Study of weld strength variability for capacitor discharge welding process automation

Abstract

The capacitor discharge welding (CDW) process is an autogenous, rapid solidification joining process ideal for joining small parts incorporating dissimilar metals. Potential applications include welding of solderless electrical contacts, cutting tool inserts, and automotive valves. Because of high cooling rates, in excess of 10⁶ K s^-1, the production rate for CDW processes is potentially very high. However, potential industrial users are hesitant to use the CDW process, owing largely to the unavailability of automated process control. The objective of the present study was to investigate the source of weld strength variability in CDW as a foundation for process automation and control. Results show that welding time significantly affects weld strength variability for both high thermal conductivity and high gas content materials, independent of the t_w/2RC ratio.