A study on the improvement of formability for elliptical deep drawing processes

The punch and die corner radii, the lubricant condition, the working speed, the blank-holding force, the friction force and the clearance change the formability of the deep drawing process. In general, sheet metal forming may involve stretching, drawing or various combinations of these basic modes of deformation. The influence of the punch and die corner radii is of great importance in the design of sheet metal working processes. Recently, most of the research for the sheet metal deep drawing process has been performed on the formability of an axisymmetric shape, but there are not any concrete reports on the formability of a non-axisymmetric shape. In addition, the conventional corner radii of the punch and die have been determined by trial-and-error using industrial experience and post-processing tests, and only approximate corner radii of the punch and die have been presented. In order to obtain the optimal products in the deep drawing process, elliptical deep drawing tests were carried out with several corner radii of the punch and die. In this study, the optimal corner radii of the punch and die in the deep drawing process with a non-axisymmetric blank shape are proposed. Research has been carried out using diverse technologies including experimentation and the finite element method.