An Experimental Study for the Effect of Contact Stress of Blank Holder and Punch Velocity on Crack Ratio of Fine-Blanked Surface

Abstract

In this study, the parameters (i.e., contact stress at the die-sheet interface and the punch velocity) were measured by the installation of film stress sensors in the fine-blanking die. A regression model was established to investigate the degree of importance of the parameters and their interaction on reducing the crack ratio of fine-blanked surface. Analysis of variance (ANOVA) was then performed to check the adequacy of the regression model. The optimal results of the regression model agreed well with the experimental result. The regression analysis indicated that the contact stress have a major influence, followed by the interaction and the punch velocity. The importance of the interaction means that the ability of contact stress in crack ratio reduction depends on the level of punch velocity. The result could be useful to facilitate an improvement in the quality of the fine-blanked parts by the optimization parameters.