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Plasma Cutting (PAC)



Plasma Cutting (PAC) is an electric arc cutting process that severs metal by melting a localized area with a constricted arc of super heated gas, which melts the base material at high velocity. The plasma torch has a recessed electrode which uses electrical energy to heat the gas which may be air, nitrogen or oxygen. The gas is delivered to the torch at high pressure (100 psi) and is forced through a constricting orifice held in close proximity to the base material being cut.

Plasma Cutting is ideal for many industrial applications because it can cut any electrically conductive metal if its thickness and shape permit full penetration by the plasma jet. Plasma Cutting can cut nonferrous materials and is faster than oxy-fuel cutting for ferrous materials that are less than two inches thick.

Among the available process variations are:

1. Conventional plasma cutting where the arc is constricted by the nozzle only and no shielding gas is added, nitrogen or air serves as the cutting gas; (Air systems are very popular with manual PAC)

2. Oxygen plasma arc cutting, which requires the use of special consumables that are made to operate in an oxidizing atmosphere, is widely used for mechanized cutting of steel since the additional oxygen to the cut zone can boost the cutting speeds by approximately 25%;

3. Water injection cutting, which utilizes water introduced inside the nozzle to provide additional arc constriction to improve cut surface quality and increase cutting speeds.

A recent process variation is precision plasma where arc constriction is increased dramatically to provide a high energy density for improved cut squareness and cut quality. Most Plasma Cutting equipment for conventional cutting utilizes only an orifice gas, generally nitrogen or air. Argon or nitrogen can also be used in some applications. Nitrogen/hydrogen and argon/hydrogen are used in special cutting applications, particularly for stainless steel, aluminum and with plasma arc gouging.

Why Plasma Cutting?