Control of Blank Holder Force to Eliminate Wrinkling and Fracture in Deep-Drawing Rectangular Parts

The predominant failure modes in stamping of sheet metal parts (deep drawing and stretch forming) are wrinkling and fracture. In many cases these defects may be eliminated by appropriate control of the Blank Holding Force (BHF). This paper summarizes the results of a recent study on the formability of rectangular parts from aluminum alloy 2008-T4. Wrinkling and fracture limits have been determined and BHF control methods have been developed to eliminate defects, improve part quality, and increase the draw depth.