Multiple Nd:YAG laser beams are irradiated onto a common point on a workpiece surface and combined in order to increase weld penetration depth. A high peak-power pulsed laser beam is used as a part of the combination. A spatter loss problem is severe under high peak-power laser beam conditions, thus a preventive condition is investigated.
The deepest weld penetration is obtained underneath a spatter loss condition which is determined by the peak power of a pulsed laser beam in welding using two laser beams in combination.
This result is reflected in three combined laser beams. Full penetration welds of 10 mm thick stainless steel (304) are obtained at a welding speed of 5 mm/s by laser beams of a total average power of 5 kW in a bead-on-plate test. These results demonstrate that three laser beams can be combined successfully for greater result in comparison to the results obtained by up to two combined laser beam welding described in a previous study.