logo

Mercedes puts new pressure on powertrain

By: David Vink
EUROPEAN PLASTICS NEWS

October 15, 2013

NEUSS, GERMANY — A front-end module carrier made for the Mercedes-Benz B-Class car with a new internal high-pressure forming (IHF) polymer/metal hybrid process has won a grand innovation award from the SPE Central Europe division.

The Society of Plastics Engineers division presented the award Oct. 14 during its automotive awards night in Neuss, near Düsseldorf.

As the leading application in the powertrains category, the application also involves three companies exhibiting at K 2013: nylon producer Lanxess Deutschland GmbH (Hall 6/C76), Engel Austria GmbH (Hall 15/B42/C8) and Evonik Industries AG (Hall 6/B28). Christian Carl Siebenwurst GmbH & Co. developed and produced the mold for the part.

Swen Malkus, product and project development manager at the Mercedes-Benz plant in Hamburg, talked about the application in March at the Association of German Engineers (VDI) automotive conference in Mannheim, Germany.

Malkus said the process combines high-pressure forming of closed tube-shaped aluminum sections with injection overmolding in a molding tool. Mercedes-Benz uses IHF at its lightweight-construction center in Hamburg to produce the front-end module carriers of the 2012 model-year compact A- and B-Class cars, as well as the instrument panel carrier of the Mercedes SL, Malkus said.

Aside from saving weight, the process offers large-series repeatable production with short cycle times, resulting in highly functionally integrated lightweight parts with structural crash integrity.

In the IHF process, a "pull-press" extruded hollow aluminum profile is bent and embossed in a computer numerically controlled process, before passing automatically into an injection molding tool. The profile has a gap between it and the mold-cavity walls, but with the mold closed, IHF fluid fills the profile interior. Its high pressure expands the profile so it forms a final precise shape against the mold cavity. Fluid pressure is maintained during overmolding of the expanded profile, preventing tube collapse under injection pressure.

Rudolf Fernengel, chairman of SPE Central Europe, stressed the ability of the fluid-filled aluminum pipe to withstand 400-800 bar injection molding pressure.

Fernegel formerly worked for BMW, and currently runs Ingenieurbüro für Kunststofttechnik, a plastics consultancy in Schweitenkirchen, Germany.

Lanxess displayed the A- and B-Class front-end module carrier at the VDI conference, identifying it as molded with a grade of Durethan that it said was a pseudo-plastic, shear thinning, easy-flow glass-fiber-reinforced nylon 6.