The Influence of Redrawing and Reverse Drawing on Thinning of Curved Bottom Cylindrical Cup

This research work studied the influences of deep drawing techniques on thinning of aluminum alloy grade 5052 H32 cup; conventional drawing, redrawing, and reverse drawing. It was found that by using conventional drawing, redrawing, and reverse drawing caused cup thinning of 11.3%, 7.4%, and 10.7% of sheet thickness, respectively. The position of maximum thinning occurred on the straight wall closed to punch radius of the cup in the case of conventional drawing. In the case of redrawing, thinning could be reduced due to drawing in step 2 caused stretching only in the curved area at the bottom of the cup. Therefore, the thickness on the straight wall remains unchanged after first step. As for reverse drawing, drawing in step 1 only changed the curved bottom cup. Therefore, it didn’t contribute to reduce thinning in the straight wall area slightly above the punch radius where the maximum thinning occurs in step 2.