LASER-BEAM WELDING METHOD AND LASER-BEAM WELDING APPARATUS

摘要

While a laser-beam application position is moved along a locus which circularly or elliptically circles around a locus center so as to cross a weld line (L) that is a boundary between a first metal plate (W1) and a second metal plate (W2) overlapped with each other, the locus center is moved in a direction parallel to a weld line (L). A moving direction of the laser-beam application position is set such that the laser beam is first applied to the first metal plate (W1) and then to the second metal plate (W2) when the laser beam passes through an unmelted zone of the first metal plate (W1) and the second metal plate (W2). The unmelted zone is located downstream of a range (X) through which the laser beam has already passed in the direction parallel to the weld line (L).