Properties of hemispherical cups drawn using a flexible tool

Experimental investigations into the drawing of hemispherical cups were conducted with aluminium and copper blanks using the recently developed friction-actuated blank-holding technique. Blanks of different diameters and thicknesses were used in the experiments. Urethane pads of different hardnesses were also tested. Conditions for consistently producing wrinkle-free cups were established. To ascertain the quality of the cups produced, the variations of the thickness, the equivalent strain imposed on the metal, the hardness and the roughness along the cup wall were measured. Results from these investigations are presented in this paper.