An investigation of step taper-shaped punch in piercing process using finite element method

Nowadays, the technology on sheet metal forming has rapidly grown especially in the automotive and electrical industry. Furthermore, the strong concern is to obtain better product quality with lower cost. Therefore, in this study, the piercing process using the step taper-shaped punch was investigated in order to improve the pierced surface quality. Although past research has been studied on this process, most of them were studied with experiments. Therefore, the theoretical mechanism has not been clarified. In this study, the authors focused on the theoretical explanation of the piercing process using step taper-shaped punch (STSP) by using the finite element method (FEM) and also verified these FEM simulation results with experiments. As a result, the mechanism and effects of the taper angle could be theoretically clarified on the material flow analysis and stress distribution in FEM. Moreover, the suitable taper angle of approximately 6° obtained in this study corresponded well with past research done with experiments. Finally, the correspondence of the FEM simulation and experiment results indicated that the FEM simulation could be a useful tool to predict the pierced surface features of the piercing process using the STSP.