Advances in resistance welding for body‐in‐white

This paper describes the developments in the control of spot welding from Bosch Rexroth with particular reference to body‐in‐white applications. The Bosch Rexroth MF system uses 1 kHz rather than conventional 50 Hz in the control of spot welding and DC current rather than AC at the weld gun. The several benefits of this arrangement are discussed including lower power and energy losses, lighter cabling and a more compact weld transformer. Also described is a new ultrasonic adaptive control system developed by Bosch Rexroth which enables the growth of the weld nugget to be monitored and recorded for traceability.