Plasma Cutter comprises a constricted opening through which an electric arc is sent through a gas. The gas can be shop air, nitrogen, argon, oxygen, etc. This elevates the temperature of the gas to the point that it enters to the fourth states of matter. We are known to the first three states of matter- solid, liquid and gas. The fourth and extended states of matter are termed as plasma by scientists. As the metal being cut is part of the circuit, the electrical conductivity of the plasma causes the arc to transfer to the work.

The bounded opening (copper nozzle) the gas passes through causes it to squeeze by at a high speed, like air passing through a venturi in a carburetor. This high speed gas cut through the molten gas. The gas is also directed around the perimeter of the cutting area to shield the cut.

In most of today’s plasma cutters, a pilot arc placed between tungsten electrode and copper nozzle is used to ionize the gas and initially generate the plasma prior to the arc transfer.

Another method that has been used is touching the torch tip to the work that creates a spark, and the use of a frequency at high level starting circuit. But neither of the latter methods is compatible with CNC (automated) cutting.

The swirl ring which is fixed above the electrode and causes the plasma to turn rapidly as it passes. When these parts are all referred to as consumables it is the electrode and nozzle that wear and require periodic replacement.

Computer Numerically Controlled (CNC) plasma cutters fully automate the production process. In today’s CNCs units are either expensive limited production computers made specifically for burning machines, or personal computers adapted to run the machines. Both provides the same cut quality and production speed.