MIG 180 Operating manual

MIG 180 Operating manual
MIG 180
Operating manual
BOC Smootharc MIG 180 Operating manual
Welcome to a better way of welding.
This operating manual provides the basic knowledge required for MIG/
MAG welding, as well as highlighting important areas of how to operate
the Smootharc MIG 180 machine.
With normal use and by following these recommended steps, your
Smootharc MIG 180 machine can provide you with years of troublefree service. Smootharc equipment and technical support is available
through the national BOC Customer Service Centre or contact your local
Gas & Gear outlet.
Important Notice
This document has been prepared by BOC Limited ABN 95 000 029 729 (‘BOC’), as general information and does not contain and is not to be taken as containing any specific recommendation. The document has been prepared in good faith
and is professional opinion only. Information in this document has been derived from third parties, and though BOC believes it to be reliable as at the time of printing, BOC makes no representation or warranty as to the accuracy, reliability or
completeness of information in this document and does not assume any responsibility for updating any information or correcting any error or omission which may become apparent after the document has been issued. Neither BOC nor any of
its agents has independently verified the accuracy of the information contained in this document. The information in this document is commercial in confidence and is not to be reproduced. The recipient acknowledges and agrees that it must
make its own independent investigation and should consider seeking appropriate professional recommendation in reviewing and evaluating the information. This document does not take into account the particular circumstances of the recipient
and the recipient should not rely on this document in making any decisions, including but not limited to business, safety or other operations decisions. Except insofar as liability under any statute cannot be excluded, BOC and its affiliates,
directors, employees, contractors and consultants do not accept any liability (whether arising in contract, tort or otherwise) for any error or omission in this document or for any resulting loss or damage (whether direct, indirect, consequential
or otherwise) suffered by the recipient of this document or any other person relying on the information contained herein. The recipient agrees that it shall not seek to sue or hold BOC or their respective agents liable in any such respect for the
provision of this document or any other information.
BOC Smootharc MIG 180 Operating manual
1.0Recommended Safety Guidelines and Precautions
1.3 1.4
Health Hazard Information
Personal Protection
Electrical shock User Responsibility
2.0 MIG/MAG Operating Manual
2.1Introduction to Metal Inert Gas (MIG) & Metal Active Gas (MAG)
2.2Introduction to Flux Cored Arc Welding (FCAW)
2.3Introduction to Metal Cored Arc Welding (MCAW)
2.4 Modes of metal transfer 2.5Fundamentals of MIG/MAG, FCAW and MCAW
2.6 4T/2T Trigger Latch Selection
3.0 General Welding Information
Recommended Welding Parameters for MIG/MAG
4.0 Correct Application Techniques
5.0 Package Contents
6.0 Smootharc MIG 180 Installation
Installation for MIG/MAG process
7.0 Control panel
8.0 Smootharc MIG 180 Operation
Starting up
Operation instruction
9.0 Troubleshooting and Fault Finding
MIG/MAG functions
10.0 Periodic Maintenance
10.1 Power Source
11.0 Technical Specifications
12.0 Warranty Information
Terms of Warranty Limitations on Warranty
Warranty Period
Warranty Repairs
BOC Smootharc MIG 180 Operating manual
1.0Recommended Safety Guidelines
and Precautions
Diagram and safety explanation
Electrical safety alert
Welding electrode causing electric shock
Fumes and gases coming from welding process
Welding arc rays
Some safety precautions BOC
recommends are as follows:
• Repair or replace defective cables immediately.
Read instruction manual
• Never watch the arc except through
lenses of the correct shade.
• In confined spaces, adequate ventilation
and constant observation are essential.
Become trained
Wear dry, insulated gloves
• Leads and cables should be kept clear
of passageways.
• Keep fire extinguishing equipment at a handy location
in the workshop.
• Keep primary terminals and live parts effectively covered.
Insulate yourself from work and ground
• Never strike an arc on any gas cylinder.
• Never use oxygen for venting containers.
Disconnect input power before working on equipment
Keep head out of fumes
Use forced ventilation or local exhaust to remove fumes
Use welding helmet with correct shade of filter
BOC Smootharc MIG 180 Operating manual
1.1 Health Hazard Information
The actual process of welding is one that can cause a variety of hazards.
All appropriate safety equipment should be worn at all times, i.e.
headwear, hand and body protection. Electrical equipment should be
used in accordance with the manufacturer’s recommendations.
The process produces ultra violet rays that can injure and cause
permanent damage. Fumes can cause irritation.
Arc rays are dangerous to uncovered skin.
Welding fumes and gases are dangerous to the health of the operator
and to those in close proximity. The aggravation of pre-existing
respiratory or allergic conditions may occur in some workers. Excessive
exposure may cause conditions such as nausea, dizziness, dryness and
irritation of eyes, nose and throat.
• Fumes from the welding of some metals could have an adverse effect
on your health. Don’t breathe them in. If you are welding on material
such as stainless steel, nickel, nickel alloys or galvanised steel, further
precautions are necessary.
• Wear a respirator when natural or forced ventilation is insufficient.
Eye protection
A welding helmet with the appropriate welding filter lens for the
operation must be worn at all times in the work environment. The
welding arc and the reflecting arc flash gives out ultraviolet and infrared
rays. Protective welding screen and goggles should be provided for
others working in the same area.
Recommended filter shades for arc welding
Less than 150 amps
150 to 250 amps
250 to 300 amps
300 to 350 amps
Over 350 amps
Shade 10*
Shade 11*
Shade 12
Shade 13
Shade 14
1.2 Personal Protection
*Use one shade darker for aluminium.
Confined space welding should be carried out with the aid of a fume
respirator or air supplied respirator as per AS/NZS 1715 and AS/NZS 1716
Suitable clothing must be worn to prevent excessive exposure to UV
radiation and sparks. An adjustable helmet, flameproof loose-fitting
cotton clothing buttoned to the neck, protective leather gloves, spats,
apron and steel capped safety boots are highly recommended.
• You must always have enough ventilation in confined spaces. Be alert
to this at all times.
• Keep your head out of the fumes rising from the arc.
BOC Smootharc MIG 180 Operating manual
Back view of typical cylinder valve.
Operator wearing personal
protective equipment (PPE)
in safe position.
Cylinder safety diagram
Cylinder valve hand-wheel
Bursting disc
Ten points about cylinder safety
Always read the labels and Safety Data Sheet (SDS) before use.
Store cylinders upright and use in well‑ventilated, secure areas away
from pedestrian or vehicle thoroughfares.
Ensure cylinders are appropriately secured and guarded against
being knocked violently or being allowed to fall.
Wear safety shoes, glasses and gloves when handling, connecting
and using cylinders.
Ensure cylinders are appropriately restrained to mechanical lifting/
handling devices prior to movement.
Keep in a cool, well-ventilated area, away from heat sources, sources
of ignition and combustible materials, especially flammable gases.
Keep full and empty cylinders separate.
Keep ammonia-based leak detection solutions, oil and grease away
from cylinders and valves.
Never use force when opening or closing valves.
Never repaint or disguise markings and damage on cylinders.
If damaged, return cylinders to BOC immediately.
Cylinder valve safety
When working with cylinders or operating cylinder valves, ensure
that you wear appropriate protective clothing – gloves, boots and
safety glasses.
Ensure cylinder value is closed before moving or disconnecting
Before operating a cylinder valve
Ensure that the system you are connecting the cylinder into is suitable for
the gas and pressure involved.
Cylinder valves should not be open unless a pressure regulator has
been fitted.
Ensure that any accessories (such as hoses attached to the cylinder valve,
or the system being connected to) are securely connected. A hose, for
example, can potentially flail around dangerously if it is accidentally
pressurised when not restrained at both ends.
Stand to the side of the cylinder so that neither you nor anyone else is
in line with the back of the cylinder valve. This is in case a back-plug
is loose or a bursting disc vents. The correct stance is shown in the
diagram above.
When operating the cylinder valve
Open it by hand by turning the valve hand-wheel anti-clockwise. Use
only reasonable force.
Ensure that no gas is leaking from the cylinder valve connection or
the system to which the cylinder is connected. DO NOT use ammoniabased leak detection fluid as this can damage the valve. Approved leak
detection fluid, can be obtained from a BOC Gas & Gear centre.
When finished with the cylinder, close the cylinder valve by hand
by turning the valve hand-wheel in a clockwise direction. Use only
reasonable force.
Remember NEVER tamper with the valve.
If you suspect the valve is damaged, DO NOT use it. Report the issue to
BOC and arrange for the cylinder to be returned to BOC.
BOC Smootharc MIG 180 Operating manual
1.3 Electrical shock
• Never touch ‘live’ electrical parts.
BOC stocks a huge range of personal protective equipment. This,
combined with BOC’s extensive Gas and Gear network, ensures fast,
reliable service throughout the South Pacific.
• Always repair or replace worn or damaged parts.
• Disconnect power source before performing any maintenance
or service.
• Earth all work materials.
• Never work in moist or damp areas.
Avoid electric shock by:
• Wearing dry insulated boots.
PLEASE NOTE that under no circumstances should any
equipment or parts be altered or changed in any way from the
standard specification without written permission given by
BOC. To do so, will void the Equipment Warranty.
• Wearing dry leather gloves.
• Working on a dry insulated floor where possible.
1.4 User Responsibility
• Read the Operating Manual prior to installation of this machine.
• Unauthorised repairs to this equipment may endanger the technician
and operator and will void your warranty. Only qualified personnel
approved by BOC should perform repairs.
• Always disconnect mains power before investigating
equipment malfunctions.
• Parts that are broken, damaged, missing or worn should be
replaced immediately.
• Equipment should be cleaned periodically.
Further information can be obtained from Welding Institute of Australia
(WTIA) Technical Note No.7.
Health and Safety Welding
Published by WTIA,
PO Box 6165 Silverwater NSW 2128
Phone (02) 9748 4443
BOC Smootharc MIG 180 Operating manual
2.0 MIG/MAG Operating Manual
Typical MIG/MAG set up
Torch trigger
Gas diffuser
Contact tip
Welding wire
Weld pool
2.1Introduction to Metal Inert Gas (MIG)
& Metal Active Gas (MAG)
• Argon with oxygen mixtures (MAG)
MIG/MAG welding embraces a group of arc welding processes in which
a continuous electrode (the wire) is fed by powered feed rolls (wire
feeder) into the weld pool. An electric arc is created between the tip of
the wire and the weld pool. The wire is progressively melted at the same
speed at which it is being fed and forms part of the weld pool. Both the
arc and the weld pool are protected from atmospheric contamination by
a shield of inert (non-reactive) gas, which is delivered through a nozzle
that is concentric with the welding wire guide tube.
Each gas or gas mixture has specific advantages and limitations. Other
forms of MIG/MAG welding include using a flux-cored continuous
electrode and carbon dioxide shielding gas, or using self-shielding fluxcored wire, requiring no shielding.
MIG/MAG welding is usually carried out with a handheld torch as a semiautomatic process. The MIG/MAG process can be suited to a variety of job
requirements by choosing the correct shielding gas, electrode (wire) size
and welding parameters. Welding parameters include the voltage, travel
speed, arc (stick-out) length and wire feed rate. The arc voltage and wire
feed rate will determine the filler metal transfer method.
How it Works
Flux-cored arc welding (FCAW) uses the heat generated by a DC electric
arc to fuse the metal in the joint area, the arc being struck between a
continuously fed consumable filler wire and the workpiece, melting both
the filler wire and the workpiece in the immediate vicinity. The entire arc
area is covered by a shielding gas, which protects the molten weld pool
from the atmosphere.
This application combines the advantages of continuity, speed,
comparative freedom from distortion and the reliability of automatic
welding with the versatility and control of manual welding. The process
is also suitable for mechanised set-ups, and its use in this respect
is increasing.
FCAW is a variant of the MIG/MAG process and while there are many
common features between the two processes, there are also several
fundamental differences.
MIG/MAG welding can be carried out using solid wire, flux cored, or a
copper-coated solid wire electrode. The shielding gas or gas mixture may
consist of the following:
• Argon (MIG)
• Carbon dioxide (MAG)
• Argon and carbon dioxide mixtures (MAG)
• Argon with helium mixtures (MIG)
2.2Introduction to Flux-Cored
Arc Welding (FCAW)
As with MIG/MAG, direct current power sources with constant voltage
output characteristics are normally employed to supply the welding
current. With flux-cored wires the terminal that the filler wire is
connected to depends on the specific product being used, some wires
running electrode positive, others running electrode negative. The work
return is then connected to the opposite terminal. It has also been found
that the output characteristics of the power source can have an effect on
the quality of the welds produced.
BOC Smootharc MIG 180 Operating manual
Extended self shielded flux cored wire nozzle
The wire feed unit takes the filler wire from a spool, and feeds it
through the welding torch, to the arc at a predetermined and accurately
controlled speed. Normally, special knurled feed rolls are used with fluxcored wires to assist feeding and to prevent crushing the consumable.
cored wire is much smaller than that of a solid MIG/MAG wire. This
means that the electrical resistance within the flux cored wire is higher
than with solid MIG/MAG wires and it is this higher electrical resistance
that gives this type of wire some of its novel operating properties.
Unlike MIG/MAG, which uses a solid consumable filler wire, the
consumable used in FCAW is of tubular construction, an outer metal
sheath being filled with fluxing agents plus metal powder. The flux fill is
also used to provide alloying, arc stability, slag cover, de-oxidation, and,
with some wires, gas shielding.
One often-quoted property of fluxed cored wires are their higher
deposition rates than solid MIG/MAG wires. What is often not explained
is how they deliver these higher values and whether these can be
utilised. For example, if a solid MIG/MAG wire is used at 250 amps,
then exchanged for a flux cored wire of the same diameter, and welding
power source controls are left unchanged, then the current reading
would be much less than 250 amps, perhaps as low as 220 amps. This
is because of Ohms Law that states that as the electrical resistance
increases if the voltage remains stable then the current must fall.
In terms of gas shielding, there are two different ways in which this may
be achieved with the FCAW process.
• Additional gas-shielding supplied from an external source, such as a gas
• Production of a shielding gas by decomposition of fluxing agents within
the wire, self-shielding
Gas shielded wires are available with either a basic or rutile flux fill,
while self-shielded wires have a broadly basic-type flux fill. The flux
fill dictates the way the wire performs, the properties obtainable, and
suitable applications.
Gas-shielded Operation
Many cored wire consumables require an auxiliary gas shield in the same
way that solid wire MIG/MAG consumables do. These types of wire are
generally referred to as ‘gas-shielded’.
Using an auxiliary gas shield enables the wire designer to concentrate on
the performance characteristics, process tolerance, positional capabilities,
and mechanical properties of the products.
In a flux cored wire the metal sheath is generally thinner than that of
a self-shielded wire. The area of this metal sheath surrounding the flux
To bring the welding current back to 250 amps it is necessary to
increase the wire feed speed, effectively increasing the amount of
wire being pushed into the weld pool to make the weld. It is this affect
that produces the ‘higher deposition rates’ that the flux cored wire
manufacturers claim for this type of product. Unfortunately in many
instances the welder has difficulty in utilising this higher wire feed speed
and must either increase the welding speed or increase the size of the
weld. Often in manual applications neither of these changes can be
implemented and the welder simply reduces the wire feed speed back
to where it was and the advantages are lost. However, if the process
is automated in some way then the process can show improvements in
It is also common to use longer contact tip to workplace distances with
flux cored arc welding than with solid wire MIG/MAG welding and this
also has the effect of increasing the resistive heating on the wire further
accentuating the drop in welding current. Research has also shown
that increasing this distance can lead to an increase in the ingress of
BOC Smootharc MIG 180 Operating manual
Process Schematic Diagram for MIG/MAG, FCAW and MCAW
Gas hose
Continous wire
Wire feed unit
Power cable
Torch conduit
Gas cylinder
Welding torch
Power source
Earth clamp
Return cable
nitrogen and hydrogen into the weld pool, which can affect the quality of
the weld.
Flux-cored arc welding has a lower efficiency than solid wire MIG/
MAG welding because part of the wire fill contains slag-forming agents.
Although the efficiency varies differs by wire type and manufacturer, it is
typically between 75–85%.
Flux-cored arc welding does, however, have the same drawback as solid
wire MIG/MAG in terms of gas disruption by wind, and screening is
always necessary for site work. It also incurs the extra cost of shielding
gas, but this is often outweighed by gains in productivity.
Self-shielded Operation
There are also self-shielded consumables designed to operate without an
additional gas shield. In this type of product, arc shielding is provided by
gases generated by decomposition of some constituents within the flux
fill. These types of wire are referred to as ‘self-shielded’.
If no external gas shield is required, then the flux fill must provide
sufficient gas to protect the molten pool and to provide de-oxidisers and
nitride formers to cope with atmospheric contamination. This leaves less
scope to address performance, arc stabilisation, and process tolerance, so
these tend to suffer when compared with gas shielded types.
Wire efficiencies are also lower, at about 65%, in this mode of operation
than with gas-shielded wires. However, the wires do have a distinct
advantage when it comes to site work in terms of wind tolerance, as
there is no external gas shield to be disrupted.
When using self-shielded wires, external gas supply is not required and,
therefore, the gas shroud is not necessary. However, an extension nozzle
is often used to support and direct the long electrode extensions that are
needed to obtain high deposition rates.
2.3Introduction to Metal-Cored
Arc Welding (MCAW)
How it Works
Metal-cored arc welding (MCAW) uses the heat generated by a DC
electric arc to fuse metal in the joint area, the arc being struck between a
continuously fed consumable filler wire and the workpiece, melting both
the filler wire and the workpiece in the immediate vicinity. The entire arc
area is covered by a shielding gas, which protects the molten weld pool
from the atmosphere.
As MCAW is a variant of the MIG/MAG welding process there are many
common features between the two processes, but there are also several
fundamental differences.
As with MIG/MAG, direct current power sources with constant voltage
output characteristics are normally employed to supply the welding
current. With metal-cored wires the terminal the filler wire is connected
to depends on the specific product being used, some wires are designed
to run on electrode positive, others preferring electrode negative, and
some which will run on either. The work return lead is then connected
to the opposite terminal. Electrode negative operation will usually give
better positional welding characteristics. The output characteristics of the
power source can have an effect on the quality of the welds produced.
The wire feed unit takes the filler wire from a spool or bulk pack, and
feeds it through the welding torch, to the arc at a predetermined and
accurately controlled speed. Normally, special knurled feed rolls are used
with metal-cored wires to assist feeding and to prevent crushing the
Unlike MIG/MAG, which uses a solid consumable filler wire, the
consumable used in MCAW is of tubular construction, an outer metal
BOC Smootharc MIG 180 Operating manual
Schematic of Dip Transfer
Short circuit
Arc re-ignition
Arc established
Arc gap shortens
Short circuit
Current (A)
Voltage (V)
Short circuit cycle
sheath being filled entirely with metal powder except for a small amount
of non-metallic compounds. These are added to provide some arc
stability and de-oxidation.
MCAW consumables always require an auxiliary gas shield in the
same way that solid MIG/MAG wires do. Wires are normally designed
to operate in argon-carbon dioxide or argon-carbon dioxide-oxygen
mixtures or carbon dioxide. Argon rich mixtures tend to produce lower
fume levels than carbon dioxide.
As with MIG/MAG, the consumable filler wire and the shielding gas are
directed into the arc area by the welding torch. In the head of the torch,
the welding current is transferred to the wire by means of a copper alloy
contact tip, and a gas diffuser distributes the shielding gas evenly around
a shroud which then allows the gas to flow over the weld area. The
position of the contact tip relative to the gas shroud may be adjusted to
limit the minimum electrode extension.
Modes of metal transfer with MCAW are very similar to those obtained
in MIG/MAG welding, the process being operable in both ‘dip transfer’
and ‘spray transfer’ modes. Metal-cored wires may also be used in
pulse transfer mode at low mean currents, but this has not been widely
2.4 Modes of metal transfer
The mode or type of metal transfer in MIG/MAG and MCAW welding
depends upon the current, arc voltage, electrode diameter and type of
shielding gas used. In general, there are four modes of metal transfer.
Modes of metal transfer with FCAW are similar to those obtained in MIG/
MAG welding, but here the mode of transfer is heavily dependent on the
composition of the flux fill, as well as on current and voltage.
Arcing cycle
The most common modes of transfer in FCAW are:
• Dip transfer
• Globular transfer
• Spray transfer
• Pulsed arc transfer operation has been applied to flux-cored wires but,
as yet, is not widely used because the other transfer modes are giving
users what they require, in most cases.
Dip Transfer
Also known as short-circuiting arc or short-arc, this is an all-positional
process, using low heat input. The use of relatively low current and arc
voltage settings cause the electrode to intermittently short-circuit with
the weld pool at a controlled frequency. Metal is transferred by the wire
tip actually dipping into the weld pool and the short-circuit current is
sufficient to allow the arc to be re-established. This short-circuiting mode
of metal transfer effectively extends the range of MIG/MAG welding to
lower currents so thin sheet material can readily be welded. The low
heat input makes this technique well-suited to the positional welding
of root runs on thick plate, butt welds for bridging over large gaps and
for certain difficult materials where heat input is critical. Each shortcircuit causes the current to rise and the metal fuses off the end of the
electrode. A high short-circuiting frequency gives low heat input. Dip
transfer occurs between ±70-220A, 14–23 arc volts. It is achieved using
shielding gases based on carbon dioxide and argon.
Metal-cored wires transfer metal in dip mode at low currents just like
solid MIG/MAG wires. This transfer mode is used for all positional work
with these types of wire.
BOC Smootharc MIG 180 Operating manual
Schematic of Globular Transfer
Schematic of Spray Transfer
Gas shroud
Shielding gas
Large droplet
Globular Transfer
Metal transfer is controlled by slow ejection resulting in large, irregularlyshaped ‘globs’ falling into the weld pool under the action of gravity.
Carbon dioxide gas drops are dispersed haphazardly. With argon-based
gases, the drops are not as large and are transferred in a more axial
direction. There is a lot of spatter, especially in carbon dioxide, resulting
in greater wire consumption, poor penetration and poor appearance.
Globular transfer occurs between the dip and spray ranges. This mode of
transfer is not recommended for normal welding applications and may
be corrected when encountered by either decreasing the arc voltage
or increasing the amperage. Globular transfer can take place with any
electrode diameter.
Basic flux-cored wires tend to operate in a globular mode or in a
globular-spray transfer mode where larger than normal spray droplets
are propelled across the arc, but they never achieve a true spray
transfer mode. This transfer mode is sometimes referred to as non-axial
globular transfer.
Self-shielded flux-cored wires operate in a predominantly globular
transfer mode although at high currents the wire often ‘explodes’ across
the arc.
Spray Transfer
In spray transfer, metal is projected by an electromagnetic force from
the wire tip in the form of a continuous stream of discrete droplets
approximately the same size as the wire diameter. High deposition
rates are possible and weld appearance and reliability are good. Most
metals can be welded, but the technique is limited generally to plate
thicknesses greater than 6mm. Spray transfer, due to the tendency of
the large weld pool to spill over, cannot normally be used for positional
welding. The main exception is aluminium and its alloys where, primarily
because of its low density and high thermal conductivity, spray transfer
in position can be carried out.
The current flows continuously because of the high voltage maintaining a
long arc and short-circuiting cannot take place. It occurs best with argonbased gases.
In solid wire MIG/MAG, as the current is increased, dip transfer passes
into spray transfer via a transitional globular transfer mode. With metalcored wires there is virtually a direct transition from dip transfer to spray
transfer as the current is increased.
For meta-cored wire spray transfer occurs as the current density
increases and an arc is formed at the end of the filler wire, producing
a stream of small metal droplets. Often the outside sheath of the wire
will melt first and the powder in the centre flows as a stream of smaller
droplets into the weld pool. This effect seems to give much better
transfer of alloying elements into the weld.
In spray transfer, as the current density increases, an arc is formed at the
end of the filler wire, producing a stream of small metal droplets. In solid
wire MIG/MAG this transfer mode occurs at higher currents. Flux-cored
wires do not achieve a completely true spray transfer mode but a transfer
mode that is almost true spray may occur at higher currents and can
occur at relatively low currents depending on the composition of the flux.
Rutile flux-cored wires will operate in this almost-spray transfer mode, at
all practicable current levels. They are also able to operate in this mode
for positional welding too. Basic flux-cored and self-shielded flux-cored
wires do not operate in anything approaching true spray transfer mode.
BOC Smootharc MIG 180 Operating manual
Typical Metal Transfer Mode
Metal Inert Gas (MIG)
Metal Active Gas (MAG)
Flux Cored (Gas Shielded)
Flux Cored (Self Shielded)
Metal Cored
Spray Transfer
* Not True Spray
Pulsed Transfer
Pulsed arc welding is a controlled method of spray transfer, using
currents lower than those possible with the spray transfer technique,
thereby extending the applications of MIG/MAG welding into the range
of material thickness where dip transfer is not entirely suitable.The
pulsed arc equipment effectively combines two power sources into one
integrated unit. One side of the power source supplies a background
current which keeps the tip of the wire molten. The other side produces
pulses of a higher current that detach and accelerate the droplets of
metal into the weld pool. The transfer frequency of these droplets is
regulated primarily by the relationship between the two currents. Pulsed
arc welding occurs between ±50-220A, 23–35 arc volts and only with
argon and argon-based gases. It enables welding to be carried out in all
2.5Fundamentals of MIG/MAG, FCAW and MCAW
Welding Technique
Successful welding depends on the following factors:
1 Selection of correct consumables
2 Selection of the correct power source
3 Selection of the correct polarity on the power source
4 Selection of the correct shielding gas
5 Selection of the correct application techniques
a Correct angle of electrode to work
b Correct electrical stickout
c Correct travel speed
6 Selection of the welding preparation
Selection of Correct Consumable
Chemical composition
As a general rule the selection of a wire is straight forward, in that
it is only a matter of selecting an electrode of similar composition to
the parent material. It will be found, however, that there are certain
applications that electrodes will be selected on the basis of its
mechanical properties or level of residual hydrogen in the weldmetal.
Solid MIG/MAG wires are all considered to be of the 'low Hydrogen type'
The following table gives a general overview of the selection of some of
the BOC range of MIG/MAG wires for the most common materials.
BOC Smootharc MIG 180 Operating manual
Cast and Helix
Cast – Diameter of the circle
Helix – Vertical height
Common Materials Welded with BOC MIG Wire
AS2074 C1,C2,C3,C4-1,C4-2,C5,C6
AS/NZS1163 C250
AS/NZS3678 200,250,300
ASTM A36,A106
Stainless Steel
Grade 304/L
Grade 309
Grade 316/L
BOC Mild Steel MIG Wire
BOC Mild Steel MIG Wire
BOC Mild Steel MIG Wire
BOC Mild Steel MIG Wire
BOC Stainless Steel 308LSi
BOC Stainless Steel 309LSi
BOC Stainless Steel 316LSi
Physical condition
Surface condition
The welding wire must be free from any surface contamination including
mechanical damage such as scratch marks.
A simple test for checking the surface condition is to run the wire through
a cloth that has been dampened with acetone for 20 secs. If a black
residue is found on the cloth the surface of the wire is not properly
Cast and Helix
The cast and helix of the wire has a major influence on the feedability of
MIG/MAG wire.
If the cast is too large the wire will move in an upward direction from the
tip when welding and if too small the wire will dip down from the tip. The
result of this is excessive tip wear and increased wear in the liners.
If the helix is too large the wire will leave the tip with a corkscrew effect.
Selection of the Correct Power Source
Power sources for MIG/MAG welding is selected on a number of different
criteria, including:
1 Maximum output of the machine
2 Duty cycle
3 Output control (voltage selection, wire feed speed control)
4 Portability
The following table gives an indication of the operating amperage for
different size wires.
Wire Size
0.8 mm
0.9 mm
1.0 mm
1.2 mm
Amperage Range (A)
S election of the Correct Polarity on the Power Source
Many power sources are fitted with an optional reverse polarity dinse
To achieve the optimum welding it is important to adhere to the
consumable manufacturer's instruction to select the polarity.
As a general rule all solid and metal cored wires are welded on electrode
positive. (Work return lead fitted to the negative connector.)
Some grades of self-shielded flux-cored wires (i.e. E71T-11, E71T-GS etc)
needs to be welded on electrode negative. (Work return lead fitted to the
positive connector.)
BOC Smootharc MIG 180 Operating manual
Selection of the Correct Shielding Gas
The selection of the shielding gas has a direct influence on the
appearance and quality of the weldbead.
The thickness of the material to be welded will determine the type of
shielding gas that has to be selected. As a general rule the thicker the
material (C-Mn and Alloy steels) are the higher the percentage of CO2 in
the shielding gas mixture.
Different grades of shielding are required for materials such as stainless
steel, aluminium and copper.
The following table gives an indication of the most common shielding
gases used for Carbon Manganese and alloy steel.
Material thickness
1–8 mm
5–12 mm
>12 mm
Recommended shielding gas
Argoshield Light
Argoshield Universal
Argoshield Heavy
More detailed selection charts, including recommendations for welding
parameters (voltage, amperage, electrical stickout, travel speed and
gas flow rate) can be found in the following pages.
2.6 4T/2T Trigger Latch Selection
On all MIG machines there is no current or wire feed until the trigger on
the torch is depressed. If a welder is doing a lot of welding then he has to
hold the trigger down for long periods of time and may cause discomfort.
This is can be similar to repetitive strain injury (RSI) that has become a
very popular topic for compensation by office workers.
On all machines a special function called 2T and 4T is available. Also
referred to as trigger latching, this special feature allows the operator to
relax the trigger after first depressing it, the gas shielding to start before
the welding commences. This feature is of particular importance as it
ensures that the weld will have adequate gas shielding to eliminate the
risk of oxidisation (contaminants) causing a defective weld. (Remember,
a defective weld may not be detected by a visual inspection.)
The 2T/4T function also allows for the shielding gas to continue after the
weld has finished and cooled. This eliminates the risk of oxidation while
the weld is still in its molten state. This is particularly important when
welding stainless steel materials.
BOC Smootharc MIG 180 Operating manual
3.0 General Welding Information
3.1 Recommended Welding Parameters for MIG/MAG
Argoshield Light
Welding Parameters
Dip Transfer
Material thickness (mm)
Welding position
Horizontal /
Horizontal /
Horizontal /
Horizontal /
Wire diameter (mm)
Current (amps)
Voltage (volts)
Wire feed speed (m/min)
Gas rate flow (L/min)
Travel speed (mm/min)
Stainshield (Aus) or Stainshield Light (NZ)
Welding Parameters
Dip Transfer
Material thickness (mm)
Welding position
Horizontal /
Horizontal /
Horizontal /
Wire diameter (mm)
Current (amps)
Voltage (volts)
Wire feed speed (m/min)
Gas rate flow (L/min)
Travel speed (mm/min)
BOC Smootharc MIG 180 Operating manual
4.0 Correct Application Techniques
Electrical stickout
Contact Tube Setback
Standoff Distance
Visible Stickout
Arc length
Electrical Stickout
Gas Nozzle
Contact Tube
Correct Application Techniques
Direction of welding.
MIG/MAG welding with solid wires takes place normally with a push
technique. The welding torch is tilted at an angle of 10° towards the
direction of welding. (Push technique)
Flux cored welding with cored wires takes place normally with the drag
technique. The welding torch is tilted at an angle of 10° away from the
direction of welding. For all other applications the torch angle remains
the same.
The influence of changing the torch angle and the welding direction on
the weld bead profile can be seen below.
Torch position for butt welds
Torch perpendicular to workpiece narrow bead width with increased
When welding butt welds the torch should be positioned within the
centre of the groove and tilted at an angle of ±15° from the vertical
plane. Welding is still performed in the push technique.
Torch positioned at a drag angle of 10° narrow bead with excessive
BOC Smootharc MIG 180 Operating manual
Electrical stickout
Travel speed
Torch position for fillet welds
When welding fillet welds the torch should be positioned at an angle of
45° from the bottom plate with the wire pointing into the fillet corner.
Welding is still performed in the push technique.
Electrical stickout
The electrical stickout is the distance between the end of the contact
tip and the end of the wire. An increase in the electrical stickout results
in an increase in the electrical resistance. The resultant increase in
temperature has a positive influence in the melt-off rate of the wire that
will have an influence on the weldbead profile.
Influence of the change in electrical stickout length on the weldbead
The travel speed will have an influence on the weldbead profile and the
reinforcement height.
If the travel speed is too slow a wide weldbead with excessive rollover
will result. Contrary if the travel speed is too high a narrow weldbead
with excessive reinforcement will result.
BOC Smootharc MIG 180 Operating manual
5.0 Package Contents
Package consists of the following:
• Power source
• Work return lead
• Binzel MB15AK MIG/MAG torch
• Regulator
• Gas hose
• Spare feed rolls
• Operating manual
BOC Smootharc MIG 180 Operating manual
6.0 Smootharc MIG 180 Installation
Installation for MIG/MAG process
6.1 Installation for MIG/MAG process
1 Connect the gas cylinder to the regulator. Select correct shielding gas
for the application.
2 Insert the earth return lead connection into the front panel.
3 Fit the wire spool to the machine. Select correct welding wire for
4 Select the appropriate feed roller to suit the wire being used
-- This machine comes complete with two types of wire feed rollers
-- V groove for use with solid carbon manganese and stainless steels
-- U groove for use with soft wires such as aluminium
5 Loosen the wire feed tension screws and insert the wire. Re fit and
tension rollers ensuring the wire is gripped sufficiently so as not to
slip but avoid over tightening as this can affect feed quality and cause
wire feed components to wear rapidly.
6 Fit and tighten the torch on the output connection [A]. Ensure correct
torch liner and contact tip are selected.
7 Select the correct polarity for the type of wire used as indicated on
the consumable packaging. This is achieved by swapping the polarity
terminal wires. For most solid wires the terminal should be set as
torch positive.
8 For torch positive, plug the short mechanical connector (link plug) [B]
on the front panel into the positive (+) terminal and the work return
lead [C] into the negative (-) terminal.
9 For torch negative, couple the short mechanical connector [B] into the
terminal marked negative (-), and the work return lead [C] into the
positive (+) terminal.
BOC Smootharc MIG 180 Operating manual
7.0 Control panel
Front Panel of MIG 180
Multifunctional data display
Wire Inch
2T / 4T switch
Data selection
Multifunctional data adjustment
Multifunctional data adjustment
Coarse adjustments made by pressing and turning the knob.
Fine adjustments made by only turning the knob.
7.1 Polarity selection
The polarity on this machine can be reversed if so required for certain
types of self-shielded wires. This can be achieved by switching the work
return lead from the negative (-) to the positive (+) dinse socket.
BOC Smootharc MIG 180 Operating manual
8.0Smootharc MIG 180 Operation
Illustration 1. Start-up display
8.1 Starting up
Switch on the welding power source. The front panel display will light up
as shown in Illustration 1. After the Multifunctional Data display (or any
key or knob on front panel) flashes for 5 seconds, the machine enters
into the welding mode that was saved in the last shutdown.
BOC Smootharc MIG 180 Operating manual
Illustration 2. Preset voltage
8.2 Operation instruction
The wire can be fed through the system by pressing the
Wire Inch button.
To feed the wire through the torch the Wire Inch button has to be
pressed to feed the wire. To stop feeding the wire release the button.
In both illustrations shown above the Multifunctional Data display shows
a preset voltage of 19.5V and a wire feed speed of 05.0m per minute.
The welding mode (2T/4T) can be selected by depressing the 2T/4T.
The selected mode will illuminate. (Refer to the section on MIG
Fundaments on page 15 of this manual for an explanation of 2T and 4T
The welding parameters can be adjusted during welding by turning the
Multifunctional Data adjustment. This action will synergically change
both parameters (volts and wire feed speed).
The synergic welding parameter range is 17.5V 2.0 m/min to
25.8V 12 m/min.
Illustration 3. Wire Check
BOC Smootharc MIG 180 Operating manual
Illustration 4. Fine adjustment of voltage range
Data selection
Pressing the Data Selection button will enable you to switch between:
1 Arc welding adjustment mode
2 Inductance
3 Preset voltage and wire speed
By pressing the Data Selection button the Multifunctional Data display
will change according to the welding parameter function mode that
can be changed. In Illustration 4, it displays the arc voltage and the
adjustment that can be done. In this mode the arc voltage is adjustable
and the adjustment range of the preset value is ±20%.
When the Data Selection button is pressed again the Multifunctional
Data Display will change to display the inductance as shown in
Illustration 5. In this mode the inductance is adjustable and its
adjustment range is ±10%.
When the Data Selection key is pressed again the Multifunctional Data
Display will return to the preset voltage and wire feed speed.
If settings are unchanged for three seconds the Multifunctional Data
Display will flash once to indicate that the setting has been saved and
these will be retained, and displayed when the machine restarts.
Illustration 5. Fine adjustment of Inductance presetting range
BOC Smootharc MIG 180 Operating manual
9.0 Troubleshooting and Fault Finding
9.1 MIG/MAG functions
Power source
Primary cable
Earth cable and clamp
Connectors and lugs
Fault symptom
No or low welding output
Arc will not initiate
Overheating of connectors and lugs
Erratic or no output control
Poor or incorrect primary connection, lost phase
Damaged, loose or undersized cables and clamps
Loose or poorly crimped connectors
Switches damaged or incorrectly set for the application
Gas solenoid valve
Wire feed rolls
Fault symptom
No gas flow or gas flows continuously
Wire slippage, wire deformation
Inlet, outlet guides
Torch connector
Wire shaving or snarling
Wire restriction, gas leaks, no trigger control
Wire feed speed control
No control over wire feed speed, no amperage
Wire live when feeding through cable and torch
before welding
Wire spool drags or overruns
Gas valve faulty or sticking in open position
Incorrect feed roll size, incorrect tension adjustment,
Incorrect wire guide sizes, misalignment
Torch connector not correctly mounted or secured, incorrect size
of internal guide, bent contact pins
Faulty wire speed feed potentiometer, machine in overload or
trip condition
Faulty wire inch switch, activitation of torch trigger switch
Wire feeder
Wire inch switch
Spindle brake set too tight or too loose, spool not properly
located on spindle
Welding torch
Fault symptom
Welding torch overheats
Erratic wire feed, wire snarls up at outlet guide
Gas distributor
Contact tip
Inadequate gas flow, contaminated or porous weld
Inadequate gas cover, restricted joint accessibility
Erratic feeding, wire shudder, wire burnback,
unstable arc, spatter
Arcing between contact tip and nozzle and
between nozzle and workpiece
Welding torch underrated for welding application
Liner of incorrect type and size for wire in use, worn or dirty
liner, liner too long or too short
Damaged or blocked distributor
Nozzle too large or too small, incorrect length or shape
Incorrect size of contact tip, incorrect contact tip to nozzle
distance for metal transfer mode, tip has worn out
No nozzle insulator fitted, spatter build up has caused parts to
short out
Fault symptom
No gas flow, gas leaks at regulator body or
cylinder valve
Leaks at connections or in the hose, porosity in
the weld
Blocked inlet stem, leaking inlet stem to body thread, bullnose
not properly seated in cylinder valve
Poorly fitted loose connections, damaged hose, air drawn into
gas stream
Fault symptom
Erratic wire feeding or wire stoppages
Wire sticks in contact tip, erratic feeding
Weld has excessive amount of spatter
Damaged wire basket, loose spooling, random-wound wire
Varying wire diameter, copper flaking, surface damage
Wrong polarity has been selected
Nozzle insulator
Regulator / flowmeter
Inlet stem
Gas hose and fitting
Welding wire
Wire basket and spool
BOC Smootharc MIG 180 Operating manual
Porosity in Weld Deposit
Entrapped impurities, hydrogen, air, nitrogen, water vapour
Defective gas hose or loose connection
Filler material is damp (particularly aluminium)
Filler material is oily or dusty
Alloy impurities in the base metal such as sulphur,
phosphorous, lead and zinc
Excessive travel speed with rapid freezing of weld trapping
gases before they escape
Contaminated shield gas
Do not weld on wet material.
Check hoses and connections for leaks
Dry filler metal in oven prior to welding
Replace filler metal
Change to a different alloy composition which is weldable. These impurities can cause a
tendency to crack when hot
Lower travel speed
Replace the shielding gas
Inadequate shielding
Gas flow blockage or leak in hoses or torch
Excessive travel speed exposes molten weld to
atmospheric contamination
Wind or drafts
Excessive electrode stickout
Excessive turbulence in gas stream
Locate and eliminate the blockage or leak
Use slower travel speed or carefully increase the flow rate to a safe level without creating
excessive turbulence. Use a trailing shield cup
Set up screens around the weld area
Reduce electrode stickout. Use a larger size nozzle
Change to gas saver parts or gas lens, lower flow rate if possible
BOC Smootharc MIG 180 Operating manual
10.0 Periodic Maintenance
Only authorised electricians should carry out repairs and internal
Modification of the 15A primary input plug or fitment of a lower rated
primary input plug will render the warranty null and void.
The working environment or amount of use the machine receives should
be taken into consideration when planning maintenance frequency of
your Smootharc welder.
Preventative maintenance will ensure trouble-free welding and increase
the life of the machine and its consumables.
10.1 Power Source
• Check electrical connections of unit at least twice a year.
• Clean oxidised connections and tighten.
• Inner parts of machine should be cleaned
with a vacuum cleaner and soft brush.
• Do not use any pressure-washing devices.
• Do not use compressed air as pressure may pack dirt even more tightly
into components.
BOC Smootharc MIG 180 Operating manual
11.0 Technical Specifications
MIG 180
Part No.
Power voltage
Rated input plug
Single phase 240 V ±15 %
50/60 Hz
15 A
Output current
Rated working voltage
No-load voltage
Duty cycle
Wire feeder
Wire feeder speed
Welding wire diameter
Remote control
Power factor
Insulation grade
Housing protection grade
Welding thickness (mm)
Dimensions L × W × H
50 to 175 A
16.5 to 22.8 V
56 V
35 %
2 to 12 m/min
0.6/0.8/1.0 mm
80 %
>0.8 mm
420 × 220 × 439 mm
12.8 kg
IEC 60974.1
BOC Smootharc MIG 180 Operating manual
12.0 Warranty Information
12.1 Terms of Warranty
12.3 Warranty Period
The Smootharc machine has a limited warranty that covers manufacturing
and material defects only. The warranty is affected on the day of
purchase and does not cover any freight, packaging and insurance costs.
Verbal promises that do not comply with terms of warranty are not
binding on warrantor.
The warranty is valid for 18 months from date of purchase provided the
machine is used within the published specification limits.
12.2 Limitations on Warranty
The following conditions are not covered under terms of warranty: loss or
damage due to or resulting from natural wear and tear, non‑compliance
with operating and maintenance instructions, connection to incorrect
or faulty voltage supply (including voltage surges outside equipment
specs), incorrect gas pressure overloading, transport or storage damage
or fire or damage due to natural causes (e.g. lightning or flood). This
warranty does not cover direct or indirect expenses, loss, damage of
costs including, but not limited to, daily allowances or accommodation
and travelling costs.
Modification of the 15A primary input plug or fitment of a lower rated
primary input plug will render the warranty null and void.
Under the terms of warranty, welding torches and their consumables are
not covered. Direct or indirect damage due to a defective product is not
covered under the warranty. The warranty is void if changes are made
to the product without approval of the manufacturer, or if repairs are
carried out using non-approved spare parts. The warranty is void if a nonauthorised agent carries out repairs.
12.4 Warranty Repairs
A BOC approved service provider must be informed within the warranty
period of any warranty defect. The customer must provide proof of
purchase and serial number of the equipment when making a warranty
claim. Warranty repairs may only be carried out by approved BOC service
providers. Please contact your local BOC Gas & Gear for a directory of BOC
approved service providers in your area.
For more information contact the BOC Customer Service Centre.
BOC Australia
131 262
[email protected]
BOC Limited
10 Julius Avenue, North Ryde NSW 2113, Australia
970–988 Great South Road, Penrose, Auckland, New Zealand
© BOC Limited 2013. BOC is a trading name of BOC Limited, a Member of The Linde Group. Reproduction without permission is strictly prohibited. Details given in this document are
believed to be correct at the time of printing. Whilst proper care has been taken in the preparation, no liability for injury or damage resulting from its improper use can be accepted.
MP12-0759 . FDAUS . 1213
BOC New Zealand
0800 111 333
[email protected]
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