Analysis of Resistance Spot Welding Characteristics with Flat Electrodes for Reducing Indentation in Excavator Exterior Parts

Resistance spot welding (RSW) inherently creates indentations on the material surface due to the applied pressure from the upper and lower electrodes. While indentations are not a major concern for internal components, they significantly affect the surface quality of external panels. To mitigate this issue, industrial practices involve increasing the diameter and curvature of the electrode tip; however, this approach cannot completely eliminate indentations, necessitating additional post-processing for their removal. Using large-area flat electrodes could theoretically prevent indentation, but this leads to excessive contact area, resulting in weakened joint strength and increased welding current requirements.In this study, a novel approach was proposed to minimize indentation by applying large-area flat electrodes to external components while maintaining conventional-sized electrodes for internal materials. Resistance spot welding was performed under various process conditions, and the weld strength and indentation depth were evaluated. Furthermore, the effects of different process parameters on weld quality and indentation formation were analyzed to determine optimal conditions that minimize indentation while maintaining sufficient joint strength.