The plasma welding process was introduced to the welding industry in 1964 as a method of bringing better control to the arc welding process in lower current ranges

Today, plasma retains the original advantages it brought to industry by providing an advanced level of control and accuracy to produce high quality welds in miniature or precision applications and to provide long electrode life for high production requirements.

The plasma process is equally suited to manual and automatic applications. It has been used in a variety of operations ranging from high volume welding of strip metal, to precision welding of surgical instruments, to automatic repair of jet engine blades, to the manual welding of kitchen equipment for the food and dairy industry.
How Plasma Welding Works

Plasma Arc vs. Tig ArcA plasma is a gas which is heated to an extremely high temperature and ionized so that it becomes electrically conductive. Similar to GTAW (Tig), the plasma arc welding process uses this plasma to transfer an electric arc to a work piece. The metal to be welded is melted by the intense heat of the arc and fuses together.

In the plasma welding torch a Tungsten electrode is located within a copper nozzle having a small opening at the tip. A pilot arc is initiated between the torch electrode and nozzle tip. This arc is then transferred to the metal to be welded.

By forcing the plasma gas and arc through a constricted orifice, the torch delivers a high concentration of heat to a small area. With high performance welding equipment, the plasma process produces exceptionally high quality welds.

Plasma gases are normally argon. The torch also uses a secondary gas, argon, argon/hydrogen or helium which assists in shielding the molten weld puddle thus minimizing oxidation of the weld.
Equipment Required List

* Power Supply
* Plasma Console (sometimes external, sometimes built in)
* Water re-circulator (sometimes external, sometimes built in)
* Plasma Welding Torch
* Torch Accessory Kit (Tips, ceramics, collets, electrodes set-up gages)

List of Plasma Welding Features and Benefits
Feature Benefit
Protected electrode Protected electrode allows for less electrode contamination. This is especially advantageous in welding materials that out gas when welded and contaminate the unprotected GTAW electrode.
Length of arc benefit due to arc shape and even heat distribution Arc stand off distance is not as critical as in GTAW. Gives good weld consistency. No AVC needed in 99% of applications, sometimes even with wirefeed.
Arc transfer is gentle and consistent Provides for welding of thin sheet, fine wires, and miniature components where the harsh GTAW arc start would damage the part to be welded.
Stable arc in welding Reduces arc wander. Arc welds where it is aimed. Allows and arc starting tooling in close proximity to weld joint for optimum heat sinking.
Minimal high frequency noise in welding Minimal high frequency noise once pilot arc started, thus plasma can be used with NC controls. Another benefit lies in welding applications involving hermetic sealing of electronic components where the GTAW arc start would cause electrical disturbances possibly damaging the electronic internals of the component to be welded.
Arc energy density reaches 3 times that of Tig Causes less weld distortion and smaller welds. Gives high welding speeds
Weld times as short as .005 seconds Extremely short and accurate weld times possible for spot welding of fine wires, accurate weld times combined with precision motion devices provide for repeatable weld start/stop positions.
Equipment options offer to 10,000 Hz Offers a wide range of pulsing options for varied. pulsing up applications.
Low amperage art welding
(as low as 0.05 amp) Allows welding of miniature components or good control in downsloping to a weld edge.
Arc diameter chosen via nozzle orifice This feature assists in predicting the weld bead size.