Integrative Optimization of injection-molded plastic parts - Multidisciplinary Shape Optimization including process induced properties

The Integrative Approach described in this paper incorporates effects of the part’s manufacturing process (here: injection molding) into a new workflow for optimization of the part performance. The new approach is able to close the gap between process simulation/optimization and mechanical simulation/optimization. New classes of design variables linked to the manufacturing process complicate the workflow of the optimization. The newly introduced optimization discipline “manufacturing simulation” acts as a preprocessing step for all other disciplines while it can simultaneously be seen as a full optimization discipline as well. Shape optimization by morphing is included as well and further complicates the workflow. The paper outlines the necessary changes in the workflow and discusses the influence in different optimization scenarios. In a first example the prototype workflow based on state-of-the-art software packages and newly developed script and interface tools was designed, defined and proved to work. A screening phase as well as an optimization had been done with reasonable results. The part considered in this study is a thermoplastic structure, manufactured by injection molding. The most important process induced changes are based on the anisotropic orientation of short glass fibers in the material during filling. These effects had been taken into account using BASF’s ULTRASIMTM software. Filling simulation as well as warpage simulation and a mechanical impact simulation were used as single optimization disciplines.