摘要 |
Distance to the upper face of workpieces W sandwiched between electrode rollers 15 and 16 is measured by a range sensor 41 that has a predetermined positional relationship with the electrode rollers 15 and 16 (STEPs 1, 3). Correction is made based on the distance found by the range sensor 41 by moving the pair of electrode rollers 15, 16 with reference to the workpieces W so that an angle Rx between a straight line L0 connecting centers of the pair of electrode rollers 15, 16 and the surface of the plurality of workpieces W is preset angle (STEP 5). |