MIG (Metal-arc Inert Gas) or MAG (MetalActive Gas-arc) (their only difference isthe gas used for the protection of weldpool), is a welding process that developedduring the 50s that has become more andmore important in the recent years. Theprogress of technological innovation andcost reduction of electronic products haveallowed this development: as result semiautomaticwelding machines have beendeveloped at affordable prices. This ensurehigh productivity, if compared to machinesused in other processes. Heavy Duty MIG MAG WELDING MACHINE MANUAL W/O ACC 400/3PH - 400A/ @ 30% (400A) @60%(340A)-@ 100%(250A) SYMPLEX 420 5T5.421.152 WELDING PROCESS