Part II. Analytical Investigation

Abstract

In cup-drawing, an element of metal whose initial diameter exceeds the mean cup diameter is under conditions of true radial drawing, which is combined with plastic bending under radial tension when it reaches the die profile, whereas other elements will be subject to stretch-forming under biaxial tension, which will be combined with bending under tension if they fall within the punch profile.In this part an analysis of the stresses and strains in the region of true drawing is attempted, taking into consideration the effects of bending, thickness changes, strain-hardening, blank-holding force, die-profile friction, and tool geometry, but not of anisotropy in the material. Theoretical punch load-travel diagrams, process work, maximum punch loads and strains are compared with recorded experimental results over a wide range of tool design, operating conditions, and materials.It is suggested that the theory can be applied with confidence in predicting punch loads and strokes and in prescribing power and strength ratings for deep-drawing presses.