Experimental and numerical analysis verification of effect of work material in cylindrical deep drawing focusing on material anisotropy and die radius shape

This paper presents the effect of work material on the formed shape in a cylindrical deep drawing using a die with circumferentially varying die radius dimensions. In the deep drawing, the material anisotropy causes unevenness, called “ears”, on the cup edge. Because of the additional trimming process, the occurrence of earing leads to material loss and additional production processes, resulting in low productivity. The earing suppression has usually been conducted by material development to suppress material anisotropy. It has been shown that a die with different die radius dimensions has been proposed, and that the ear shape can be changed by the die only. However, the effects of material thickness, diameter, and anisotropy on the formed shape have not been reported. In this paper, the effects of forming conditions of mainly the material were investigated by experiments and finite element analysis in cylindrical deep drawing using a die with circumferentially varying die radius dimensions. As the sheet thickness was thicker and the blank diameter was larger, the ear height increased due to the large material inflow. Stainless steel, aluminum alloy, and copper materials can be used to suppress ear height if appropriate forming conditions are set. It has also been clarified that there are conditions of die placement that suppress the ear height in correlation with the in-plane anisotropy of the material.