Plasma CuttingPlasma cutting uses the heat and pressure generated by a constricted electric arc to cut material. DC power sources are used and need high open circuit voltage. The process is operated using the 'transferred arc' mode, in which the arc is maintained between the electrode and the material to be cut; a pilot arc is maintained between the electrode and the constricting orifice. The cutting process uses high plasma gas flows and active gases. The features of the process are a high energy density heat source to give melting and ejection of molten material in the high velocity plasma jet. It can be used for a wide range of ferrous and non-ferrous alloys and is particularly suited to cutting of aluminium alloys and stainless steels. Plasma gases may be argon/hydrogen mixtures, nitrogen, air, or even oxygen, and water-cooled electrodes with tantalum tips are often used. Secondary gases may be CO2, N2, or air. Welding fume is generally high but some modern equipment is capable of maintaining low fume levels. The process tends to be noisy and generates high levels of radiation.
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