Plasma sources

Plasma cutting

From a physical point of view, plasma is zionized gas composed of ions, electrons and even neutral particles. Because very high temperatures are reached in the plasma arc, plasma is used in industry for the thermal cutting of metallic materials.

The principle of plasma cutting lies in that the neutral gas, e.g. compressed air, is drawn at high speed through the nozzle into an electric arc, which is usually generated by a high-voltage spark. Through this process, the gas is zionized, the electrical circuit closes with the surface of the metal material, and a high-temperature plasma arc is formed that melts the metal being cut while the gas flowing at a high velocity simultaneously removes the molten metal from the cutting gap.

In the area of plasma cutting, we cooperate with the following companies:

What is plasma?

Plasma is often also called the fourth state of matter (the other three are the well-known solid, liquid and gaseous states). It is an ionized gas consisting mainly of positive ions and electrons (negative particles). Since the starting material is a gas without an electrical charge, plasma contains approximately the same number of particles with a positive and negative charge, so it appears to be electrically neutral from the outside. However, it has excellent conductivity due to its structure.

The gas can be ionized by supplying enough energy to allow the valence electrons (simply speaking - the electrons in the outer layer) to break away from the atoms or molecules. Atoms depleted of an electron have a positive charge and are called cations (particles with an "extra" electron are called anions). When the supply of energy ceases, the cations merge with the electrons to form gas again. Thermal energy is used most commonly.

The principle of the plasma torch function

The main function of a plasma torch is to generate a directed plasma stream that melts the material at the cutting point. DC or AC current or another kind of discharge is used as a source of energy for heating the gas. The torches most commonly use DC current, as they provide a more stable flame compared to alternating current, are quieter, easier to operate, have a lower consumption of electrodes and electricity, and have somewhat less thermal wear.

In the torch, there is a nozzle from which inert gas, or air, flows. This nozzle contains a cathode. If the material is conductive, it can be cut using an anode, which may be in the torch as well. An electric arc is formed between the electrodes, heats up the flowing gas to a high temperature and transform it into plasma. The high velocity of the flowing gas ensures the removal of the molten material from the cutting point.

Variants

Plasma torches are generally water-cooled. The basic design has several variants. In addition to conventional torches, dual torches are used, where a secondary auxiliary shielding gas flows around the plasma stream and separates the cutting area from the atmosphere, thereby allowing a cleaner cut. The auxiliary gas can also be replaced with water, which also cools the cutting point in addition to protecting it. Furthermore, special designs are used for the high-precision cutting of thinner materials and others.

Plasma cutting applications

Plasma is most commonly used for cutting sheets and plates from steel and other metals, although other materials (including non-conductive materials) can be cut with plasma as well.  It is commonly used for a material thickness of up to about 150 mm.   It can be used for manual cutting or in CNC cutting machines such as those offered by our company.