Spot welding control method and apparatus using a servo welding gun

摘要

A spot welding method and apparatus having electrode tips one of which is driven by a servo motor. In the method and apparatus, it is determined whether or not an abnormal condition occurs. The abnormal condition includes (a) squeezing some obstacle between the electrode tip and a workpiece, (b) a temperature adhesion of the electrode tips with the workpiece, (c) uneven pressurizing of the workpiece by the electrode tips, (d) a weld nugget dispersion, and (e) a too large electric resistance between the electrode tips and the workpiece. When such abnormal condition is detected, some counter measure is taken to prevent or decrease the abnormal condition.