Patent ID: 6903298

Claim:
A method of producing a series of electrical resistance spot welds in one or more workpieces, each workpiece being positioned for each weld between a servomotor driven movable electrode and an axially opposing fixed electrode, the method comprising: setting target values for electrode displacement and electrode force, and an initial total welding current and its duration; making a pre-determined number of spot welds using a weld controller to apply the welding current between the electrodes and to control the servomotor in applying the electrode force and advancing the movable electrode to make a spot weld indentation in the workpiece with an electrode displacement; measuring the electrode force and electrode displacement after a spot weld; comparing the measured electrode force and electrode displacement values with the corresponding target values; and, if either of the force or displacement values are not within a tolerance range of the target values altering said welding current during one or more succeeding spot welds to bring the electrode displacement and/or force values for the succeeding spot welds within said tolerance ranges.