Entwicklung eines kombinierten Druck- und Spritzgießprozesses zur Herstellung von Metall-Kunststoff-Hybridbauteilen auf einer Mehrkomponentendruckgießmaschine

Messer, Patrick; Bührig-Polaczek, Andreas (Thesis advisor); Fehlbier, Martin (Thesis advisor)

Aachen : Gießerei-Institut der RWTH Aachen (2022)
Book, Dissertation / PhD Thesis

In: Ergebnisse aus Forschung und Entwicklung 33
Page(s)/Article-Nr.: 1 Online-Ressource : Illustrationen, Diagramme

Dissertation, Rheinisch-Westfälische Technische Hochschule Aachen, 2022

Abstract

Despite clear differences in the processing temperatures of the materials, die casting and injection molding have many parallels and similarities. Hybrid components are becoming increasingly important, although the associated long process chains, with many intermediate and preparatory steps, are complex and therefore cost-intensive. It thus makes sense to link the two processes directly within one compact manufacturing plant. The development of Multi-Component High Pressure Die Casting (M-HPDC), i.e. the combination of a die casting machine and an injection molding machine towards one manufacturing plant, may close this gap. The key focus of this work is the identification of influencing variables on the bond strength formation as well as the linking of a machine technology, accompanied by the development of a casting die for the production of composite specimen. The results are used to develop a fundamental understanding of the processes involved in this new technology. By means of isothermal process control, it is now possible for the first time in M-HPDC to manufacture specimen reproducibly which show an average shear tensile strength of 3.9 MPa in mechanical testing, accompanied by a very low standard deviation (0.24 MPa) and therefore very good repeatability. Nevertheless, it should be mentioned that there is still considerable potential for improvement in terms of the level of strength which can be achieved. The maximum die temperature in the joining area which can be achieved by means of isothermality (approx. 205°C on the metal side, approx. 150°C on the plastic side) is significantly below the processing temperature of the plastic used. However, the limiting factor towards higher temperatures is the lack of demoldability of the plastic at higher temperatures, whereby the fundamental dilemma (high joining temperatures and low demolding temperatures at the same time) cannot be solved with isothermal process control. To increase the composite strength by raising the die temperature during the joining process reliable variothermal process control is required. In this way, a sufficiently low demolding temperature can still be ensured at higher joining temperatures. The results obtained in the practical tests are used for the conception and design of a further cavity insert (Hybrid III.1). This die insert is designed for purely fluid-based variothermal process control. By arranging the temperature control very close to the cavity it is possible to minimize the mass which needs to be tempered dynamically. With this cavity insert, restrictions of conventional die manufacturing can be circumvented, as the insert is designed for additive manufacturing. The Hybrid III.1 cavity insert combines the determined results within one die insert in which high joining temperatures can be realized without electrical heating components in the die, but at the same time the process heat can be dissipated at short notice for demolding by means of a "cold" temperature control channel which is very close to the cavity and which can be controlled cyclically. The most recent simulations with Hybrid III.1 give reason to suspect that precisely these dynamics can be achieved via this additively manufactured insert and that a further increase in composite strength can be expected in a process-safe manner.

Institutions

• Division of Materials Science and Engineering [520000]
• Chair for Foundry Science and Foundry Institute [526110]