The Principle of Plasma Cutting

Plasma is a thermally high-heated, electrically conductive gas. That means that neutral atoms dissolve into ions and electrons by adding ionisation energy. This energy can be produced by very high temperatures or strong electric fields. Generally, plasma reacts like a gas with a neutral outside effect.

Plasma cutting is a thermal fusion cutting method which is realised with an electric arc constricted by a nozzle. The cutting process starts first with a pilot arc which is ignited between nozzle and electrode (cathode) by high voltage. The pilot arc has low energy and ionises partly the atoms between plasma torch and workpiece. As soon as the pilot arc touches the workpiece, the electric circuit closes and the main are is ignited by the increased power. The high thermal energy of the arc and the high kinetic energy of the plasma gas melt the material and the molten material is driven out of the kerf. The small heat affected zone and high cutting speeds are particularly huge advantages of this method.

Different process variants: