A note on mathematical models of cup drawing by the guerin and marform processes

Abstract Both the Guerin and Marform processes are flexible-die forming operations that use rubber-pad pressure, the essential difference between the two being that the latter uses a blank-holder. Flexible-die forming has many advantages over rigid-die forming and these two processes find many applications such as in the forming of flanges, beads and ridges (Guerin), and flanged cups, spherical domes, and square and rectangular shells (Marform). In this paper, investigations into cup drawing by the two processes are reported. Using factorial experimental design, mathematical models for cup drawing by the two processes have been obtained. In both cases blank thickness is found to be major factor governing the limiting drawing ratio.