1. A system for teaching how to weld which allows training experienced welders in a shod amount of time CHARACTERIZED in that said system comprises: a base ( 2 ) from which six actuators ( 3 ) emerge which allow an upper platform ( 4 ) to be moved in six degrees of freedom; wherein from said base ( 2 ) a fixed bench ( 5 ) having a surface ( 6 ) on which a plate to be welded is mounted, emerges; wherein said upper platform ( 4 ) has an adaptor ( 7 ) on which a welding gun having a handle ( 10 ) is mounted; wherein on the tip of the gun ( 9 ) there is an electrode adjacent to the plate to be welded, said plate being attached to the surface ( 6 ) of said fixed bench ( 5 ); wherein said actuators ( 3 ) are connected to a sensor ( 11 ) and a controller ( 12 ) connected to an interface ( 13 ); and wherein said interface ( 13 ) is connected to a processor ( 14 ) which has a memory ( 15 ) and an alarm ( 16 ).