Abstract: A laser lap welding method by irradiating of a laser beam from one side of a plurality of overlapped workpieces (1, 2), the method includes the steps of: scanning (La) the laser beam in the forward direction along a predetermined section of the workpieces; reversing the scanning direction of the laser beam at a terminating end (t) of the predetermined section; scanning (Lb) the laser beam in the backward direction and terminating of the irradiating of the laser beam onto the predetermined section, wherein the scanning of the laser beam in the backward direction is offset from the scanning of the laser beam in the forward direction such that a part of weld bead (12) formed by the laser scanning in the backward direction overlaps the weld bead (11) formed by the laser scan in the forward direction.

Abstract: To provide a laser lap welding method including: performing lap welding (11; 21) by irradiating a laser beam (La) on a plurality of overlapped workpieces (1, 2); and irradiating, after a very short interruption time period of the laser beam irradiation, a defocused laser beam (Lc) on a terminating end (12; 22) of the lap welding. Preferably, the laser lap welding method including: interrupting the irradiation of the laser beam for a very short time period and moving, during the interruption time period, the optical axis of the laser beam from the terminating end of the lap welding to the side of the starting end of the lap welding; and irradiating a defocused laser beam from the position to which the optical axis of the laser beam is moved, to the terminating end of the lap welding.

Abstract: A laser lap welding method by irradiating of a laser beam from one side of a plurality of overlapped workpieces (1, 2), the method includes the steps of: scanning (La) the laser beam in the forward direction along a predetermined section of the workpieces; reversing the scanning direction of the laser beam at a terminating end (t) of the predetermined section; scanning (Lb) the laser beam in the backward direction and terminating of the irradiating of the laser beam onto the predetermined section, wherein the scanning of the laser beam in the backward direction is offset from the scanning of the laser beam in the forward direction such that a part of weld bead (12) formed by the laser scanning in the backward direction overlaps the weld bead (11) formed by the laser scan in the forward direction.