Patent ID: 9073146
Filing Date: 2015-07-07
Classification: B23K

Abstract:
1. A pressure control method for a spot welding apparatus, wherein the spot welding apparatus includes a first welding electrode; a pressure actuator configured to apply a pressure to a second welding electrode, the electrodes holding therebetween a workpiece; and a sub-pressure actuator configured to bring a sub-pressure unit into contact with the workpiece so as to apply a sub-pressure to the workpiece; and wherein the spot welding apparatus is configured to perform spot welding on the workpiece by applying current between the first welding electrode and the second welding electrode to which a preset pressure is applied while holding the workpiece by using the first welding electrode, the second welding electrode, and the sub-pressure unit; the pressure control method comprising: a first step of applying to the workpiece one of a preset initial pressure by the pressure actuator through the first welding electrode and the second welding electrode holding and pressing the workpiece therebetween and a preset initial sub-pressure by the sub-pressure actuator through the sub-pressure unit being in contact with the workpiece, and subsequently applying the other one of the initial pressure and the initial sub-pressure; and a second step of applying to the workpiece one of a preset setting pressure by the pressure actuator through the first welding electrode and the second welding electrode and a preset setting sub-pressure by the sub-pressure actuator through the sub-pressure unit, and subsequently applying the other one of the preset setting pressure and the preset setting sub-pressure, the second step being performed after the first step, wherein the first step and second step are alternately repeated until an acceptable range is reached.