Importance of Plasma Cutting Safety

It would be a grave mistake to disregard the important of plasma cutting safety. Just because the plasma cutter is easy to use, that doesn’t make it appropriate for haphazard use. Here are some tips to keep you safe while operating one of these machines.

1. Never operate a plasma cutter in a wet environment. You must understand that the plasma cutter uses electricity to start and stay running. Its electrical circuit lies between the torch and the surface being cut. Anything that comes in contact with the object being cut becomes a part of that electrical circuit including water. Okay, especially water since water conducts electricity just like some metals do. So use a plasma cutter in dry environments only.

Plasma Cutting Safety

2. Do not retrieve cut pieces of metal while you’re cutting. Do not remove work pieces while the grand cable is attached. And do not remove a ground clamp while cutting. Doing so places you at high risk for electrocution. For this very reason, insulated boots and gloves are required equipment in any serious place of business.

3. Make sure the ground cable is well secured onto the piece that’s being cut (NOT the piece that will fall off). Arcing near the ground clamp is a sign that the clamp is damaged, unsafe, and needs replacing. Failing to make a safe and secure connection is a sure-fire way to experience electrical shock. The ground clamp must always remain secured prior to releasing a plasma cutter's trigger.

4. Don't use a plasma cutter without proper eye protection. Eye protection isn't just for shielding flying debris. It’s also for shielding against burning. Plasma cutters produce highly intense ultraviolet and infrared waves that can burn the retina, cause cataracts, and damage the skin even if proper precautions aren’t taken.

5. Keep your plasma cutter away from flammable materials. Don’t store or use your cutter near gasoline or other combustible solutions.

6. If you use a heavy duty plasma cutter - that is, one with a excessive noise level, wear ear protection as well.

7. Use a plasma cutter in a well ventilated area. Plasma cutters melt metal and the gases released are toxic.

Arc Welding Process - Plasma Arc Welding

Plasma Arc Welding Robots
Plasma Arc Welding Robots (PAW) uses high temperature plasma gas to melt two materials together. This method offers many advantages including faster welding and more precise, deeper welds.

Plasma arc welding robots take this intense application up a notch. Not only do robots offer superior performance, they also save money and time.

How Plasma Arc Welding Works:
The intensity of plasma arc welding is the result of unique torch design. As with other arc welding applications, the arc is created between the tungsten electrode and a work piece, but with plasma arc welding the electrode is encased in a copper nozzle. This nozzle channels the plasma gas and arc through a small hole at the tip.

Plasma Arc Welding

What You Stand to Gain With A Plasma Arc Welding Robot:

Exact Welds
The plasma arc welding application is already known for creating deep, narrow welds. Plasma arc welding with robots is even more consistent and precise. Robots are designed to handle repetitious tasks with ease.

More Savings
Manual plasma arc welding requires greater skill than other applications. With the introduction of robots you will save on time and money that is normally spent training workers. Robots have a terrific return on investment and offer freedom from mistakes and wasted materials.

Danger Removed
Manual plasma arc welding is a painstaking and hazardous process. With robots, workers can oversee the welding process away from the heat and light of the plasma arc welding area. Fewer hazards in the workplace mean more savings.

Faster Throughput
Plasma arc welding robots make a fast process even faster. They are programmed to move efficiently and work continuously.

Conventional Plasma Arc Cutting

The plasma jet generated by conventional "dry" arc constriction techniques was introduced in 1957 by Union Carbide's Linde Division. In the same year, Dr. Robert Gage obtained a patent, which for 17 years gave Union Carbide a virtual monopoly. This technique could be used to sever any metal at relatively high cutting speeds. The thickness of a plate could range from thin sheet metal to plates as thick as ten inches (250 mm). The cut thickness was ultimately dependent on the current-carrying capacity of the torch and the physical properties of the metal. A heavy duty mechanized torch with a current capacity of 1000 amps could cut through 10-inch thick stainless steel and aluminium. However, in most industrial applications, plate thickness seldom exceeded two inches. In this thickness range, conventional plasma cuts were usually bevelled and had a rounded top edge. Bevelled cuts were a result of an imbalance in the heat input into the cut face. A positive cut angle resulted because the heat energy at the top of the cut dissipated as the arc progressed through the cut.

Plasma Arc Cutting

This heat imbalance was reduced by placing the torch as close as possible to the workpiece and applying the arc constriction principle, as shown in Figure 1. Increased arc constriction caused the temperature profile of the electric arc to become extended and more uniform. Correspondingly, the cut became more square. Unfortunately, the constriction of the conventional nozzle was limited by the tendency of increased constriction to develop two arcs in series, one arc between the electrode and nozzle and a second arc between the nozzle and workpiece.

This phenomenon was known as "double arcing" and damaged both the electrode and nozzle. Double arcing severely limited the extent to which plasma cut quality could be improved. Since the introduction of the plasma arc process in the mid-50's, considerable research has focused on increasing arc constriction without creating double arcing. Plasma arc cutting as performed then is now referred to as "conventional plasma cutting." It can be cumbersome to apply if the user is cutting a wide variety of metals and different plate thicknesses. For example, if the conventional plasma process is used to cut stainless steel, mild steel, and aluminium, it is necessary to use different gases and gas flows for optimum cut quality on all three metals.




Conventional plasma cutting predominated from 1957 to 1970, and often required very expensive gas mixtures of argon and hydrogen.

Plasma cutting gas

CNC plasma cutting machine, usually have higher no-load voltage and working voltage, in the use of gases such as high ionization energy (ie) air or nitrogen, hydrogen, stable plasma arc required voltage will be higher. When the current, voltage of certain enthalpy of arc to improve is improving and cutting capability is improved. If the enthalpy increases, the diameter of reducing jet velocity, and increase the gas can often gain faster cutting speed and better cutting quality.

1. Oxygen can improve the speed of cutting low carbon steel materials. Use oxygen cutting, cutting mode and flame cutting very imagine, high-temperature high-energy of plasma arc cutting speed faster, but makes use of high temperature oxidation to cooperate with the electrodes, meanwhile to the electrodes arcs, in order to prolong the impact protection of electrode life.

Plasma cutting process

2. Hydrogen is often used as an auxiliary gas and other gas mixture with action, like the name of the H35 (hydrogen gas is 35%, the volume fraction of the argon plasma arc cutting ability) is one of the strongest gases, which mainly benefited from the hydrogen. Because the hydrogen can significantly raise arc voltage, make hydrogen plasma jet has high enthalpy, when blended with argon plasma jet, the cutting ability is greatly increased. General on thickness 70mm above the metal materials, common argon and hydrogen as cutting gas. If use water jet of argon + hydrogen plasma arc further compression, still can obtain higher cutting efficiency.

3. Air contains volume fraction about 78% of nitrogen, so use by the formation of the air cutting with nitrogen and hang slag during cutting very imagination; Air also contained volume fraction about twenty percent of oxygen, because the existence of oxygen with air, the cutting speed of low carbon steel material is also high; Meanwhile the air is the most economic work gas. But when used alone air, there will be cutting hang slag and incision oxidation, increase nitrogen, and electrode and nozzle life lower can also affect work efficiency and cut costs. Because of plasma arc cutting generally use constant-current or steep drop the power supply, the characteristics, current highly increase nozzle changed little, but will make arc length increase and lead to increased arc voltage, thus make arc power increased; But at the same time also can make exposed to the environment, the arc length growth increased the energy loss of arc beam.



In two factors under the condition of the comprehensive function, the former action often offset by completely by the latter, it will make effective cutting energy decreases, and cause cutting capacity reduction. Usually the performance was cutting jet blew force is abate, incision of the lower residual slag increased, the upper edge over melting and appear round, etc. In addition, the plasma jet from the ideology consideration, jet in diameter is leaving muzzle expands outward, nozzle highly increase inevitably lead to the incision width increasing. So, choose as far as possible to improve small nozzle height cutting speed and cutting quality are beneficial, but, nozzle height is too low may cause the double arc phenomenon. Adopt ceramic nozzles outside can be set to zero, nozzle height vent end direct contact with that is cut surface, can obtain good effect.

CNC Plasma Cutting Machine

4. Nitrogen is a kind of common work in a higher gas, power supply voltage conditions, nitrogen plasma arc has better stability and argon gas higher jet energy than, even if it is cutting the liquid metal viscosity materials such as stainless steel and nickel-based alloy, incision of inferior hang slag quantity are few. Nitrogen can be used alone, also can use with other gas mixture, such as automation cutting often use nitrogen or air as gas, this two kinds of gas has become the standard gas high-speed cutting carbon steels. Sometimes nitrogen are being used oxygen plasma arc cutting of arcs gas.

5. Argon in high temperature and almost not with any metal happening reaction, argon CNC plasma cutting machine, very stable. And by use of the nozzle with electrodes have higher service life. But the argon plasma arc voltage, low enthalpy is not high, cutting ability is limited, and air compared the thickness of the cutting cutting about will reduce 25%. In addition, argon protection environment, the surface tension of molten metal larger, than in nitrogen environment around 30% higher, so there will be more hang slag problem. Even use argon and other gas mixture of cutting will also have viscous slag tendency. Therefore,now rarely used alone on pure argon plasma cutting.

Used Plasma Cutters

Why used Plasma Cutter
You can find used plasma cutters internet and in the actual world. If you discover used plasma cutter you have to make in no doubt that it is in fine condition and, more importantly, you have to find out if the component meets your requirements.

Use the following list of questions to assess any used plasma cutter that you find. When you have the answers, you will be in a much improved position to create a knowledgeable buying result.

Used Plasma Cutters - Manual cut

1. Is the cable insulation worn down from use?

2. Does the sever cut, rated cut, and quality cut of the match what I need?

3. Are the cuts still clean?
4. Has the machine ever been repaired or serviced?

5. Is there still a factory warranty?

6. Is there a power source at my business or home that matches the power requirements of the machine?

7. What is the duty cycle of the unit?

8. Are the diagnostic lights and controls functioning properly?

9. If I buy the machine do I get any consumables?

10. What is the condition of the internal components? (if they are in good condition then the owner probably taken good care of the machine)

Plasma Cutter Operation