Simulation and process validation of an efficient combination of high-pressure die-casting and injection molding to produce metal-polymer-composite parts in one mold

The research objective of this doctoral thesis was the development of a combined process plant (2C-process) to produce metal-polymer-composite parts via high-pressure die-casting (HPDC) followed by overmolding of the casting. For this purpose, an injection unit was integrated into a high-pressure die-casting machine. Apart from the plant-engineering integration of the injection unit, appropriate software interfaces had to be created to enable an automized process. Furthermore, a two-component mold (2C-mold) was designed, whose working principle was based on a rotational molding technique, which is already well-established in mass industry, namely the rotary plate technique. To minimize the number of processing-related disruptive factors, all materials selected for the experiments were sufficiently proven in industry. On the one hand, a conventional hypoeutectic aluminum casting alloy was applied for the HPDC-process. On the other hand, the materials for the injection molding (IM) process were varied by using three polymer compounds based on different semi-crystalline thermoplastics (PPS, PA 6 and PBT) as well as one thermoplastic elastomer based on ester polyurethane (TPU). Basically, the practical experiments were divided into preliminary and main experiments. The preliminary experiments were targeted at the elaboration of an appropriate combination of release agent, surface cleaner, conversion agent and adhesive agent/primer to realize a material-bonded composite adhesion. Since no combination led to an industrially relevant adhesion strength, the 2C-mold design had to be modified, so that a form-locking joining of the composite components could be implemented. In the course of the main experiments, the 2C-process plant layout was prepared to execute the actual feasibility study. Since the first visual inspections of the produced composite parts referred to a successful process flow, further testing methods were used to achieve a more significant analysis. While the quality of the composite parts was checked by 3D-scanning, mechanical processing, measuring microscopy, DSC, TGA, shore A-measurements, density measurements and tensile tests, the 2C-process¿ ecological efficiency was evaluated via recorded energy data. Although the composite parts¿ assessment exhibited potential for improvement, no defects were detected, which would represent any exclusion criteria for the 2C-process and its suitability for industrial applications. Besides, provided that specific conditions are given, the ecological evaluation of the 2C-process showed its practical relevance from this point of view. In addition to the practical feasibility studies, the 2C-process to be validated was analyzed by simulations. At its current status, no software program offered the equivalent simulation of both processes, wherefore two simulation methods (SIGMASOFT and MAGMASOFT) had to be combined with each other for a preferably significant simulation of the 2C-process (2C-simulations). Despite the extensive compatibility of these simulation methods, their combination required an application-oriented solution approach. Referring to the simulative feasibility study to validate the 2C-simulations¿ practical relevance, most results from the thermal as well as from the stress and warpage analyses met the expectations. While the former were double checked by thermographic recordings of the 2C-process, the latter were compared with the investigations of the produced composite parts.