Process combination of hydroforming and injection moulding for the in-situ manufacturing of metal and plastic composite structures
Verfahrenskombination von Innenhochdruck-Umformung (IHU) und spritzgießen zur in-situ-Fertigung von Hybridbauteilen aus Metall und Kunststoff
The Using of lightweight structures is a big trend for reducing fuel consumption and CO² emissions especially in the transport sector. Metal plastic hybrid structures are an efficient solution to use the best material at every place. The current states of the art for the manufacturing of metal plastic composites are three technologies: the insert technology, the outsert technology and the metal plastic hybrid technology. In all technologies the metal parts were produced separately from the plastic parts. The injection moulding process is only used for forming the plastic parts and for joining. This process chains are very long. At the Fraunhofer IWU new process combinations are under development. The aim is a combination of metal forming and injection moulding in one die and one process. One part should be produced with every stroke of the press. In a first step deep drawing, injection molding and media based forming with the plastic melt have been successfully merged in one tool and one process. It was possible to integrate the injection moulding process in a deep drawing machine. In the next step hydroforming with gas and injection molding could be combined successfully. For this process combination the hydroforming process is integrated in an injection moulding press. Different surface structures of the metal pipes, such as sandblasting, knurling and laser structuring, were systematically tested regarding to their properties as an adhesion promoter. The goal is to establish a purely mechanical connection between the hydroformed metal component and the injection moulded component from glass fibre reinforced plastic instead of the previously often used chemical bonding agents, such as Vestamelt. This work was performed within the Federal Cluster of Excellence EXC 1075 ""MERGE Technologies for Multifunctional Lightweight Structures"" and supported by the German Research Foundation (DFG). Financial support is gratefully acknowledged.