OPTIMIZATION OF NON-LINEAR DIE SURFACE IN EXTRUSION OF NON-CIRCULAR SECTIONS

In this paper an analytical method for noncircular shape extrusion is reported. With this method non-linear deformation field can be described with Hermit cubic spline which is prescribed by the boundary conditions of the die at its entry and exit. The Upper bound method has been used to obtain optimum coefficient of the tangential boundary conditions. The results show that the optimum tangential parameter and the extrusion force that determined by this method have good agreement with finite element method. Also physical modeling test show that optimum non-linear die could reduce extrusion force and strain variation than those using the linear die.