WELDING CONTROL METHOD AND APPARATUS

摘要

A welding control method is described for automatic welding machines in which the welding gun is moved by a robot successively to a plurality of welding spots on the workpiece where the welding gun is closed to firmly clamp the workpiece while applying pressure thereto and then energized to perform a welding operation. The welding control method comprises the steps of: closing the welding gun with no work clamped between the electrode tips thereof before actually performing the welding operation at a first welding spot on the workpiece so as to take as a reference the observed degree of opening of the gun arms; storing the observed degree of opening; presetting for each welding spot a specific degree of opening of the gun arms which corresponds to the thickness of the workpiece at that spot; detecting the degree of opening of the gun arms when the welding gun is closed at each welding spot on the workpiece; determining a difference between the detected degree of opening and the reference degree of opening; and comparing said difference with said preset degree of opening to check for any abnormal condition. Abnormal operation of the welding gun can thus be prevented.