Numerical and experimental investigation of geometric parameters in projection welding

Resistance projection welding is widely used for joining of workpieces with almost any geometric combination. This makes standardization of projection welding impossible. In order to facilitate industrial applications of projection welding, systematic investigations are carried out on the geometric parameters by numerical modeling and experimental studies. SORPAS, an FEM program for numerical modeling of resistance welding, is developed as a tool to help in the phase of product design and process optimization in both spot and projection welding. A systematic experimental investigation of projection welding a disc to a ring with a triangular ring projection has been carried out to study the influence of the geometric parameters in various metal combinations. In these studies, SORPAS has been used as a supporting tool to understand the relationship of the parameters and the phenomena occurring in projection welding. Thickness of disc and ring, as well as height and angle of projection has been used as geometric parameters to obtain the best weld quality. The experiments have been used to determine the size of the welding lobe and the bond strength, while the numerical investigations have been used to show the temperature distribution using the different geometric parameters. The numerical simulations with SORPAS can explain the differences in the welding lobes and bond strength. This shows SORPAS as a strong tool in the product development of workpieces for resistance projection welding. Based on the numerical and experimental investigations of the geometric parameters in projection welding, guidelines for selection of the geometry and material combinations in product design are proposed. These will be useful and applicable to industry.