In-Mould-Forming as an efficient process for the production of steering column-connection hybrid structure
from: Thomas Müller & Ahamd Al-Sehyyab, Institute of Polymer Technology (LKT)
The AVK-Innovation Prize, University Category has been awarded to the Institute of Polymer Technology (LKT), University of Erlangen-Nuremberg within the Composites Night of the 10. Composite Europe Fair on 05. Nov. 2007.
Under the grant of SFB-396 and the finical support by the Deutsche Forschungsgemeinschaft (DFG), a new innovative manufacturing technique (In-Mould-Forming, IMF) has been developed at the institute of polymer technology (LKT). Using this new technique, it was possible to manufacture a fibre-reinforced hybrid structure in a series production scale. The innovation of this new technique is the integrated forming of a pre-heated thermoplastic-based insert directly in the injection moulding machine as well as the overmoulding of short glass fibre-reinforced thermoplastic ribs at the same production cycle.
In addition to the support of the Deutsche Forschungsgemeinschaft, the presented new technique has been developed within a cooperation between the Institute of Polymer Technology and three project partners from the industry and research institutes (Siebenwurst Modell- und Formbau GmbH & Co. KG, Dietfurt/Altmühl, www.siebenwurst.com, DST Draexilmaier Systemtechnik GmbH, Vilsbiburg, www.draexlmaier.de) and Neue Materialien Fürth GmbH (http://www.nmfgmbh.de). The main objective of this cooperation was the developing and manufacturing of a demonstrator part which can be transferred into the automotive applications. A steering column connection has been manufactured after conducting detailed modelling and experimental investigations.
Hybrid structures have been produced so far in batch assembly processes which have a disadvantage of the additional process step for the joining of the different components. These structures have been produced through long manufacturing cycle (pre-heating, pre-forming, trimming, pre-placing and injection moulding). This long process chain has been shortened through the new feasible and robust In-Mould-Forming technique. By IMF, it is possible to form the pre-heated thermoplastic-based fibre-reinforced fabric directly in the mould of the injection moulding machine and in the same processing cycle. The short- or long fibre-reinforced thermoplastic is being moulded over the formed sheet in a form of strengthening ribs. The produced part presents a light-weight hybrid structure which combines the positive properties of both components.
The realisation of the new IMF-technique opened a wide range of possible applications for the manufacturing of high-performance parts such as in motor sports, medical applications, aviation and space technology. In these applications, the light-weight performance has a key role in the development of the load-bearing structures. Weight-reduction with maintained mechanical properties is possible through the optimization of the structural design. The optimization is achieved mainly through the utilization of the an-isotropic material properties and the local strengthening as well as the constructive design of the ribs geometry. Additionally, it is possible to integrate other special moulding processes with the In-Mould-Forming process, such as Foaming process especially in case of sandwich structures or In-Mould-Decoration IMD process for the production of high quality surfaces.