Material flow analysis and extrusion die modifications for an irregular and multitooth aluminum alloy radiator

Material flow uniformity in a die cavity is the key to extrude sound aluminum alloy radiators. However, it is generally difficult to control material flow due to their geometry features, such as complex cross section, multiple teeth, etc. In this work, for an irregular and multitooth aluminum alloy radiator, the initial extrusion die is firstly designed. Numerical simulation and experimental observation both show that the extruded radiator could not meet the size and shape requirements due to severe twist deformation in the cross section. Then, four different die modifications (resizing the porthole structure, chamfering the mandrel support, adding baffle plates, and adjusting bearing lengths) are taken to improve material flow uniformity during the extrusion process. Through a series of die modifications, the velocity difference in the cross section of the radiator is reduced from 34.9 mm/s with the initial extrusion die to 8.3 mm/s with the modified one. The standard deviation of the velocity field in the cross section decreases from 10.7 to 3.3 mm/s, and the velocity uniformity is improved greatly. With the modified extrusion die, a sound radiator is extruded with the desired size and geometry. Finally, the extrusion die modification rules are summarized for this kind of radiators.