Optimization of Bearing Lengths in Aluminum Extrusion Dies

Bearing design plays a key role in producing high quality extruded products. Balancing the flow by adjusting the bearing lengths to eliminate profile distortion is a common practice in the industry. The bearing correction, however, is accomplished by costly trial and error approaches – largely relying on the expertise of die designers. In this paper we present a numerical algorithm to optimize the bearing lengths that produce uniform velocity at the die exit. This is based on a finite element model to solve material flow during extrusion. The solution approach involves iteratively computing velocity, temperature, and strain fields during extrusion and updating the bearing lengths until balanced flow is achieved. Different aspects of bearing design and robustness of this optimization technique are illustrated through a few examples.