When we talk about modifications, maintenance, repairs, revisions of molds, inevitably we are talking about laser welding. A system already present since many years in mold industry, which gives the possibility to make adjustements, maintenance, repairs and modifications even on cold molds, without overheating the involved parts, without affecting the structure of the worked mold, guaranteeing all geometries and mechanical work near the welding, without creating distortions or the loss of mechanical features.