Comparing the effect of electrode geometry on resistance spot welding of aluminum alloys between experimental results and numerical simulation

With the tightened emission limits the amount of aluminum sheets in future body-in-white concepts is on the rise. Thus, there is a need for optimizing the joining techniques to fulfill the upcoming challenges linked to high volume production. Especially the electrode life for resistance spot welding as a reliable and established process needs to improve. In order to do so the effect of electrode geometries on the electrode life is investigated. It is shown that the radius of curvature, the size of the face diameter, and the cone angle influences the electrode life. The reason for this behavior is explained by a numerical simulation developed by the TU Dresden. Based on these findings, an analysis with the purpose of investigating an improved electrode geometry is conducted. It is shown that a domed electrode with a radius of curvature of 150 mm should be used. This electrode combines the ability to crack the oxide layer effectively while ensuring a sufficient area of contact between electrode and sheet.