Nozzle Solidified weld metal Molten weld metal Shielding gas Consumable electrode (machine fed) Gas supply Work Power source Shielding gas Wire drive may be located in welding gun handle or at wire reel. Contactor Wire drive Wire reel Regulator with flowmeter Controls for governing wire drive current, gas flow, and cooling water, if used. Figure 5-4.  Metal inert gas (MIG) welding process.  Figure 5-5.  MIG welding equipment. 5-4