Characterization of micro resistance spot welding on aluminum electrolytic capacitors

Abstract Resistance spot welding (RSW) processes are applied across a diverse range of manufacturing processes in industry with the objective of permanently joining two metal parts. RSW occurs due to heat generated on focal points by the resistance that an electric current flow (AC or DC) encounters when passing through metallics pieces pressed against each other by electrodes. This study is based on a design of experiments (DOE), focused on the manufacture of aluminum electrolytic capacitors, and seeks to characterize the influence of RSW parameters (electrical current density, weld time and electrodes pressure) on the tensile strength of the weld joint formed between aluminum alloy AW3003 and a low carbon steel sheet coated with copper and tin by electrodeposition. The DOE consists of a sweep on the electrical current between 12kA and 20kA, weld times 8ms and 12ms and pressures 0.3Mpa and 0.4Mpa. The welding interface of the specimens was also analyzed by SEM and EDS, revealing different types of morphologies. The results obtained highlighted the electrical current as the main influence factor on the tensile strength, also enabling the identification of different types of morphology on welding interface. The observed tensile strength results for the studied parameters ranged from 376N to 1095N (average), and an optimized combination of parameters based on a statistical analysis in Minitab software is suggested at 18kA, 12ms and 0.3Mpa.