Minimization of the exit profile curvature in non-symmetric T-shaped sections in the extrusion process

In this study, a methodology is presented for minimization of the exit profile curvature of the die in the extrusion process. By using the equations from Chitkara works, a set of non-uniform velocity equations were obtained. Some improvements in these velocity equations concerning the friction effects have been done. The objective functions for definition of the curvature were established according to the material flow distribution in the exit section. By variation of the Bezier coefficients and off-centricity values, the optimum die which yields the minimum exit curvature was designed. To verify the suggested objective functions (deviation criterion), three dies were manufactured by means of CAD/CAM package. Then, the direct extrusion process was simulated physically by plasticine. Comparisons of the exit curvatures showed good results concerning the objective functions in minimization of the profile curvature.