Design of mechanical clinching tools for joining of aluminium alloy sheets

The purpose of this study is to propose the design method of mechanical clinching tools, which is used to join aluminium alloy sheets in automobiles. Based on the analytical model used to predict the strength of the mechanical clinched joint, the design method of clinching tools that can satisfy the required joint strength is proposed. The analytical model has been defined as a function of the neck-thickness and the undercut, which are the presented mechanical clinched joint geometry. And joint geometry is defined by the shape parameters of the clinching tools. To obtain the desired joint strength, the required neck-thickness and undercut are inversely calculated from the analytical model. The mechanical clinching tools that join Al6063 alloy sheets are designed by the proposed method. FE-analysis and mechanical clinching test were performed for optimal conditions obtained from the proposed design method. The result of the FE-analysis and that of the mechanical clinching test showed good agreement of the clinched joint geometry. The H-type tensile test for mechanical clinched joint was carried out to evaluate the strength of the mechanical clinched joint designed by the proposed design method. The result of the tensile test showed that the fracture load satisfied the required joint strength. Also, the top-hat impact test was performed to evaluate the feasibility of using mechanical clinching for automotive component assembly. The result of impact test showed that mechanical clinching was able to produce similar crash resistance as self-piercing riveting.