| 摘要 |
<p>PROBLEM TO BE SOLVED: To prevent generation of unjointed portions and penetrated portions by surely carrying out the welding with a laser light regardless of the existence of a spacing between upper and lower flanges at a lap joint part or the size of a spacing volume. SOLUTION: A distance sensor 81 is installed in a manner to sandwich both flanges 11a, 11b and to be opposed against a pressing roller 4 for pressing the upper side flange 11a at a given fixed interval x. The distance h to the reverse face of the lower side flange 11b is detected and outputted to the first computing part 83. At the first computing part 83, the lap joint thickness (x-h) is computed by subtracting distance h from the fixed interval x. At the second computing part 84, the spacing volume y is sequentially computed by subtracting upper and lower flange thickness f1, f2 from the lap joint thickness (x-h). At a controller 9, the laser processing head 4 is moved in upper/lower direction corresponding to the spacing volume y every time, so as to change and adjust the focal position of the laser light. While the spacing volume y is continuously computed and the focal position is continuously changed and adjusted, a continuous irradiation of the laser light is carried out against the longitudinal direction of the lap joint part.</p> |
