A COMPARISON OF
W. Michaeli,
C. Lettowsky
Institute of Plastics Processing (IKV) at RWTH
Aachen University
Pontstraße 49, 52062 Aachen, Germany
Multi-component
injection moulding has gained enormous importance over the last fifteen years.
This is due to development of more sophisticated products and to the constant
endeavours to cut costs. One new trend – the combination and integration of
well-known processes to a new process – has become more and more important for
some years and it still continues to flourish as recent developments are
showing. The combination of sandwich-injection moulding and
injection-compression moulding is an example for such a process combination.
Conventional sandwich injection moulding enables the production of multilayer
parts with a skin-core-skin structure. By coupling different materials
properties of products can be set in one step systematically. A trend towards
thin-walled parts can be observed in the injection-moulding sector.
Injection-compression moulding offers the opportunity to produce such parts
with improved mechanical properties. The combined process – sandwich
injection-compression moulding – was investigated at IKV. It is divided into a
three-step injection phase and a subsequent compression phase. The result is a
thin-walled, sprueless, sealed, sandwich part. The
combination offers an attractive means of producing sandwich constructions that
exploit the advantages of the two single-processes. The results of a comparison
of sandwich injection moulding and sandwich injection-compression moulding are
discussed in this paper.