| 摘要 |
<p>PROBLEM TO BE SOLVED: To control the irradiation position of the laser beam so that the laser beam constantly irradiates the center line of a groove, and to prevent the effect of the spatter, etc., to be generated during the welding in achieving the butt welding of a base metal to be welded with the laser beam. SOLUTION: A groove 4 and a part near a key hole 7 are simultaneously photographed by an imaging means during the butt welding with the laser beam, the brightness of the pixels of each image of the groove 4 and the part near the key hole 7 is detected in the direction orthogonal to the welding direction, respective brightness distribution curves for the groove 4 and the key hole 7 are prepared, the deviation between the brightness distribution curved for the groove 4 and the brightness distribution curve for the key hole 7 is obtained, and the irradiation position of the laser beam is controlled so that the shape of the obtained brightness deviation curve is symmetrical with reference to the center position of the brightness distribution width of the change point on the brightness distribution curve for the groove 4.</p> |
