Analyses of Solid State Extrusion Process of Polymeric Materials by Pressure Dependent Yield Criteria

Abstract Among various methods to estimate extrusion pressure in solid state extrusion, Sachs's method1 is one of the most convenient and widely used ones. According to this method the equation for extrusion pressure is derived by taking accounts of the equilibrium of the forces in the tapered die part and of the yield criterion of the material being extruded. Analytical solutions have easily been obtained in the cases that the yielding behavior of the material obeys Tresca or von Mises yield criterion and where the yield stress does not depend on strain or the strain dependence of yield stress is represented in a simple analytical form. The yielding behavior of metallic materials satisfies these conditions.