Numerical design of die land for shape extrusion

In the extrusion of shapes with flat-faced die, the proper design of die land is of critical importance in avoiding the generations of geometry defects. A methodology for the design of die land, which consists of a simulation-adjustment iteration, is proposed. The metal flow in extrusion is simulated by the three dimensional finite element method and the die land is adjusted according to the simulation result. Both the formulae for adjustment of the die land and the criterion for the judgment of proper die land are suggested. The extrusion of an L-section shape is chosen as the computational example and the result is compared with the industrial design.