Formability of Warm Deep Drawing Process for AA1050-H18 Pyramidal Cups

In this present work, a statistical approach based on Taguchi Techniques and finite element analysis were adopted to determine the formability of pyramidal cup using warm deep drawing process. The process parameters were thickness of blank, temperature, coefficient of friction and strain rate. The experimental results were validated using a finite element software namely D-FORM. The AA1050 H18 sheets were used for the deep drawing of the pyramidal cups. The blank thickness by itself has a substantial effect on the effective stress and the height of the pyramidal cup drawn. The reduction of the drawing force was perceived with the increase of temperature. The effective stress increases with the increase of friction due to increase of normal pressure between die and blank. The formability of the pyramidal cups was outstanding for the surface expansion ratio greater than 2.9. The strain hardening exponent values for 0.8, 1.0 and 1.2 mm thick blank sheets have been found to be 0.28, 0.30 and 0.33 respectively. The formability of deep drawn pyramidal cups is difficult with blank thickness less than 1mm.