كمينه كردن انحناي پروفيل خروجي مقاطع خارج از مركز غيردايروي در فرايند اكستروژن، با استفاده از منحني هاي Bezier

MINIMIZATION OF THE EXIT CURVATURE OF NON-SYMMETRIC SECTIONS IN EXTRUSION PROCESS, USING BEZIER CURVES

In this study, an analytical method is proposed for de termination and minimization of the exit curvature in extrusion dies. The stream lines are determined by us­ing the Bezier formulation. The improved Bezier for­mulation is achieved by adding some parameters to the stream line equations and the non-uniform velocity field is extracted from the improved Bezier formulation. By defining the exit curvature criteria, the die is optimized, according to the Bezier coefficients and eccentricity val­ues. For verification of the proposed procedure, the exit curvature of some selective dies is calculated by using Abaqus FEM Software. The FEM results show good agreement with the proposed procedure. Finally, the extrusion pressure of the dies is calculated, based on the minimum energy consumption criteria, according to the upper-bound method. Then, the estimated pressures, according to the minimum curvature and minimum en­ergy criterion, are compared