The principle of plasma cutting
What is plasma cutting?
Plasma is described as the fourth aggregation state of material. Due to a sufficiently high temperature, the electrons can leave the atomic core and the material is an electrically conductive mixture of ions, electrons and partly atoms. The mixture is outwardly electrically neutral. In an electric arc, the plasma enables the charge carrier transfer, e.g. between an electrode and the workpiece. Simultaneously, the current flow effects an energy input to the plasma which is necessary to maintain the temperature needed for the plasma state.
Plasma cutting means that an arc is produced between an electrode and the workpiece. The arc is locally constricted by at least one nozzle and pressurised with a gas. The extremely high kinetic energy of the plasma arc melts the material and the molten material is driven out of the kerf. 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 arc is ignited by the increased power. The small heat affected zone, high cutting speeds and the cut quality are particularly huge advantages of this method.