Investigation of a novel modified die design for fine-blanking process to reduce the die-roll size

In order to reduce the die-roll size in the fine-blanking process, a modified die structure was proposed, which an indenter arranged along the die profile was set on the cutting edge. The indenter can be defined by four structure parameters. To investigate the effect of these four die structure parameters and evaluate their degree of importance on the die-roll size, three different levels of each die structure parameter were applied in the fine blanking process of a specially designed triangular tooth using FEM. The optimized die structures were determined considering the effect of reducing die-roll size, the die lifetime and the prevention of crack on the cutting surface. Extra simulations were carried out to verify the effect of the modified die. To explain the mechanism of the modified die, a theoretical model was established according to the features of die structures. The former FEM results were taken as examples to demonstrate the theoretical model. To test the feasibility of this modified die, experiments were performed on the part of automobile synchronizer slipper. In addition, the relationship between the blank holder force and the die-roll sizes in the different fine-blanking processes was studied during the experiments.