Relationship between Shaving Allowance and Cut Surface in the Shearing Process by Step Taper Shaped Punch using Finite Element Method

Abstract

One of the important processes in the metal forming field is the shearing/blanking process. Thisprocess is used for separating sheet metal into the product and scrap. Therefore, the quality of productdirectly depends on the quality of the cut surface. Nowadays, the conventional shaving process is used toproduce the high quality of the cut surface needing the smooth cut without cracks. However, the shearing/blanking process is necessary before doing the shaving process. Therefore, the relationship of the numerousprocess parameters between the shearing and shaving processes to obtain the good quality cut surfacesuch as the clearance in the shearing process and the shaving allowance in the shaving process is verycomplexity and causes the time and cost production. As the mentioned problem, the step taper punch wasproposed and investigated because this process can be continuously shear and shave as the one punchstroke, hence, reducing the step of the operations and cost and time production. Although this process wasinvestigated in the past researches, the relationship between the shaving allowance and the cut surface wasnot done. Moreover, the past researches were investigated by experiments. Therefore, the mechanism andthe effect of the process parameters can not be theoretically clarified. The optimal taper angle was 6 degreewhich was investigated by experiments in the past research. Therefore, in this study, the relationship betweenthe shaving allowance and the cut surface with the 6 degree taper angle was investigated by using thefinite element method. As a result, the shaving allowance directly affected on the material flow, the stressdistribution and the cut surface also. The smooth cut decreased and the cracks increased as the shavingallowance increased. The optimal shaving allowance was approximately 0.2 mm. Moreover, the quality ofcut surface obtained by the step taper punch was better than it obtained by the conventional shaving. Therefore,the step taper punch can be used as the process reducing the process operation. From the results, itindicated that the FEM simulation could be a useful tool for predicting the cut surface features in the steptaper shaped punch shearing process.