Improved consistency of resistance spot welding with tip voltage control

Resistance spot welding is the key metal joining technique for high volume production in the automotive, biomedical and electronics industry. Weld quality is one of the dominant issues for the welding community. Thus a major focus of the spot welding research has been to control the process to improve the consistency of the welding process. In order to improve the consistency of RSW, control of the voltage at the electrode is considered. To evaluate this approach it is compared to open loop voltage control and constant current control. Open loop voltage control mode is the original control mode for resistance spot welding, while constant current control mode is the present state of the art control technology for large scale resistance spot welding. The paper finds that constant tip voltage did reduce the variance of the weld spot diameter.