Effect of Draw-In on Formability in Axisymmetrical Sheet Metal Forming

In the formability of sheet metal, distinction is made between the formability at the critical section, the formability of the material, and process efficiency. It is shown that draw-in has an adverse effect on the formability at the critical section, but greatly improves the gross process efficiency, which measures the extent to which the formability of the material is exploited in a particular process. The effect of draw-in on the strain distribution in the workpiece is shown in a triangular coordinate system for strains.