A plasma cutter machine cannot run independently without external supplies. There are two basic things required to get a plasma cutter going, one is air, and the other is electricity. However, other things are also needed to accomplish a successful plasma cutting. Here we will touch upon various apparatuses, personal gear, and topics integral to plasma cutting.
Which Tools Are Needed To Make A Plasma Cutter Cut?
A plasma cutter machine has to hook up to an electrical power system, whether to a local electricity supply or a generator. A plasma cutter may run on 110V or 220V AC voltage as required by its ratings. Also, the power outlet has to be compatible with the plasma cutter plug to prevent unwarranted failure.
Compressed Air (Air Compressor or Bottled)
Plasma cutters cut through metals by transferring superheat energy from a torch to the workpiece. Air is used as plasma gas to produce the plasma and transfer heat to the workpiece. An air compressor (either standalone or built-in) provides compressed air to the plasma cutter machine to achieve cutting. Air pressure and flow requirements will differ among plasma cutters. However, handheld plasma cutters usually require around 4-8 cubic feet per minute (CFM) airflow delivered at 90-120 psi pressure to produce a precise cut.
The plasma cutter owner's manual contains detailed information about airflow and pressure requirements. Normally, air compressors with a thinly higher rating than the owner's manual will do. However, air compressors with 1.5-2 times more airflow and pressure ratings than the owner's manual are preferable.
An air filter is a small device that ensures the plasma cutter gets clean and dry air free from moisture, dirt, condensation, and other contaminants from the air compressor. The air filter fits on the gas hose, and compressed air passes through it before reaching the plasma cutter. By absorbing pollutants from the air, an air filter contributes to the extended working life of plasma cutter consumables, the torch, and the machine itself. Also, clean and dry air helps improve cut quality. So an air filter saves costs by prolonging the machine's lifespan, improves efficiency, and helps make high-quality cuts.
A grinder is a tool having a grinding wheel driven by a motor. Grinding wheels can be of various styles, like grinding stones, flap wheels, sanding discs, cutoff wheels, wire wheels, etc. With the wheel up, a grinder can cut, chop, clean, polish, shape, grind, sand, and more. In plasma cutting, wire wheels are helpful because they are like wire brushes that can clean a surface before and after cutting. Before cutting, a wire wheel can remove rust, paint, or oil from the surface to ensure good viewing of the cut line. After cutting, a wire wheel can remove splatter and clean the surface around the cuts down to the plain metal. Other wheels can also be helpful to smoothen out the surface as needed.
The clamp hooks the earth lead to the workpiece completing the ignition circuit via the torch and the metal workpiece.
What Personal Protective Gears Needed for a Plasma Cutter Operator?
What is the Sequence of Steps to Start Cutting with a Plasma Cutter?
1. Connect the air compressor to the power outlet, switch it ON and allow the air pressure to reach a sufficient level
2. Position the workpiece and clean the surface of any coating or painting using a grinding wire wheel
3. Mark the cutting line on the metal workpiece
4. Connect the grounding cable (work lead) to the plasma cutter. Attach the ground clamp to the workpiece. Be careful not to clip the clamp to the workpiece area will fall separated after the cut.
5. Put on personal protective equipment (PPE)
6. Turn ON ventilation, exhaust hood
7. Plug the power cord of the plasma cutter into the mains power outlet
8. Plug the air hose into the plasma cutter
9. Install torch consumables onto the torch. If present, switch the torch lock ON.
10. Plug the torch lead into the plasma cutter
11. Suitably stand to be safe from sparks and metal piece drop after the cut. Ensure a clear view of the workpiece.
12. Run a test for smooth movement and motion of the plasma torch
13. Set appropriate cutting amperage based on the thickness of the metal about to be cut
14. Position the torch a few mm above the surface of the metal workpiece and press the plasma switch on the torch handle. The plasma arc will gush out in force.
15. Move the plasma arc over the cutting line across the metal workpiece in a measured motion to cut.
16. Continue the cut until the sounds of the metal piece striking the ground can be heard.
17. Allow the metal piece to cool off.
18. Now collect the metal piece for the intended use.
Also Read: What Is Plasma Cutting – How Does It Work?
Plasma Cutting Safety: Hazards and Precautions
Hazards and Preventions for Eye and Skin
During plasma cutting, the plasma arc reaches an extremely high temperature resulting in the emission of intensive electromagnetic (EM) radiation. The emitted EM radiation concentrates in the Ultraviolet (UV) to infrared (IR) spectrum ranges. These EM radiations can burn the skin and damage the eye. Wearing appropriate clothing suits, such as a welding jacket, will protect the skin. Direct viewing of high-intensity EM radiation is severely harmful to the eye. Especially exposure of the eye to the blue light radiation of the UV spectrum can permanently impair the retinas. This damage can happen without even the person realizing it. Therefore during plasma cutting, it is strongly recommended to wear eye protection gear. Eye protection gears are available in various designs, each with its advantages. Some of them are shielded helmets, face shields, OTG safety glasses, cutting lenses, welding/torch goggles, shade-5 glasses, etc. People assisting in plasma cutting also need to wear eye protection gear.
Fire Hazards from Cutting and Flammable Substances
Some fire hazards of plasma cutting are flying sparks, falling slags, and hot metal pieces that cause burn injuries. For protection, the operator has to wear a fire-retardant welding jacket. The presence of flammable substances within the cutting area poses a threat of accidental fire. There is a high potential that continuous sparks and heat of the plasma will fire on nearby flammable materials such as chemicals, fuels, gases, powder, and paints. Such fire may create a frightful situation without even one noticing. So it is highly recommended to remove all flammable materials from the working zone before the start of a cut. Alternatively, flammable materials may be covered using fire-proof covers. Because of the risk of explosion, it is advised not to cut any drums, tanks, or containers that probably contain combustible, flammable, explosive, toxicant, poisonous, or reactive materials.
Hazardous Air and Ventilation Requirements
Plasma cutting produces smoke, gases, dust clouds, and many other air pollutants that are unhealthy to breathe and damaging to the respiratory system. In addition to the above-said gas byproducts, plasma cutting may produce metal oxides, carbon dioxides, ozone, and other toxic substances that are hazardous to health. Also, the extreme heat of the plasma generates tiny microparticles that consummate easily into the lungs. According to Occupational Safety and Health Administration (OSHA), inhaling the toxicants, particulates, and gases mentioned above is the cause of many health effects. It can be said plasma cutting without adequate ventilation is dangerous for health. So, it is advisable to wear proper respiratory protection gear and install requisite ventilation in the work area to protect against hazardous air contaminants.
Plasma cutting over coated metals releases toxic fumes into the air. Therefore, before cutting coated metals - like adonized metals, galvanized steels, electroplated metals, powder-coated metals, painted metals, cadmium-plated metals, nickel coated metals, chromium-coated metals, and lead-plated metals, it is best to scrape off their coatings. If coated metals are about to be cut without the removal of coating materials, then there has to be a proper exhaust system in place.
Proper Electrical and Earth Ground Connection
A plasma cutter operates the plasma stream at a high voltage of around 110 to 400 VDC. Direct contact with such high voltage results in fatal electric shock and severe injury. Regular checkup of cables, connections, grounding, and wearing protective gear is essential to ensure an electrically safe work environment. Here are the recommended checks and preventive measures.