Genuine metal surfaces on plastic

The company Faurecia Angell-Demmel GmbH with headquarters in Germany rank among the leading suppliers of real-metal decorations which are primarily used in the automotive industry. In cooperation with Netstal-Maschinen AG, the Swiss manufacturer of injection moulding machines, one of the most complex systems has been developed and implemented for the production of operating keys for motor cars.

Within a very short time Faurecia Angell-Demmel have become the market leader for real-metal applications in the automotive sector. Central for this feat is the company's personnel: "We have become what we are thanks to the persons who work for us. In other words: At Faurecia Angell-Demmel you find personalities who devote themselves with their entire professional knowledge, their passion and intuition to one thing alone: Your success."

Be it an operating element, a decorative part, a switch or other device, Faurecia Angell-Demmel offers impressive, powerful solutions in real metal. Taking new approaches, creating values, improving the economic efficiency all along the process chain: Faurecia Angell-Demmel make products yet more attractive with a high-grade real-metal surface design. It takes competent partners to achieve this.

Netstal-Maschinen AG in Switzerland was contacted for first tests in 2005. The task was to operate a complex integral tool which cuts and forms strips of sheet metal, punches symbols in them and back-moulds them directly with up to three plastic components. Decisive in the whole project were the basic characteristics for which Netstal is well known, e.g. precision in combination with a rugged execution of the machine, process stability and flexibility in the programming of the machine control.

After a considerable development period, three Netstal moulding machines are now in production with the forming and direct back-moulding process for which Faurecia Angell-Demmel have lodged a patent application. Two of the machines are engaged in 3-component moulding and one in 2-component moulding. A solution had to be found which allows to process up to 3 suitably matched plastic materials (as regards bonding, mechanical strength, dimensional stability and optical properties) together with strips of aluminium in one tool. One to two of the plastic components additionally assume a light conducting function. A safe and firm bond between plastic and metal is also a must, of course. Strict demands imposed on car-interior operating elements exposed to temperatures from -40°C to +90°C had to be met, and this with a material-authentic surface and in an outstanding optical quality. Add to this a complex metal forming and punching process in combination with multi-component injection moulding, i.e. entirely different processes to be carried out in one and the same tool.

Why the decision in favour of Netstal? The intensive application-technical consultancy and support combined with solution-oriented mechanical engineering were the decisive factors. Faurecia Angell-Demmel attached much importance also to the high process reproducibility in combination with a rugged and precise mechanical execution of the machines. The ability to flexibly programme the machine control sequence was a must to cope with the complex operation sequences. Up to six mould auxiliary controls and five pneumatic stages are used for the process sequence, and this in combination with the three injection units. The multitude of variants didn't confront Netstal and its control with any problems.

In the automotive and many other industries, ever higher demands are imposed on the applied materials as regards optics, haptic and functions. These challenges spur on to a constant further development of the techniques and processes. Thanks to the optimization of the back-moulding method one can now produce backlit switches which leave absolutely nothing to be desired when it comes to optics and haptic. Switches with relieved symbols right to filigree special characters, in particular, can be realized with sharp contours and full material authenticity.

All function symbols are backlit and if necessary sealed light-tight against search light elements. After the sheet metal has been cut, formed, symbol-punched and back-moulded with the actual body of the key housing in the injection mould, up to two different optical waveguide colours for search and function light can be moulded on in the next working steps.

The 3-component back-moulding process enables the production of complete switch panels featuring a harmonic real-metal surface. Switch identification is also in the form of backlit symbols which are punched out without connecting links to the relieved elements. Depending on the application, an ambient illumination or different day and night designs are conceivable. The technology, by the way, is also applicable to decorative parts where symbols, graphic characters or function indications can be integrated.

The rapidly increasing demand for such real-metal applications confirms the success and shows clearly that even highly complex processes reach series maturity if strong partners join forces. Faurecia Angell-Demmel and Netstal cooperated in building up such a partnership in which the combined know-how and experience eventually result in extremely appealing and functional components.