The following safety precautions or guidelines are generally adopted for every metal cutting or machining shop. They must be strictly followed for safety. Specific safety guidelines for some of the machine process like lathe, drilling, shaping, planning slotting, grinding, milling, and finishing operations are also described in the following sections.
1. One should use the correct tools and work holding devices recommended for the process.
2. One should hold the work piece and tool securely on the machine.
3. One should clamp the tool correctly. An overhanging tool may cause catastrophic failure of the tool, work piece or the machine tool.
4. One should not try to remove chips from the machine with your hands.
5. Never use compressed air from mouth. Use brush.
6. One should not touch a job-piece with bare hands while doing inspection or removing it from the machine. Use gloves always.
7. One should operate the machine at recommended operating conditions based on work material and tool material combination and other cutting conditions specified.
8. One should use recommended coolant depending upon work-tool material combination.
9. During machining ductile materials, use chip breakers and chip guards.
10. One should re-sharp the tools immediately when it starts producing rough surfaces on the job-piece or produces chatter.
11. One should not run the machines at speed higher than recommended. It may produce vibrations and chatter and damage job-piece, tool, or both.
12. Provide sufficient approach and over travel distances wherever necessary.
13. In case of power failures, switch off the machine and retrieve tool from the workpiece.
14. One should wear goggles to protect eyes from flying chips.
15. Machines are governed by the old clinch garbage input, garbage output. The skill of the operator is often the limiting factor for the machining operation.
16. Stop machine before attempting to clean, removing tool or workpiece.
General Safety Guidelines while Working on Grinding Machines
1. Grinding wheels badly worn or cracked should be replaced
2. The grinding wheel should be properly balanced while mounting.
3. One should ensure that no combustible or flammable materials are nearby that could be ignited by sparks generated by grinding wheels during grinding operations.
4. One should allow the grinding wheel to reach full speed before stepping it into the grinding position. Faulty wheels usually break at the start of an operation.
5. Always use the face of the grinding wheel that is meant for grinding.
6. One should slowly move job-pieces across the face of wheel in a uniform manner. This will keep the wheel sound.
7. Grinding wheels should be checked properly timely for soundness. Suspend the wheel on a string and tap it. If the wheel rings, it is probably sound.
8. One should not use a grinding wheel that has been dropped or dealt with a heavy blow, even if there is no apparent damage.
9. Before using a new grinding wheel, let it run for a few seconds at the full speed to check and make sure that it is perfectly balanced.
10. One should not operate the grinding wheel beyond its bursting speed.
11. Follow the manufacturer’s instructions for the correct use of the grinding wheels.
12. Always wear goggles during grinding or allied processes.
Safety Precautions while Working on Lathe Machine
1. One should always be sure that all guards are in place before running the machine.
2. Always clamp the work and tool properly with correct size of work and tool holding device.
3. Always keep the machine clear of tools.
4. Machine should be stopped before making measurements or adjustments.
5. Wear an apron or a properly fitted shop coat. Goggles should also be used.
6. One should remove necktie, wrist watch and jewellery while working.
7. One should not operate the lathe until he knows the proper procedure.
8. One should check the work frequently when it is being machined.
9. One should check the face-plate or chuck by hand to be sure that there is no danger of the work striking any part of the lathe.
10. Stop the machine and remove chips with pliers. One should not remove the chips by hand.
Safety Precautions while Working in Casting shop
Similar to other manufacturing processes, the following safety precautions need to be taken in the casting shop also.
1. One should use mask to avoid excessive inhalation of the dust, which may cause serious problem to health.
2. Always wear protective clothes to keep safe from the heat radiating from the melting process.
3. All foundry men should wear protective clothes, glasses, shoes, and gloves while handling molten metal for casting process.
4. One should be alert as severe burn injury can result from spillage of the molten metal.
5. Always use proper ventilation to protect from molten metal fumes and gases that evolve from the mould during pouring.
6. One should not touch hot moulds and castings.
7. Always use earplugs to safeguard against the heavy noise.
8. One should always keep clean the work area.
Safety Precautions while Working in Welding shop
(A) Gas welding
1. One should not use a leaking gas cylinder.
2. One should not handle oxygen cylinders, valves, regulators, hoses or fittings with oily hands.
3. Welder should not mix the gases in one cylinder.
4. No one should transfer the gas from one cylinder to another.
5. One should clearly mention on the cylinders the type of gas in it (i.e. oxygen, acetylene, etc.).
6. One should use nose masks where the local exhaust ventilation is not practicable. Insist the safety officer to provide proper ventilation system.
7. Always avoid skin contact with fluxes, which contain fluorides. If they will penetrate the skin, they produce severe irritation.
8. No one should weld the parts, which are coated with toxic material such as lead, cadmium, zinc, mercury, or paint containing toxic before materials. Any such coatings must be removed prior to welding.
9. Acetylene gas should not be brought in contact with the unalloyed copper directly (except in torch) which may result in a violent explosion.
(B) Arc welding
1. One should use protective clothing and eye protection devices while performing arc welding operation, otherwise radiation from electric arc will damage the retina of eyes. One has to be sure that other people standing nearby also uses eye-protection devices from ultraviolet rays.
2. Always use ear protection devices such as muffler because excessive noise caused during the process of arc welding may cause temporary or permanent hearing loss.
3. Welder should keep clothing and gloves dry.
4. Always keep welding cables free of grease and oil.
5. One should prevent the non-insulated portion of the electrode holder from touching the welding ground or job-piece when the current is on.
6. Always keep the body insulated from both the work and the metal electrode holder.
7. One should carry out the welding process by standing on the insulating material like dry wood rather than on a grounded metal structure.
8. It is easier and safer to establish an arc on a clean surface than on a dirty or rusty one.
9. Always turn the welding machine off when it is not in use.
10. One should not change the polarity switch when the machine is under use. This will burn the surface of the switch and the resulting arc can cause injury to the welder.
11. Always avoid using electrode holders with defective jaws or poor insulation.