L254
Health & Safety Maintenance: D&T Workshop Equipment
L254 June 2006
Health & Safety
Maintenance of
D&T Workshop
Equipment
L254
June 2006
Strictly Confidential
Circulate to members and associates only
As with all CLEAPSS materials, members and associates are free to copy all or part of
this guide for use in their own establishments.
© CLEAPSS® 2006
CLEAPSS
Brunel University
Uxbridge
UB8 3PH
Tel: 01895 251496
Fax: 01895 814372
E-mail: [email protected]
Web site: www.cleapss.org.uk
Contents
1
2
3
4
5
The scope of this guide
1
1.1
Introduction
1
1.2
Risk assessments
2
1.3
Maintenance of the learning environment
2
1.4
Maintenance of hand tools and equipment
2
1.5
Maintenance of machines
3
General principles of maintenance
3
2.1
Cleaning
3
2.2
Local exhaust ventilation systems
4
2.3
Electrical and gas installations
4
2.4
Lubrication
5
Detailed maintenance advice on workshop machines
5
3.1
Disc and belt sanding machines
5
3.2
Drilling machine
6
3.3
Bench-mounted jig saw
6
3.4
Band saw
7
3.5
Circular saw
7
3.6
Planing machines for wood
8
3.7
Radial arm saw
8
3.8
Wood-turning lathe
9
3.9
Metal-turning lathe
9
3.10
Milling machine - horizontal/vertical
9
3.11
Power hacksaw
10
3.12
Mortising machine
10
3.13
Double-ended, high-speed grinding machine
11
3.14
Polishing/buffing machine
11
Detailed maintenance advice on metal-heating equipment
11
4.1
Gas safety system
11
4.2
Brazing hearth and/or chip forge
12
4.3
Crucible furnace
12
Guide to cutting speeds
12
5.1
Drilling
13
5.2
Wood-turning lathe
13
5.3
Metal-turning lathe
13
5.4
Milling machine
13
Equipment register and maintenance log
15
Appendix:
Guide L254
Health & Safety Maintenance
of D&T Workshop Equipment
1
The scope of this guide
These notes have been prepared to give an overview of the way in which maintenance
of equipment will contribute to healthy and safe working conditions in design &
technology (D&T), particularly in school workshops. The main focus is on resistant
materials.
It should be read in conjunction with other CLEAPSS publications, particularly the
following.
• Model Risk Assessments for D&T in Secondary Schools and Colleges.
• Guide L225, Local Exhaust Ventilation in D&T.
• Leaflet PS62, LEV in D&T: Suppliers, Testers and Monitoring Equipment.
These, and other CLEAPSS publications relevant to D&T, will be found on the
CLEAPSS D&T Publications CD-ROM, which should be in all relevant member schools.
Any updates to publications on the CD-ROM, or any new publications, will be found
on the members’ part of the CLEAPSS web site: www.cleapss.org.uk. If you are unsure
of your user name and password, please phone the CLEAPSS Helpline 01895 251496 or
e-mail: [email protected], making it clear you want access to the D&T area of
the members-only web site and giving details of your school’s name and address.
1.1
Introduction
All equipment used in design & technology will require some sort of maintenance
programme. This will range from ensuring that hand tools are maintained with sharp
cutting edges to ensuring that machine tools are correctly lubricated and are maintained in good order. It should be remembered that a blunt cutting tool is more dangerous than a sharp one, since more force is required to make it cut. This applies to both
hand and machine tools. Cleaning of machines and equipment is an important part of a
maintenance programme, since equipment that is clogged with dirt or dust is unlikely
to work in an efficient manner.
A regular maintenance programme should be established which should aim for preventative maintenance rather than emergencies. The frequency of maintenance will
obviously depend on the amount of use of the equipment and the nature of the hazards
and risks. It is a good idea to have a check sheet for equipment and a planned
programme of checks. A sample of a possible check sheet is given in Appendix 1 and it
is available on the members’ part of the CLEAPSS web site in an easily-modified
electronic file, DL254; see above for access. The checklists in sections 3 and 4 are also
included in this download file. Where technicians are available, they are the obvious
people to do the maintenance checks but anyone who does such work should be
trained to do it properly.
1
1.2
Risk assessments
Before maintenance of fixed equipment is begun, the hazards of doing it must have
been identified and the risks assessed and controlled. It is clearly sensible to keep the
written assessment until it is next needed. Whilst a visual inspection of the condition of
electrical cables and the supply to fixed equipment such as workshop machines can be
done by anyone, on no account should unqualified people carry out electrical maintenance. Maintenance of gas equipment should also be carried out only by a qualified
person. If it is necessary to remove covers or guards from machines and other equipment, to permit maintenance or repair work, then the equipment should be isolated
from the power supply through the use of isolating switches or by unplugging from the
socket outlet. Where possible, isolators should be locked in the ‘OFF’ position. Notices
should be placed on equipment to state that it is under repair and must not be used.
Where possible, cutting tools that have sharp edges should be removed before repairs
or maintenance are carried out. Where maintenance is required, but cannot be done at
once, equipment should be taken out of use until such time as the necessary work can
be carried out and a notice fixed to the machine to state that it must not be used.
1.3
Maintenance of the learning environment
The condition of the learning environment is an important aspect of maintenance.
Teaching, preparation and store rooms should be kept in a clean and tidy condition.
Where necessary, the daily cleaning schedule should be modified to allow sufficient
time for proper cleaning to take place. Removal of wood dust is best done with a suitable industrial vacuum cleaner1 rather than by brushing. All waste materials should be
removed at the end of the school day.
Consumable materials, such as timber, should be properly stored in suitable racks and
should not obstruct doorways, fire exits, fire-fighting equipment, emergency-stop buttons or machines. The same is true about large items of pupils’ work.
Fire extinguishers should be hung on the correct type of bracket and should not be used
for propping open doors. They will normally be checked by a competent person on a
regular basis and the check should be recorded on the equipment itself. If this is not
happening, the head of department should inform the employer2.
Eye protection should be cleaned regularly. It is best if eye protection is kept in a
suitable holder3 located next to the machine with which it is to be used.
1.4
Maintenance of hand tools and equipment
Cutting tools with sharp edges should be maintained in good condition.
The frequency of sharpening will depend on the amount of use and the material being
cut. It is obvious that tools need to be sharpened when they are blunt. This means that a
1
A vacuum cleaner designed to collect wood dust must be used. General-purpose vacuum cleaners are unlikely to be
suitable, as they will not trap the fine dust involved. See the CLEAPSS leaflet PS62, LEV in D&T: Suppliers, Testers and
Monitoring Equipment for companies that supply suitable models. This leaflet is updated as necessary. Check the latest
version on the members’ part of the CLEAPSS web site.
2
The employer for most maintained schools (strictly, community and voluntary-controlled schools) is the local authority. For
foundation & voluntary-aided schools, academies, post-16 colleges and most independent schools, it is the governing body.
3
For example, in a self-sealing plastic bag, attached by Velcro to the wall. The bag should be labelled with the eye protection
symbol. A graphic of such a symbol should be available in the science department, on the CLEAPSS Science Publications
CD-ROM. We hope to make it available on a future edition of the CLEAPSS D&T Publications CD-ROM.
2
planned programme of sharpening them every day, every week or every month may
not be adequate.
Paper for example, blunts scissors and craft knives very easily and it is better to use the
type of craft knife with replaceable blades, rather than attempting to sharpen them.
Woodworking with blunt tools causes a particular problem since pupils, who may well
be inexperienced and physically small, will need to exert excessive effort to cut timber.
This then presents an additional hazard because they are unable to control the force
needed. Chisels and the blades of planes may need sharpening every week, depending
on the amount of use.
Teachers who have a detailed knowledge of woodworking will know that some types
of timber wear down sharp-edged tools very quickly and sharpening may be needed
much more frequently than once each week. Depending on the amount of use, saws
used to cut timber will typically need sharpening once a year. These days, it is often
cheaper to buy new bench saws than to have the old ones sharpened, especially in parts
of the country where it is difficult to find companies with the expertise to carry out
sharpening. Proper storage of tools with sharp edges will help to maintain the sharp
edge. Planes should be stored so that the blade is not touching a surface; they should be
laid on their side on the work bench when not in use. Wood chisels should be stored in
proper racks with the cutting edges protected, as should craft knives. Handles of files
need to be checked for splits, and for tightness of fit onto the tang of the file. The
hammered end of tools such as centre punches and cold chisels will occasionally need
grinding to remove burrs.
1.5
Maintenance of machines
The amount of machine maintenance will depend on the type of machine and the way
in which it is designed. Many schools still use older machines of heavy cast-iron
construction. These machines were often designed for industrial use and are normally
very robust. Whilst sometimes dated in appearance, they will normally last a long time
in school use. In contrast, modern machines are frequently constructed from steel
pressed into shape and are not nearly as robust as the older models. Some schools
purchase machines designed for the d-i-y market. These types of machines are designed
for infrequent d-i-y use, rather than the more-frequent use which would be the norm in
schools and are unlikely to give long service. Their purchase may prove to be a false
economy.
2
General principles of maintenance
2.1
Cleaning
All machines should be cleaned regularly, although the frequency of cleaning will
depend on the amount of use. This will range from the normal cleaning to remove
sawdust, chips or swarf after use, to a more-thorough cleaning each week. Woodworking machines such as band saws, circular saws and planing machines should be
checked to see that dust and chips are being removed by the dust-extraction system.
Some types of band saw have the collection point for dust located in a poor position
and dust is often not removed effectively from all crevices. In these cases, an industrial
vacuum cleaner specifically designed to collect dust should be used to remove it during
general maintenance.
3
2.2
Local exhaust ventilation systems4
The filters of dust-extraction systems should be cleaned at frequent intervals, at least
weekly, to remove the dust and the collection bags or trays emptied frequently. Note
that appropriate dust masks should be worn during emptying. (Type FFP2 is suitable
for ordinary saw dust but type FFP3 should be used if there is a lot of fine dust, eg,
from MDF.) Wood dust should be disposed of in sealed bags and not tipped loosely
into a dustbin. The ducting of dust-extraction systems needs checking to ensure that
slivers or chips of wood are not obstructing it, especially on bends. This can impede the
air flow and reduce the efficiency of the system. Note that the COSHH Regulations
require local exhaust systems to be examined at least every 14 months and a record
maintained of the efficiency of the system. A notice should be fixed to each extraction
unit to indicate that it has been checked on a particular date.
2.3
Electrical and gas installations
The condition of electrical cables, fixed and flexible conduit should be visually checked.
The operation of all switches (including isolating, no-volt release and overload
switches) should be checked. The operation of emergency-stop buttons in workshops
should be checked once every half term. Flexible conduit in particular needs checking
to make sure that there are sound connections at each end. Isolators need to be checked
by the operation of the lever to ensure that they do in fact cut off the power to the
machine and that the lever moves easily. Checking that an isolator breaks all power
connections to the machine (ie, line and neutral or all three phases and neutral) is best
left to a person competent to do it. (This is unlikely to be a member of the school staff.)
Care should be taken to ensure that access to isolators is not impeded by machines,
furniture or materials. The operation of residual-current devices (earth-leakage circuit
breakers) should be checked by the use of the test button on the device.
Portable electrical equipment needs to be checked as required by the Electricity at Work
Regulations. It is for the employer to decide who does the checking. Sometimes, a
contractor may go round from school to school. Elsewhere the task may be delegated to
the school which in turn may employ a contractor or use its own, suitably-trained, staff.
The time interval for testing is not directly specified but most employers expect most
equipment to be checked annually. However, equipment subject to arduous or heavy
use, such as power tools and extension leads, should be inspected more frequently.
Items that are rarely unplugged, eg, refrigerators, may only need checking every 3 or 4
years. The operation of electrical interlocks on machine guards should be checked to
ensure that they function correctly.
Guidance from the HSE5 on the Electricity at Work Regulations suggests that fixed electrical installations should be inspected at least every 5 years, although this is normally
arranged by the employer. There is a similar requirement for the inspection of gas
installations6. However, heads of department should check that this is happening and,
4
For more details, see the CLEAPSS guide L225, Local Exhaust Ventilation in Design and Technology, available on the
CLEAPSS D&T Publications CD-ROM.
5
Guidance Note GS23, Electrical safety in schools, HSE, 1990. Although this is now out of print, the HSE has informed
CLEAPSS that it regards most of the advice as still valid.
6
IM/25 Guidance Notes on Gas Safety in Educational Establishments, British Gas/DES, 1989, paragraph 2 stated that
checking of the soundness of gas supply pipework should not normally be needed more often than once every five years.
However, its replacement IGE/UP/11 Gas installations for educational establishments, IIGEM, 2004, offers more
complicated advice.
4
if not, should take steps to ensure that the employer is informed. The contractor carrying out such tests should apply labels to the equipment to indicate when testing has
been done. There will also be records made but these may go to the employer or be
held by the bursar.
Hoses on gas equipment should be checked for damage before use and replaced where
required.
2.4
Lubrication
Moving parts of machines will require lubrication. Some machine bearings are ‘sealed
for life’ and will not require additional lubrication. For other machines, oil or greasing
of bearings will be required. Lathes with geared headstocks, and some drilling
machines that have a gearbox, will have an oil reservoir that will need checking and refilling as required. The feed drives on planing machines for wood will require checking
and cleaning. Excess dust should be removed and chain drives should be greased.
Machines such as metal-turning lathes, milling machines and power hacksaws will
need the slideways lubricated as necessary.
It is good practice to apply a coat of a thin lubrication oil (eg, as used in motor cars) to
bright metal parts of tools and machines at the start of holiday periods, especially
where there is likely to be excessive moisture in the air.
3
Detailed maintenance advice on workshop machines
3.1
Disc and belt sanding machines
Daily check
• Clean any dust not removed by the extraction system.
• Check condition of sanding belt/disc and replace if torn/worn.
• Check fit of sanding table to disc/belt (it should be as close as possible, normally
no greater than 2 mm).
• Check that quadrant guard is in the correct position.
Weekly check
•
•
•
•
Clean filters in dust-extraction system, if fitted.
Empty dust-collection tray/bag if fitted.
Visually check condition of electrical switches, conduit, cable, etc.
Lubricate if necessary.
Termly check
•
•
•
•
Check condition of motor, drive system and drive belts, if fitted. Replace if worn.
Lubricate if necessary.
Check operation of dust-extraction system.
Check bearings for wear.
5
3.2
Drilling machine
Daily check
• Check that the chuck guard is clean, functions correctly and is not cracked/broken.
• Make sure that the guard over the driving belt fits correctly and that the interlock or securing device is in place and working correctly.
Weekly check
•
•
•
•
Make sure that the chuck key fits correctly and is not worn.
Visually check condition of electrical switches, conduit, cable, etc.
Lubricate if necessary.
Make sure that the drill head clamping bolts are tight and the head locking ring
is in place.
• Make sure that the table clamp functions correctly.
• Check condition of drill bits. Sharpen as required. Replace twist drills that have
worn shanks.
• If wooden blocks are used under the work piece, replace those that are worn.
Termly check
• Check condition of motor, drive system and drive belts. Replace if worn.
• Lubricate if necessary. Machines with gears running in an oil bath should have
the oil level checked.
• Check bearings for wear.
• Check that machine vices and hand vices function correctly and are not worn or
clogged with waste materials.
3.3
Bench-mounted jig saw
Daily check
•
•
•
•
Clean any dust not removed by the extraction system.
Check condition of blade and replace if blunt.
Check that blade guard is correctly set.
Where fitted, check that machine ‘foot’ functions correctly.
Weekly check
•
•
•
•
•
Clean filters in dust-extraction system, if fitted.
Empty dust-collection tray/bag, if fitted.
Visually check condition of electrical switches, conduit, cable, etc.
If fitted, check fit of table insert and replace if required.
Lubricate if necessary.
Termly check
•
•
•
•
Check condition of motor, drive system and drive belts, if fitted. Replace if worn.
Lubricate if necessary.
Check operation of dust-extraction system.
Check bearings for wear.
6
3.4
Band saw
Daily check
•
•
•
•
Clean any dust not removed by the extraction system.
Check condition of blade; replace if blunt or if welded joint on blade is suspect.
Check that blade guard is correctly set.
Check that machine braking system functions correctly.
Weekly check
•
•
•
•
Clean filters in dust-extraction system, if fitted.
Empty dust-collection tray/bag, if fitted.
Visually check condition of electrical switches, conduit, cable, etc.
If fitted, check fit of table insert to blade and replace if required; (the gap
between the insert and the blade should be no greater than 4 mm).
• Check blade guides and thrust wheel for wear and adjust/replace as required.
• Check tracking setting and condition of rubber tyres on blade wheels, if fitted.
Replace if required.
• Lubricate if necessary.
Termly check
•
•
•
•
3.5
Check condition of motor, drive system and drive belts, if fitted. Replace if worn.
Lubricate if necessary.
Check operation of dust-extraction system.
Check bearings and blade guards for wear and replace if necessary.
Circular saw
Daily check
• Clean any dust not removed by the extraction system.
• Check condition of blade and replace if blunt.
• Check that top or crown guard is correctly set and connected correctly to the
extraction system, if the latter is fitted.
• Check that machine braking system functions correctly.
Weekly check
•
•
•
•
Clean filters in dust-extraction system, if fitted.
Empty dust-collection tray/bag, if fitted.
Visually check condition of electrical switches, conduit, cable, etc.
Lubricate if necessary.
Termly check
•
•
•
•
•
Check condition of motor, drive system and drive belts, if fitted. Replace if worn.
Lubricate if necessary.
Check operation of dust-extraction system.
Clean the inside of the machine using an industrial vacuum cleaner.
Check fit of table insert, if fitted, and replace if required.
7
• Check bearings and replace if necessary.
• Check condition of crown guard and replace if necessary.
3.6
Planing machines for wood:
overhand planer, thicknesser, combined planer / thicknesser
Daily check
• Clean any dust/shavings not removed by the extraction system.
• Check that all guards are correctly set.
• Check that machine braking system functions correctly.
Weekly check
•
•
•
•
•
Clean filters in dust-extraction system, if fitted.
Empty dust-collection tray/bag, if fitted.
Check condition of blades and replace if blunt.
Visually check condition of electrical switches, conduit, cable, etc.
Lubricate if necessary.
Termly check
•
•
•
•
•
3.7
Check condition of motor, drive system and drive belts. Replace if worn.
Check condition of feed roller drive, clean, overhaul and lubricate as required.
Lubricate if necessary.
Check operation of dust-extraction system.
Check bearings and blade guards for wear and replace if necessary.
Radial arm saw
Daily check
• Clean any dust not removed by the extraction system.
• Check that blade guard and side-protection guards are correctly set and function
as required.
• Check that machine braking system functions correctly.
Weekly check
•
•
•
•
•
•
Clean filters in dust-extraction system, if fitted.
Empty dust-collection tray/bag, if fitted.
Visually check condition of electrical switches, conduit, cable, etc.
Check condition of rear timber support and replace if necessary.
Check condition of blade and replace if blunt.
Lubricate if necessary.
Termly check
• Check condition of motor and drive system.
• Lubricate as necessary.
• Check bearings and blade guards for wear and replace if necessary.
8
3.8
Wood-turning lathe
Daily check
• Clean any dust not removed by the extraction system, where fitted.
• Check functioning of electrical interlock for top guard on headstock, or mechanical fixing as appropriate.
• Check that foot switch or other emergency-stopping device functions correctly.
• Check that mandrel nose guard for unused spindle nose is in place.
Weekly check
• If fitted, check functioning of dust-extraction system.
• Visually check condition of electrical switches, conduit, cable, etc.
Termly check
•
•
•
•
3.9
Check condition of motor, drive system and drive belts. Replace if worn.
Lubricate as necessary.
Check operation of dust-extraction system.
Check bearings wear and replace if necessary.
Metal-turning lathe
Daily check
•
•
•
•
Clean chuck guard and any chip screens if fitted.
Check functioning of electrical interlock on chuck guard.
Check that cover plate on outer end of hollow mandrel is in place.
Check functioning of electrical interlock on change wheel guard.
Weekly check
• Visually check condition of electrical switches, conduit, cable, etc.
• Lubricate if necessary.
Termly check
•
•
•
•
•
Check condition of motor, drive system and drive belts. Replace if worn.
Lubricate as necessary, including slideways.
On machines with geared headstock, check oil level in gearbox.
Check bearings for wear and replace if necessary.
If fitted, check coolant pump and system; clean if required.
Yearly check
• If a coolant pump is fitted, drain the coolant, flush out the system with clean
water and replace the coolant every 12 months.
3.10
Milling machine - horizontal/vertical
Daily check
• Clean all cutter guards.
• Check sharpness of milling cutters; take out of use any that are blunt or damaged.
9
Weekly check
• Visually check condition of electrical switches, conduit, cable, etc. This should
include any separate motors used for power feeds.
• Lubricate if necessary.
Termly check
•
•
•
•
Check condition of motor, drive system and drive belts. Replace if worn.
Lubricate as necessary, including slideways.
Check bearings for wear and replace if necessary.
If fitted, check coolant pump and system.
Yearly check
• If a coolant pump is fitted, drain the coolant, flush out the system with clean
water and replace the coolant every 12 months.
3.11
Power hacksaw
Daily check
• Check condition of blade and replace if blunt, or damaged.
• Check that machine functions correctly.
Weekly check
• Clean machine of swarf/metal dust.
• Visually check condition of electrical switches, conduit, cable, etc.
• Lubricate if necessary.
Termly check
•
•
•
•
•
Check condition of motor, drive system and drive belts, if fitted. Replace if worn.
Lubricate as necessary, especially sliders of saw arm.
Check bearings for wear and replace if necessary.
Check functioning of dash pot and pressure-relief system.
If fitted, check coolant pump and system.
Yearly check
• If a coolant pump is fitted, drain the coolant, flush out the system with clean
water and replace the coolant every 12 months.
3.12
Mortising machine
In most schools this machine is used infrequently. Therefore, the checks below should
be made before use, rather than on a regular basis.
Before use
•
•
•
•
•
Check condition of chisel and auger bit; replace or sharpen if blunt or damaged.
Check that the vice functions correctly.
Check that all guards are in place, including the guard around the auger chuck.
Visually check condition of electrical switches, conduit, cable, etc.
Lubricate if necessary.
10
Termly check
• Check condition of motor, drive system and drive belts, if fitted. Replace if worn.
• Lubricate as necessary, especially sliders of motor frame.
• Check bearings for wear and replace if necessary.
3.13
Double-ended, high-speed grinding machine
Weekly check
• Clean eye screens and check that they are in the correct position.
• Check position of tool rest and adjust if required; (the tool rest should be as close
as possible to the grinding wheel, normally within 3 mm).
• Check condition of grinding wheels.
• Visually check condition of electrical switches, conduit, cable, etc.
3.14
Polishing/buffing machine
Weekly check
• Check position of spindle guards and adjust if required.
• Check condition of polishing mops.
• Visually check condition of electrical switches, conduit, cable, etc.
4
Detailed maintenance advice on metal-heating equipment
4.1
Gas safety system
Most school workshops that have several items of heat-treatment equipment will have
a gas safety system which will not allow gas to flow through the system if a leak or
other fault is detected, and which will stop the flow of gas if the electrical power is
stopped, for example, if an emergency-stop button is operated. Where there is only one
item of equipment, then the safety system is often built into the equipment itself.
The gas installation should be checked by a qualified gas engineer (ie, CORGI-registered) every 5 years. A record of the check should be kept.
The functioning of the gas safety system itself can be checked by normal operation.
Normally a warning light will indicate the presence of a fault. Any faults should be
rectified by a qualified, CORGI-registered gas engineer. The system and equipment
connected to it should not be used until any faults have been corrected.
A gas shut-off valve should be installed in every room where there is a gas supply. This
should be located in an accessible position and should be labelled. It should be
standard practice to turn off the gas supply at the end of the school day, or earlier if the
room is not used in the last period of the day. This leaves the room in a safe condition
and serves as a check that the valve is working.
A shut-off valve should be fitted in the supply pipe to each item of equipment. This
should be turned off when the equipment is not in use, and at the end of the school day.
11
In order to meet the requirements of the COSHH Regulations, the LEV system for heattreatment equipment should be checked every 14 months.
4.2
Brazing hearth and/or chip forge
Weekly check
•
•
•
•
4.3
Check condition of air and gas flexible hoses.
If fitted, check functioning of spark igniter.
Check function of gas shut-off valve.
Visually check extraction system.
Crucible furnace
Note In most schools this equipment is used infrequently. Therefore the checks below
should be made before use, rather than on a regular basis.
Before use
• The crucible should be inspected for damage or cracks. Any crucible showing
•
•
•
•
•
•
5
signs of damage should be immediately discarded.
Check condition of all personal protective equipment.
• Eye protection/face shields should be free of scratches and fit the user
properly.
• Gloves should be of an appropriate size, sufficiently flexible to use and free
of holes.
• The buckles on aprons should fasten correctly.
• Spats should fasten correctly.
If a tilting type of crucible furnace is used, check that the tilt mechanism
functions correctly.
If the crucible is lifted out of the furnace and placed in a pouring ring, check that
the lifting tongs and pouring ring are a good fit on the crucible.
If fitted, check functioning of spark igniter.
Check function of gas shut-off valve.
Visually check fume-extraction system.
Guide to cutting speeds
Whilst this section is not directly about maintenance, using the most appropriate speed
will prolong the life of cutting tools and machines, and will therefore reduce the
amount of maintenance and repairs needed. It is possible to do quite complicated
calculations in order to find the optimum speeds for machines such as drilling machines, milling machines, metal-turning lathes and wood-turning lathes. However, in a
busy workshop it may be difficult for a teacher to find time constantly to change the
speed of a machine; often a machine will be set at an ‘average’ speed which will cope
with most situations. It is possible to apply some general guidelines for speeds, as
discussed overleaf.
12
As a general rule, the speed should decrease as the size of the cutting tool or work
becomes larger.
Harder materials should be drilled at a slower speed than softer materials. One
exception is acrylic, for which a slower speed minimises the risk of swarf melting, resolidifying and jamming the tool.
5.1
Drilling
Drill speeds are given in revolutions per minute (rpm). An approximate guide to
speeds that will apply to most materials is given below.
Drill size
3 mm
6 mm
8 mm
12 mm
Speed
3000 rpm
1500 rpm
1000 rpm
800 rpm
5.2
Wood-turning lathe
Large-diameter pieces of work should be turned at a slower speed than smaller items.
The speed can be increased as the workpiece becomes more cylindrical. Often a fairly
heavy cut at a slow speed is more effective at removing materials than a light cut which
will only remove dust and will blunt the tool more quickly. A fairly average speed for
starting most work is 1000 rpm. When glass papering, the speed can be increased.
5.3
Metal-turning lathe
The general rule is that softer materials are turned at faster speeds than harder
materials but the diameter of the material is important, with larger sizes being turned at
slower speeds than smaller sizes. As a guide, 20 mm diameter mild steel should be
turned at about 1440 rpm. 20 mm diameter aluminium should be turned at about 12 000
rpm. If the tailstock chuck is being used for drilling, then the speeds for drilling
machines should be used as a guide.
5.4
Milling machine
Assuming a 12 mm diameter end mill is being used to cut mild steel, the end mill
should rotate at about 1450 rpm. On aluminium, the end mill should rotate at about
11 000 rpm.
13
14
4 April 2006
DATE OF
SERVICE AND
INSPECTION
centre sharpened.
15
Burrs removed from short tool rest. Rotating centre checked. Driving
REPAIR/SERVICING WORK REQUIRED/CARRIED OUT AND REMARKS
Fred Bloggs
SIGNATURE OF PERSON
CARRYING OUT SERVICE/
INSPECTION
4 April 2006
DATE WORK
WAS DONE
Fred Bloggs
SIGNATURE OF PERSON
CARRYING OUT WORK
REQUIRED
Make …Union Graduate…………… If electrical, details of phase/ power, etc. ………3 phase 440 volts………………………………………….
Type of equipment …Wood turning lathe……. Serial No. ………123456 AB…………. Location …Workshop 2…………………………………….
Note: This sheet is an example. A blank sheet, which can be copied, is on the next page. An electronic version can be downloaded from the members-only part
of our web site, www.cleapss.org.uk, as part of file DL254.
Appendix: EQUIPMENT REGISTER AND MAINTENANCE LOG
16
DATE OF
SERVICE AND
INSPECTION
17
REPAIR/SERVICING WORK REQUIRED/CARRIED OUT AND REMARKS
SIGNATURE OF PERSON
CARRYING OUT SERVICE/
INSPECTION
DATE WORK
WAS DONE
SIGNATURE OF PERSON
CARRYING OUT WORK
REQUIRED
Make ………………………………. If electrical, details of phase/ power, etc. ……………………………………………………………………
Type of equipment …………………………. Serial No. ………………………………………. Location …………………………………………
EQUIPMENT REGISTER AND MAINTENANCE LOG
School D&T Department
Was this manual useful for you? yes no
Thank you for your participation!

* Your assessment is very important for improving the work of artificial intelligence, which forms the content of this project

Download PDF

advertisement