Plasma cutting, also known as plasma arc cutting, is a thermal process that involves the use of an ionized gas jet at temperatures exceeding 20,000°C to melt and remove material from a cut. The process involves the creation of an electric arc between an electrode (cathode) and the workpiece (anode). The electrode is positioned within a gas nozzle that is cooled by either water or air, which helps to narrow and intensify the arc, resulting in the formation of a high temperature and high velocity plasma jet.

 When the plasma jet comes into contact with the workpiece, recombination occurs and the gas returns to its normal state, emitting a significant amount of heat in the process. This heat causes the metal to melt, and the gas flow expels the molten material from the cut. Typically, plasma gases such as argon, argon/hydrogen, or nitrogen are used. However, air can be used as a replacement for these inert gases, although it requires a special electrode made of hafnium or zirconium. The use of compressed air in this variant of the plasma process makes it a highly competitive method for cutting carbon-manganese and stainless steels up to a thickness of 20mm. Inert gases are preferred for achieving high-quality cuts in reactive alloys.

 Plasma arc cutting is capable of cutting a wide range of electrically conductive alloys, including plain carbon and stainless steels, aluminum and its alloys, nickel alloys, and titanium. Originally, this method was developed to cut materials that could not be effectively cut using the oxy-fuel process. Typically, the component or sheet to be cut remains stationary while the plasma torch is moved. Furthermore, due to the relatively low cost of the plasma torch compared to the manipulation equipment, it is common to equip cutting tables with multiple torches. In addition, Specialized equipment allows for the execution of plasma arc cutting underwater as well.