Optimization of die design for thin-walled flat multi-port tube with the aid of finite element simulation

Abstract

Abstract Die design plays a critical role in aluminum alloy profile production, which directly influences the quality of the final products and the service life of the die. In the present study, a porthole die for a multi-hole extrusion process of a thin-walled flat multi-port tube is designed and optimized through numerical simulations. The simulation results show that with the original die, the extruded tube has a non-uniform velocity distribution in its cross-section and bends outward when exiting the die orifice. Meanwhile, a severe stress concentration in the mandrel teeth causes the premature failure of the die, and an uneven deflection of the mandrel teeth and bearing causes the arc-shaped wall thickness of the tube to exceed the tolerance level, which is validated by corresponding extrusion experiments. To solve these problems, two periods of die structure modifications are proposed, and their extrusion processes are simulated. The optimized die is confirmed to exhibit better performance than the original one in terms of lowered maximum die stress, increased bearing pressure, and decreased distortion of the final products. The results of the extrusion experiments indicate that, with the optimized die, a highly qualified tube with good appearance, desired dimensional accuracy, fine-grained microstructure, and high-pressure bearing capacity is manufactured successfully, and the die failure is delayed effectively.