A New Approach to Spot Weld Feedback Control

Improvements in resistance spot weld (RSW) quality in sheet metal are desired for manufacturing consistency and cost reduction in the automotive business. This paper reports on a new feedback control concept for RSW that employs a unique process stabization technique. The process is stabilized such that mechanical instabilities and contact resistance variations are minimized. After process stability has been achieved, the weld is driven to expulsion and terminated. Under specified process and control conditions, termination of the weld coincides with formation of a high quality spot weld.