Process -Structure Interaction for Injection Molded Plastics Parts

During injection molding the mechanical properties of the molded part itself as well as thermal and mechanical loads on the mold or inserts are induced. In the scope of this investigation a procedure is described how to consider these effects in terms of process-structure interaction. The thermo-rheological conditions during the molding process lead to specific mechanical and thermal loads on all parts that are in contact with the melt, which are the cavity walls or surfaces of inserted parts. These loads can be critical for the performance of the part or the mold. Effects that might lead to part or mold failure can be e.g. core shifts, plastic deformations of cores and inserts or over-critical heating of heat-sensitive electronical inserts. On the other hand the mechanical properties of the molded part itself are build during the molding process. Especially in the case of short-fiber-reinforced plastics the flow conditions induce a locally varying fiber orientation distribution within the molded part which in turn leads to anisotropic part behavior. Since short-fiber-reinforced plastics often are used often for application where high cyclic loads occur frequently, especially the consideration of the anisotropy onto the fatigue behavior of such parts is essential. The developed procedure shows how to consider the anisotropic mechanical behavior of injection molded short-fiber-reinforced plastics parts in FE analysis as well as how to simulate thermo-mechanical loads due to the molding process on the mold or inserted parts. It is shown how the existing information, which is provided by injection molding simulation software, can be processed and transferred into mechanical simulation models in order to consider these effects.

The Author

Dr. Wolfgang Korte
PART Engineering GmbH
51429 Köln, Germany

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