RESISTANCE WELDING CONTROL METHOD

PROBLEM TO BE SOLVED: To form a nugget diameter of all workpieces in a proper range in a state free of dust, in resistance welding of three layered workpieces. SOLUTION: There is provided a resistance welding control method in which welding is performed with constant power control so that instantaneous power value during the welding is equal to a power set value Pr. In the method, the power set value Pr is changed with the welding elapsed time t in accordance with a predetermined power target pattern. The power target pattern is a pattern in which the power target pattern becomes an initial value Ps at the welding starting time, gradually increases to be a first peak value Pp1 at a first welding elapsed time T1, then gradually decreases to be a base value Pb at a second welding elapsed time T2, and thereafter gradually increases to be a second peak value Pp2 at a welding completion time Te. Each nugget diameter can be made nearly equal with the first peak value Pp1, and an excess heat input is suppressed with the base value Pb, thus preventing dust from being generated. COPYRIGHT: (C)2010,JPO&INPIT