Effect of tool design on formability in deep drawing by applying compressive force on flange

This paper presents a new deep drawing process which applies compressive force on a flange for forming a deep cup effectively. This method uses a punch with a convex and a die, and optimum tool design was investigated using the finite element method (FEM) in order to prevent the formation of defects. First, the effect of the punch configuration was investigated. As a result, a cup with a uniform side wall thickness was obtained under the condition that the punch convex length was greater than the blank thickness and the punch top corner radius was appropriate. It was possible to obtain the deep cups by decreasing the clearance between the punch convex and the die. However, dimensional accuracy decreased with the decrease in the clearance. Based on these results, two-steps process using a backward punch was proposed, and deep cups having high dimensional accuracy was formed successfully by this method