Abstract: An optimization method for preform die shape in non-isothermal metal forming using plastic finite element method, sensitivity analysis and engineering optimization algorithm is presented. The preform die shape is represented by cubic B-spline. The control points of the B-spline are used as the design variables. By optimizing preform die shape, net-shape forging process can be realized, and flashless final forging with complete die fill and without defect can be obtained. The optimization procedure of preform die shape is given. The sensitivity of nodal velocity and temperature with respect to design variable is developed. Finally, the forming process of an axisymmetric disk as an optimization example is given.

Key words: Finite element method, Preform design, Sensitivity analysis, Shape optimization