Mechanism of Wrinkling in Deep Drawing of Sheet Metals : 3rd Report, Theory of Conical Die Drawing

Abstract

A theoretical investigation of wrinkles arising in conical flange part during deep drawing of circular sheet blanks by means of conical formed die without blankholder is reported. In this case, we assumed the formula of wrinkles arising in deformed conical shell and as a buckling problem of conical shell the energy method was used. The critical wrinkling condition in terms of the ratio (thickness of blank)/(drawing diameter) was determined, by purely theoretical means, if the cone angle of the die, material constants of sheet metal blank, drawing ratio and lublicant were given. And further more, it was found possible to predict the similarity for wrinkling limit.