The master's thesis includes an analysis of the results of extrusion simulations of hollow profiles or tubes made from the aluminium alloy EN AW-6082. It is well known that, in addition to technological parameters, the quality of the final hollow products—specifically the quality of the longitudinal weld—is also influenced by the design of the porthole die used in the extrusion process of hollow profiles.
The purpose of the master's thesis was to simulate the extrusion process of hollow profiles made from the mentioned alloy using various porthole die designs based on existing constructions and to compare them with simulations based on concepts and designs found in the relevant literature. Based on the simulation results, the goal is to determine which die or die design is most suitable for increasing productivity in production, and to formulate design recommendations for achieving high longitudinal weld quality in the development of future tooling solutions.
For the purposes of the simulation, the CAD models of the tools were established using ANSYS SpaceClaim software, thereby providing the geometric definition of the toolset. The material properties of the EN AW-6082 alloy were derived through the application of the thermodynamic modeling software JmatPro. Subsequently, the extrusion process simulation was carried out employing the QForm Extrusion software package.
The results of the research demonstrated that the newly designed tool “D2” exhibits, based on the outcomes of the simulation, a more favorable predisposition for achieving higher productivity. Consequently, the new tool design was selected for implementation in production. It was further established that a reduced number of ribs leads to lower resistance of the tool itself and, therefore, to a lower maximum press ram pressure P_max. For this reason, a rib count of two to three is recommended, provided that this is feasible from a design perspective. The number of webs governs the velocity distribution, as the ram speed of the press is divided among the individual webs, which enables higher extrusion speeds and increase productivity. The application of a shaped chamber die additionally contributes to an increase in the welding pressure at the joint location, while simultaneously reducing the length of the transverse weld, which positively influences the quality of the longitudinal weld. Finally, it was determined that flat welding chambers tend to generate an excessive volume of dead zones, thereby reducing material yield and negatively affecting the pressure field at the weld interface.
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