With metal inert gas welding an arc is struck between a consumable electrode and sheet metal.  There are two types of metal inert gas welding using either a constant or pulsed voltage DC power source.

• MIG (Metal Inert Gas), GMAW (Gas Metal Arc Welding) uses an aluminum alloy wire as a combined electrode and filler material.
• Welding parameters are controlled by the welding machine, the process is also called semi-automatic welding.
• MIG-process uses a direct current power source, with the electrode positive (DC, EP).
• Oxide layer is efficiently removed from the aluminum surface, which is essential for avoiding lack of fusion and oxide inclusions.
• The metal is transferred from the filler wire to the weld bead by magnetic forces as small droplets, spray transfer.
• There are two different MIG-welding processes, conventional MIG and pulsed MIG:
• Conventional MIG uses a constant voltage DC power source.
• Pulsed MIG uses a DC power source with superimposed periodic pulses of high current.

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