# Effects of Solid Die Types in Complex and Large-Scale Aluminum Profile Extrusion
###### Abstract
The entrance geometry of the cavity was described by a B-spline curve, in which the control points of the curve were modified to achieve optimal geometry with the least deviation of velocity. [PERSON] et al. [25] designed the pocket geometry for complex aluminum profile production using an automatic mesh deformation method. [PERSON] [19] compared the relevant extrusion parameters of the flat-face, and the feeder dies by a 3D FE analysis. They indicated that the metal flow and temperature in extruded products are more evenly distributed when using the die with a feeder. Figure 1: Product defects with an improper extrusion die design. The defects concern with significant bending and twisting of the profile. When the size of the extrusion product is larger than the container diameter, the spread dies can be used [14]. The spread dies are usually equipped with a spreader plate placed in front of the die orifice, which is responsible for adjusting the flow expansion to provide enough material to the die opening. Similar to the pocket die, the spread die creates the necessary pressure to ensure that the transverse weld is maintained during continuous extrusions. The design of the spread die for a large and complex profile is more difficult compared to the traditional flat and pocket dies. The main obstacles for the designer are the entrance geometry and the configuration parameters of the die so that the material can be distributed evenly, and to ensure the die strength. [PERSON] et al. [26] optimised the opening geometry of the spread die for extruding a flat panel profile with a size larger than the container diameter of the extruder. [PERSON] et al. [27] studied the types of inlets for the spread die of solid aluminum profile. They showed that the fan-shaped entrance is consistent with the flat plate profile, with this type of entrance, better extrusion parameters can be achieved in terms of temperature, velocity distribution in extrusion profiles, and die deformation. [PERSON] et al. [28] conducted an experimental extrusion of a simple flat profile. They reported that the extrusion force of the spread die was reduced by about 30% compared to the traditional flat die. From the above literature review, the design parameters of dies and die types play an important role in ensuring product quality and extrusion productivity. The pocket and variable bearing length have been widely used in the die design for solid profiles. However, most studies have focused on simple aluminum profiles. There has been a lack of design guidelines for solid extrusion dies, and an in-depth comparison between the three types of solid extrusion dies for complex geometry profiles has not been reported. In this paper, three types of dies for extruding complex, large-scale aluminum profiles were 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.