Suppression of non-uniform deformation using die shape in cylindrical deep drawing

Abstract. This study presents a cylindrical deep drawing method that suppresses non-uniform deformation by die shape. In the cylindrical deep drawing, the material inflow in the circumferential direction varies due to the material anisotropy, resulting in unevenness at the edges of the cup, called the ear, after forming. Since the ears are usually trimmed after forming, there are concerns that the ear reduces yield rate and productivity due to the increased number of processes. The main approach study to the suppression of non-uniform deformation due to anisotropy has been the development of materials with suppressed material anisotropy. However, material development has been difficult to introduce because of the increased costs involved, and there has been a lack of development from the press process side. Therefore, this study clarified the effect of die shoulder radius on forming shapes in “Multiple R die” for cylindrical deep drawing by experiments and finite element analysis. Ear height can be suppressed if forming is performed in such a way that the effects of anisotropy and die shape cancel out each other by experimental and analysis results.