. the injection pressure
and speed, and the cycle time
18
The melt temperature is the temperature of the
polyethylene as it enters the mould. Depending on
the grade of polyethylene being used, the temperature
should lie in the range 160-280°C. In practice, it is not
convenient to measure the melt temperature directly,
and it is therefore necessary to use the machine cylinder
temperature as a guide to the value of the melt
temperature. The important point to note is that the
cylinder temperature as indicated on the control panel
instruments is not necessarily the same as the melt
temperature, because the melt temperature depends on
the rate at which the material passes through the cylinder
and through the gate of the mould, as well as on the
cylinder temperature. For example, if the shot weight is
almost as large as the shot capacity and mouldings are
being produced very rapidly, the material will be in contact
with the heated cylinder for only a short time before being
injected and may not have time to reach the temperature
of the cylinder but may be as much as 30°C lower. On the
other hand, in a machine of larger capacity that is working
at slower output rates, the time of contact will be longer
and consequently a lower cylinder temperature can be
used and the difference between it and the melt
temperature can be reduced to about 5°C. Similarly, a
moulding containing a thick section will require a lower
cylinder temperature than will a moulding of equal weight
but of thinner section. This is because the thick moulding
will require a longer cooling time and thus a longer cycle
time than the thinner moulding; therefore the material will
be in contact with the heated cylinder for a longer time
and its temperature will more nearly approach that of the
cylinder. A less common cause for the melt temperature
to be different from the cylinder temperature is frictional
heating of the material as it passes through the gate;
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FOI Document #18
23
INJECTION MOULDING 5
if material is injected rapidly through a small gate the heat
generated may be sufficient to raise the melt temperature
above that of the cylinder.
From these examples it is clear that it is not possible to
predict the exact cylinder temperature that must be used
to obtain a given melt temperature, but that it is necessary
to choose a suitable cylinder temperature as a starting
point and then to make adjustments based on visual
inspection of the mouldings and on considerations of
'frozen-in strain'. For grades with MFI above 20 g/10 min
the suggested starting temperature is 210°C and for
grades with MFI below 20 g/10 min the suggested starting
temperature is 260°C.
When the cylinder temperature has been set, the injection
pressure and cycle time should be adjusted to the minimum
values consistent with the production of full mouldings,
and moulding should then be carried out for long enough
(usually 15-30 minutes) to enable conditions to settle down.
The mouldings should then be inspected and tested. Testing
should be conducted after conditioning for 24 hours,
preferably in a constant temperature environment.
Appearance of Mouldings
If the surface of the mouldings is dull or patchy, or contains
matt rings or 'chevron marks' (see Figure 12), this is an
indication that the melt temperature is too low, and the
cylinder temperature should be raised until mouldings with
a uniform, glossy finish are obtained. If the surface finish
is acceptable, but mouldings are tending to stick in the
mould, the melt temperature is probably too high and the
cylinder temperature should be reduced until the trouble
is eliminated. These procedures are effective for all grades
of Alkathene LDPE but it should be remembered that with
materials of MFI below 0.5 g/10 min the cycle time may
have to be rather long to allow the melt to reach the
required temperature.
Frozen-in Strain
At low moulding temperatures the melt viscosity is higher,
the mould fills relatively slowly, and the polyethylene
freezes quickly so that relatively little relaxation of the
polymer orientation can occur. It has been shown quite
conclusively, not only by laboratory tests but also by
extensive service trials, that mouldings made at low melt
temperatures can contain enough 'frozen-in strain' to
overcome the structural integrity of the part and result in
failure, whereas those made under optimum conditions are
perfectly satisfactory (see Figure 22).
It may be concluded that the optimum cylinder temperature
is the lowest at which full, glossy mouldings can be
obtained, and that under these conditions 'frozen in strain'
will be at a minimum. Too high a temperature will lead to
sticking and long cycles, and too low a temperature will
lead to strained mouldings.
Mould Temperature
The mould temperature chosen should be that at which
good mouldings can be produced with a minimum cycle
time. The colder the mould the faster the melt will cool
and the greater will be the tendency for 'frozen-in strain'
to develop. Therefore, to reduce 'frozen-in strain' a warm
mould is recommended and for the minimum amount
of strain, a heated mould (as hot as possible) would be
required. However, the use of a very hot mould would slow
down the cooling rate and thus not only prolong the
moulding cycle but also substantially increase the density
of the moulding. This is particularly true for mouldings
that contain thick sections. As explained in the Impact
Properties section (pg. 11), certain polyethylenes can,
under these conditions, be brought from the tough region
into the brittle region (see Figure 16). In practice, mould
temperatures in the range 30-50°C have been found
to offer the best compromise between the effects of
'frozen-in strain' and notch-sensitivity. Figure 23 shows
the variation of retraction with mould temperature for
a constant cylinder temperature.
Melt viscosity (and hence melt temperature) is the
most important factor determining 'frozen-in strain'.
As highlighted in Appendix 1 the presence of 'frozen-in
strain' is associated with orientation of the polyethylene
molecules as they are injected into the mould cavity. At
high temperatures the viscosity of the polyethylene is low
and the mould is filled rapidly: only the layer of material
immediately adjacent to the mould surface has frozen
before the mould is filled so that during cooling the
maximum relaxation of orientation can take place.
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FOI Document #18
5 INJECTION MOULDING
a
RETRACTION - %
7
3
50
50
70
ao
Figure 24 shows mouldings made from the same type of
polyethylene at the same cylinder temperature, but using
different injection dwell times and pressures. The samples
moulded at high pressure with a long dwell time appear
indistinguishable from those moulded under more
favourable conditions. But when the mouldings are cut
open, it can be seen that excessively high pressures and
long dwell times can result in a thickening of the base near
the sprue, which in extreme cases, can result in thickness
increases of approximately 30%. When the mouldings were
then subjected to an accelerated service test in an active
environment, the effects of too much packing constituted
a very serious cracking hazard.
MOULD TEMPERATURE —
Mould Filling Time
Figure 23: Variation of Retraction with Mould
Temperature (Cylinder Temperature is Constant)
Because of the importance of correct mould temperature
and the growing tendency to reduce cycle times it is
essential, as already remarked, that in the initial designing
of the mould, provisions should be made for efficient
cooling; unfortunately this is a feature which is all too
often overlooked with consequent difficulties in
subsequent operation.
Injection Variables
The injection variables will be considered under two
headings: injection pressure and dwell time; and mould
filling time.
Injection Pressure and Dwell Time
To produce good mouldings, both quickly and economically,
the injection pressure should be kept to a minimum and
the dwell time made as short as possible. Increasing the
packing of an additional volume of polyethylene into the
mould during the dwell time to compensate for the
shrinkage of the polyethylene due to crystallisation is also
important. The degree of packing should be kept to a
minimum because the excess polyethylene is forced into
the mould cavity when the melt has almost solidified and
therefore orientation introduced at this stage relaxes
slowly. This can result in a highly strained region being
formed near the sprue/gate. The strain may be sufficient
to initiate stress cracking and therefore the dwell time and
injection pressure must be kept to a minimum.
20
On some machines the injection speed can be varied
virtually independently of the injection pressure by
means of a flow control valve. In long, thin flow paths the
polyethylene will cool rapidly and this section will contain
a fairly high degree of strain. In addition, thin-walled
mouldings require higher pressures to fill the mould and,
therefore, packing may occur before the extremities of
the flow path have been reached. The remedy is to use a
higher melt temperature and as fast an injection speed as
possible. On the other hand, for thick-sectioned mouldings
it is often an advantage to reduce the speed of injection
so as to avoid 'jetting' and turbulence which will lead to
mouldings with a poor surface finish.
Summary
The moulding conditions necessary to produce good
mouldings with the best appearance and the lowest
amount of 'frozen-in strain' are:
• A melt temperature just high enough to give a glossy
surface to the moulding
• A mould temperature of about 30-50°C
• The minimum injection pressure and dwell time
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FOI Document #18
INJECTION MOULDING 5
normal injection dwell time
normal pressure
excessive injection dwell time
excessive pressure: note thickening
(a) before test
(b) After accelerated cracking test
Figure 24: Effect of Injection Pressure and Dwell Time on Polyethylene Mouldings
MOULDING FAULTS
Faults in polyethylene mouldings may be divided into two
classes: those that are obvious from visual inspection
and those arising from the presence of 'frozen-in strain' these can be detected only by testing. Appendix 2 lists the
obvious faults that can occur, with their possible causes
and remedies. Faults arising from 'frozen-in strain' have
already been dealt with earlier.
In using Appendix 2 it should be noted that because the
machine variables are interdependent a remedy that
involves the adjustment of any one machine variable may
Qenos Technical Guides
also necessitate adjustment of the others. Alteration of
the melt temperature should be gradual, in steps of 10°C,
and a full cylinder of material should be injected before
the results of any 10°C step are assessed. Alteration of
the cycle time (which affects the length of time the material
is in the cylinder and hence the melt temperature) should
also be carried out gradually. Enough time should be
allowed between successive adjustments to ensure that
steady conditions at any one setting are obtained before
the effect of that setting on the quality of the mouldings
is determined.
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FOI Document #18
5 INJECTION MOULDING
MOULD RELEASE AGENTS
Embossing
If the correct moulding conditions have been chosen,
polyethylene mouldings are unlikely to stick in the mould.
If they do, and the fault cannot be corrected by adjusting
the moulding conditions, mould lubricants such as
stearates or fatty amides may be used. Silicone oils and
greases may cause environmental stress cracking in
polyethylene mouldings and therefore before they are
used as mould release agents they should be tested with
the moulding to see if they are suitable. If any doubt exists
as to their suitability they should not be used.
A relief pattern on mouldings is easily achieved by cutting
the pattern in the mould. Conversely, a relief pattern on
the mould produces a corresponding recessed pattern
in the moulding. The embossed design can subsequently
be decorated by printing or by painting. A wide range of
textures and finishes can be obtained by this method.
DECORATING POLYETHYLENE MOULDINGS
There are several ways in which polyethylene mouldings
can be decorated. These fall into two classes: those
applied directly to the polyethylene surface; and those
which require some form of pre-treatment of the surface.
The following sections briefly deal with the various methods
of pre-treatment, decoration and also with tests for the
effectiveness of these processes.
Decorating Untreated Polyethylene
The following methods are commonly used:
• Hot stamping
• Labelling
Decorating Treated Polyethylene
Pre-treatment
Because polyethylene is non-polar and cannot be dissolved
in any known solvent at room temperature it is not possible
to directly apply conventional inks, paints and lacquers.
There are, however, several ways in which polyethylene can
be made polar. These are:
• Chlorination
• Chemical oxidation
• Flaming
• Electronic methods
Of these, chlorination is of little commercial importance,
and electronic methods are usually restricted to thin films.
Flaming is a versatile process which can handle any
surfaces which do not contain deep or intricately shaped
recesses. Chemical methods are not used so frequently, but
they are the most satisfactory for parts of complex design.
• Embossing
Flame Treatment
Hot Stamping
Basically, this method consists of pressing on to the
polyethylene a tape which is coated with pigment. Heat
and pressure are applied via a male die and the pigment
is released from the tape and fused into the polyethylene.
Stamping should preferably be carried out while the
moulding is still warm after being ejected from the die.
Because it is recessed, the coating obtained by hot
stamping has a good degree of scratch resistance. Other
advantages of this process are the absence of solvents
and negating the need for drying facilities.
Labelling
Labelling is an inexpensive way of achieving a very wide
range of effects. The choice of adhesive will depend on
whether the label is required to be permanently fixed or
easily removed.
Flaming a polyethylene moulding results in slight oxidation
of the surface. This provides a polar surface which is
required for good adhesion. The flame should be oxygen
rich, of constant length and should impinge on the surface
long enough to result in dulling of the surface. The exact
technique will vary according to the shape of the part being
treated. The essential point is that all parts of the surface
should be uniformly treated.
Chemical Treatment
Chemical methods of pre-treatment involving acid etching
are costly and often difficult to operate, but they are
used for complicated parts and for parts to be vacuum
metallised. Basically the procedure is simple:
• The moulding is immersed for 30 sec to 2 min in an
acidified dichromate solution (a typical solution is
100 cm3 of concentrated sulphuric acid, 50 cm3 water
and 15 g of potassium dichromate),
• Removed from the bath, washed thoroughly and dried.
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FOI Document #18
INJECTION MOULDING 5
The big disadvantage of this method is the need to handle
acid solutions; the main advantage is that every part of the
surface, provided it is clean, is treated in the same way.
Tests for Pre-treatment
It is obviously desirable to be able to test the effectiveness
of any pre-treatment to ensure good adhesion of the
finished coating. Several tests can be used, of which those
based on 'wettability' of the surface are popular because
of their simplicity.
Peel Test
This test involves the use of a solvent-free, pressure
sensitive tape. Such a tape has little affinity for an
untreated polyethylene surface and is removed fairly easily,
whereas it will bond strongly to a treated surface. A
suitable tape is No. 850 supplied by Minnesota Mining and
Manufacturing Co. Ltd. (3M). The tape is rolled on to the
moulding by means of a rubber roller and is then peeled off
under standard conditions using a tensometer. By noting
the 'peel strength' recorded, a quantitative indication of the
treatment level can be obtained. Since decorative coatings
vary in their adhesion to polyethylene surfaces, there is no
basic correlation between peel strength and adhesion.
However, it has been found that treatments giving peel
strengths greater than about 120 g/cm will result in
satisfactory adhesion of most coatings.
Screen printing has the great advantage of low capital
cost, particularly when the operation is done manually.
Fully automatic units are available. The main disadvantage
of silk-screening is that no more than one colour can
be applied at one pass. If additional colours need to be
applied, then the moulding must be dried before the next
colour is applied.
Vacuum Metallising
In vacuum metallising a thin continuous layer of metal
is deposited onto a prepared surface by vaporising the
metal under high vacuum and condensing it on the
surface. In practice, a lacquer is applied to the pre-treated
polyethylene as a base coat. This serves to smooth out any
imperfections and also acts as a key for the metallic film.
The metallic film (usually of aluminium) is deposited, and
a top coat of protective lacquer is applied. Low density
polyethylene articles are successfully finished in this way.
Although the flexibility of the material is a disadvantage.
Tests for Finished Coatings
Two simple but effective tests are the Scratch test and the
Scotch Tape test.
Scratch Test
A good idea of the adhesion of a coating can be obtained
by scratching it with a finger nail or a knife to see if it flakes.
Decorating Methods for Treated Surfaces
Scotch Tape Test
Two methods that can be used are:
In this test a length of pressure-sensitive tape such as
Scotch Tape supplied by 3M is stuck on to the polyethylene
moulding and then pulled off, slowly at first and then more
quickly. The level of adhesion of the coating can be judged
qualitatively by the degree, if any, to which the coating is
removed.
• Silk-screen printing
• Vacuum metalising
Silk-screening
This is essentially a stencilling process in which the stencil
takes the form of a silk, nylon or metal screen which has
been made porous, by a photographic process, over areas
corresponding to the design to be printed. The screen
is held taut in a wooden frame which also serves as a
reservoir for the ink. In use, the screen, with ink on its
upper surface, is placed in contact with the article and a
rubber 'squeegee' is drawn over the screen, thus forcing
ink through the porous area on to the article.
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FOI Document #18
5 INJECTION MOULDING
APPENDIX 1— FROZEN-IN STRAIN
It is believed that 'frozen-in strain' develops in the following
way. As the polyethylene melt is injected into the mould
cavity, it is subjected to high shear forces which produce
a certain degree of uncoiling of the molecular chains and
causes them to be oriented in the direction of flow. The
nearer the melt is to the mould surface, the greater will be
the shear stress and the greater the orientation. Because
the material nearest to the mould surface cools more
rapidly than the material in the interior, this orientation
is unable to relax and becomes frozen into position. Thus
a highly oriented layer is formed, the thickness of which
depends on the temperatures of the melt and of the mould
surface. On the other hand, the material on the inside is
insulated from the cool mould by a layer of polyethylene
and consequently it remains molten until near the end of
the moulding cycle. Not only is this material less oriented
during mould filling, but most of the orientation that does
occur can relax during the cooling stage. Therefore an
injection moulded section has a composite structure
consisting of a skin which is highly strained and inner
layers containing a much lower degree of molecular
orientation. Figure 25 is a greatly magnified picture of
a section cut through an injection moulding which shows
clearly the different layers that are formed. In service, the
oriented chains will tend to revert to their normal, coiled
configuration and this tendency is reflected in a reduction
in the dimensions of a specimen parallel to the direction
of flow and an increase in the dimensions at right angles
to the flow. If these dimensional changes are resisted by
the shape of the moulding, mechanical forces arise which
can produce internal stresses large enough to cause
cracking in the presence of an active environment.
If a highly strained surface comes into contact with an
active environment such as synthetic detergents or fat,
a small crack may develop which is likely to propagate
rapidly, especially at elevated temperatures. Depending
on the particular type of polyethylene, either cracks may
develop throughout the whole section or failure may be
restricted to surface peeling.
Figure 25: A Section from a Polyethylene Moulding,
Showing the Layered Structure
At elevated temperatures the tendency for the oriented
molecules to revert to their normal configuration is
increased and some measure of the degree of orientation
can be obtained by cutting specimens from a moulding and
measuring the percentage retraction which takes place in
the direction of flow when the specimens are heated. A
large retraction indicates a high level of 'frozen-in strain'.
24
Qenos Technical Guides
FOI Document #18
PE grade has insufficient impact strength
Use lower flow and/or lower density grade of PE
Excessive orientation
Increase melt temperature
Inadequate thickness
Increase thickness of moulding
Insufficient venting
Increase venting
Burn marks.
Carbonised
material at end
of flow path
Injection speed too high
Reduce injection speed
Melt temperature too high
Reduce barrel and nozzle temperature settings
Delamination
Incompatible masterbatch
Ensure PE based masterbatch is used
Demoulding
difficulties
Poor design, insufficient draft angles
Increase draft angles, incorporate "slip"additive
Over packing
Reduce injection speed and or second stage time/
pressure, use higher flow PE grade
Excessive second stage
Reduce second stage pressure and/or time
Variation in mould cooling
Increase cooling channels in difficult to cool areas
Sink marks
Increase second stage pressure and or time
Gate freezing off too quickly
Increase gate size
PE melt flow index too high
Change to a low flow grade of PE
Excessive injection speed
Reduce injection speed
Back pressure too low
Increase back pressure
Poor colour
homogenisation
Masterbatch not compatible
Ensure PE based masterbatch is used
Barrel size too small, insufficient shots in barrel
Move to a larger machine
Masterbatch add rate too low
Use masterbatch with lower pigment concentration
at higher add rate
Temperature too low
Increase temperature settings
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FOI Document #18
5 INJECTION MOULDING
Problem/Issue
Cause(s)
Potential Solution(s)/Action(s)
Short shots.
PE melt flow index too low
Change to higher melt flow index grade
Incompletely
Melt temperature too low
Increase melt temperature.
Inadequate vent size
Increase venting
Inadequate thickness
Increase thickness
Insufficient injection speed
Increase injection speed
Insufficient gating
Increase gate size or number
Melt temperature too low
Increase temperature settings
Flow of polymer too low
Use higher melt flow grade
Injection speed too low
Increase injection speed
Gate(s) too far from weld line
Move gate or increase number of gates
filled mouldings
Weak weld lines
Disclaimer
The proposed solutions in this guide are based on conditions that are typically encountered in the manufacture of products from polyethylene.
Other variables or constraints may impact the ability of the user to apply these solutions. Qenos also refers the user to the disclaimer at the beginning
of this document.
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FOI Document #18
21
INJECTION MOULDING 5
BIBLIOGRAPHY/FURTHER READING
1. Rosato, D. V.; Rosato, D. V.; Rosato, M. G.; Injection Moulding Handbook (3rd Ed.), Kluwer Academic Publishers, 2000.
2. Johannaber, F.; Injection Moulding Machines - A User's Guide, (4th Ed.), Hanser Verlag, 2008.
3. Bryce, D. M.; Plastic Injection Moulding - Manufacturing process fundamentals, Society of Manufacturing
Engineers, 1996.
4. Osswald, T. A.; Turnig, L.; Gramann, P. J.; Injection Moulding Handbook, Hanser Verlag, 2008.
5. Potsch, G.; Michaeli, W.; Injection Moulding An Introduction, (2nd Ed.), Hanser Verlag, 2008.
6. Rueda, D. R.; Balta Calleja, F. J.; Bayer, R. K.; J. Mat Sci, 16, 3371, 1981.
Influence of processing conditions on the structure and surface microhardness of injection-moulded polyethylene.
Issued January 2014.
Qenos Technical Guides
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FOI Document #18
Oenos
Qenos Pty. Ltd.
ABN: 62 054 196 771
Cnr Kororoit Creek Road & Maidstone Street,
Altona Victoria 3018, Australia
1: 1800 063 573 F: 1800 638 981
cienos.com
PA
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