The effect of the Weld Pitch on Shunting in Robotic Resistance Welding

Abstract

The shunting of welding current during the process of spot resistance welding is a phenomenon which should be taken into consideration both at the design stage of load-bearing structures and during the process of their fabrication. As regards the intensity of shunting, the most important parameter is the distance between neighbouring welds (weld pitch). In spite of technological guidelines concerning the size of the pitch, scientific publications lack information about the correlation between the distance between welds and the size of the weld nugget. The article presents results of individual research aimed to analyse the effect of the pitch size on the diameter of the weld nugget. The welding process was performed using a robotic welding station. Verification (measurements of the weld nugget diameter) was based on advanced ultrasonic testing methods including scanning acoustic microscopy (SAM) and the RSWA (Resistance Spot Weld Analyser) devise provided with a phased-array mosaic transducer.