Approximate Calculation Formula of Drawing Force by Curved Surface Die (1st Report) : Yield limit is constant-its calculation

Abstract

This paper is concerning to the drawing force by the curved surface (hyperbolic revolution) die when the yield limit of drawing material is constant at the die-inlet and outlet. Here the drawing force obtained by way of summing up (1) the force to deform the material, (2) the frictional force acting between the die-wall and material, and (3) the force required to bend the material fibers at the die inlet and each points on die-wall. The author examined the formula to look for the die shape by which the minimum drawing force would be attained, and made cleared that there was an ideal die shape, which could be determined only by the frictional coefficient between the material and die-wall and regardless of the area-reduction ratio. Next, he investigated the shapes of some dies on the market and the other factors.