MIG Welding Machine (Metal Inert Gas)
The arc which is struck by direct contact between the wire electrode and the workpiece, is maintained at a constant length by the interaction of electrical parameters. The power source used is invariably of the rectified dc type. Both, constant voltage and constant current type power sources are in use.
Depending upon the work material, the shielding gas may be argon, helium, nitrogen, carbon dioxide, hydrogen, and their mixtures. When inert shielding gas is used the process is more popularly known as MIG (metal inert gas) welding and when CO2 is used as the shielding gas it is referred to as CO2 welding or MAG (metal active gas) welding.
GMAW is an all-position semi-automatic welding process through its automatic versions is also available. GMAW is a very versatile process and can be used for welding all metals for which compatible filler wires have been developed. However, its typical applications include medium-gauge fabrication such as structurals, earth moving equipment, plate and box girders, and automobile bodies. This process has great potentials for use with robotic welding systems.
Plasma-MIG Welding Machine
This process, as the name implies, has been developed by combining the features of plasma arc welding and MIG welding processes. It has two variants; one with separate non-consumable tungsten electrode and the other uses the torch nozzle as non-consumable electrode.
Essentially plasma-MIG welding process differs from the existing GMAW process in that the electrode wire is enveloped in a plasma sheath which controls heat and droplet transfer in such a way that much higher speeds and deposition rates are attained that possible with GMAW process.
This process can be used both for welding and surfacing. Most of the materials that can be welded by GMAW can as well be welded by this process and at much faster rates.