On the Drawability of Sheet Metal in Noncircular Cups

Abstract

The drawability of sheet metal, hitherto based on and restricted to the drawing of round cups, as in the Swift test, is generalized to cover noncircular cups. The way to measure the extent of drawing is first generalized from the drawing ratio to the draw-in at the completion of the cup. It is demonstrated that the draw-in at the completion of the cup depends on the choice of the product boundary as well as on the size, the shape, and the orientations of the blank. “Drawability of the material” is, strictly speaking, a meaningless term, although the drawability of different materials can be compared in the same drawing process and that of the same material can be compared in different processes. The concept of drawability in noncircular cups, so defined and analyzed, also serves to indicate the degree of utilization of a material in any particular drawing operation.