Increasing customer requirements for quality and productivity in extruding aluminum products has led to the development of different types of extrusion dies. In this study, three different types of dies, including traditional flat die, pocket die and spread die were designed to extrude complex and large-scale solid profiles. The design parameters for these dies were used from actual extrusion experience. The results obtained from steady-state simulation such as velocity, temperature, extrusion force, and die deformation were used to assess the advantages and disadvantages of the dies. Transient simulations were performed to analyze the evolution of transverse weld in the pocket and spread dies. The effects of ram speeds on the related extrusion parameters were also investigated. The research results provide useful guides for designers and engineers in selecting these types of extrusion dies. parameters of extrusion process can be obtained such as extrusion velocity, product temperature, die deformation, die stress, welding seam etc. [10][11][12]. studied. To balance the metal flow in the extrusion product, the dies were designed with a 3D model using practical experience parameters. After that, numerical simulations of extrusion were conducted by HyperXtrude 2017 software (Altair Engineering, Inc., Michigan, USA) with the Arbitrary Lagrangian-Eulerian (ALE) algorithm. The steady-state extrusion parameters, such as extrusion force, velocity, temperature, and die deformation, were investigated. The transient simulation is utilized to explore the evolution of transverse weld in the billet-to-billet extrusion process of the pocket, and the spread dies. Finally, the effects of ram speeds on the related extrusion parameters were examined. The advantages and drawbacks of these die types are analyzed and evaluated based on the obtained parameters from simulations.

In this study, porthole die used for extrusion of a solid heatsink profile with wall thickness variation ratio up to 15.3 was designed using finite element (FE) simulations. To improve the flow balance in the die, a design approach was introduced to find the appropriate die structure, which includes the porthole and pocket geometry correction, the bearing length adjustment, and the port bridge structure modification. Using the proposed die, the predicted velocity relative difference (VRD) and the maximum velocity difference (ΔV) of extrudate were significantly lower than those of an initial die, which was preliminarily designed based on general design experiences. The required extrusion force and the residual stress in the product were also reduced significantly. Then, the effects of the port bridge structure and welding chamber height on the behavior of the metal flow in the die were investigated. To verify the proposed die design, experimental extrusions were conducted on a 930-ton extruder. The experiment results showed that the extruded product fulfilled the requirements for dimensional tolerances. The design approach presented in this paper can be useful for practical implementation of die design when extruding similar solid heatsink profiles with large wall thickness variation.

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