The redrawing of cups at a redraw ratio of 3 using an annular urethane pad

Abstract

A novel redrawing process has been developed to redraw cups at a redraw ratio of 3. In this process, a cup drawn by the conventional deep drawing process is reverse redrawn by repeatedly squeezing an annular urethane pad held between the bottom of the cup and the container of the pad. It is similar to the Maslennikov’s technique for drawing cups from flat sheet metal; the difference being that the present process makes use of a cup instead of the flat blank. Redrawing experiments with aluminium cups indicate that with sufficient friction at the urethane–cup interface and proper lubrication of the die, very deep cups can be produced by this process. Results from these experiments are reported in this paper.