| 摘要 |
<p>PROBLEM TO BE SOLVED: To cope with scanning speed of a laser beam and also to enable laser welding while a weld line position is detected with high precision. SOLUTION: In butt welding between a sheet 15 and a plate 17, a plane mirror 23 is oscillated in an area of a specific angle around the shaft 29 by a oscillating unit 31, thereby oscillating a laser beam 19 in a diagram orthogonally crossing a weld line W in the direction vertical to the paper surface. A plasma beam 41 generating each from the sheet 15 and the plate 17 in laser beam irradiation is such that the intensity is different mutually because the focal position of the laser beam 19 is different between the sheet 15 and the plate 17, and that the timewise change of this plasma beam intensity is detected by a photo sensor 39; then, a computer 49 judges whether the oscillation center of the laser beam 19 is deviated to the sheet 15 or to the plate 17 with respect to the weld line W, controlling the operation of the oscillating unit 31 so as to correct the deviation.</p> |
