Simplified production of metal/plastic parts
In the “Medimold” research project, Simcon worked with research partners to develop a single-stage production process for metal/plastic hybrids. Metal/plastic hybrids are used for printed-board circuit tracks, for example. The new process reduces setup and assembly times for production as well as cutting back on material consumption and the number of work stages required.
The intelligent combination of plastics and metal in a hybrid part keeps the weight of the part down to a minimum, and producers also save costs, since no finishing work is required and single-stage processes are possible. To date, metal parts produced in a separate process beforehand have been overmolded to form hybrid parts.
The “Medimold” research project has now gone one step further: Simcon, the experts for injection molding, the Foundry Institute of RWTH Aachen University and the Kunststoff-Institut Lüdenscheid have developed a faster and more cost-efficient single-stage process for hybrid part production together with additional partners from industry (Krauss Maffei, Ravi and many more). This process involves the metal conductor being injected onto the plastic part in one and the same mold. The project is being funded by the Federal Ministry for Economic Affairs and Energy.
“This single-stage, two-component process marks new territory for all the project partners”, says Max Mades, project manager at Simcon. “In participating in this project, we remain right at the forefront in the development of new processes.”
For the research project, the partners developed a special injection mold with a metal injection unit. In selecting the materials, the team took recyclability into account in addition to the thermal and electric properties. A tin-based alloy was selected for the metal part and, for the plastic part, the partners opted for both thermoplastics and thermosets.
In a large number of tests, the research partners determined the interactions between the metal and plastic, together with the optimum process parameters. Simcon supported the project with extensive simulations and contributed its expertise in the field of plastics processing. The results show that the single-stage process has a high potential in terms of cycle time, production efficiency and machine utilization.
The investigations also showed that the forces of inertia are a key factor. “With plastic melts, the forces of inertia can be neglected on account of the high viscosity”, Mades explains. “The situation is different with metals. Cadmould can now make allowance for this phenomenon and simulate molten metals too.” This pioneering work will also benefit Simcon customers: as of October 2019, Cadmould 3D-F will be available in Version 12 – including the extended functionality for molten metals for the first time.