LASER WELDING METHOD FOR GALVANIZED STEEL SHEET

摘要

PURPOSE:To eliminate the need for the cleaning of a welding device and to allow the stable welding by condensing laser light by a condenser lens having the focal distance longer than the splashing distance of zinc spatters from above the galvanized steel sheet, then executing the welding. CONSTITUTION:The galvanized steel sheet 6 which is an object to be welded is disposed in the position of an out-of-focus length 11 lower than the focus 12 of the condenser lens 5 and welding is executed by the long focal lens 5 longer than the max. splashing distance 10 of zinc spatters. The zinc spatters 9 generated from a zinc plating layer 7 existing on the surface of the galvanized steel sheet 6 do not arrive at the condenser lens 5 and the contamination of the condenser lens 5 by the zinc spatters 9 is prevented. Compressed air is blown as a side gas 31 though a side nozzle 30 to the working surface of the steel sheet 6. The zinc spatters 9 are removed from around the object to be welded and II system and the welding in clean environment is executed.