The spot welders roller are constructed of sheet steel and steel sections welded, finished to the machine tool, undergo rigorous treatments of standardization, so as to ensure high accuracy, combined with excellent rigidity and resistance to stress. Heads roller bearing with rolling bearings, sliding contacts silver suitably machined to machines tool to ensure adequate electrical contact for the welding current, cooled by circulation of the coolant. The movements of such heads is served by three phase asynchronous motor driven by an inverter for adjusting the speed of motion and welding. Welding transformer water-cooled impregnated under vacuum to ensure good continuity of spot welding. Welding control digital type Micro8 Rollers.