Due to the high complexity of the foaming technology, the relationship between processing and final properties of parts produced is not completely understood. Investigating the causality chain Processing–Morphology–Properties is of great importance, especially for the automotive industry, in order to be able to tailor the mechanical properties of foamed parts. This article examines and qualifies the effects of seven process parameters (melt/mold temperature, degree of foaming, injection speed, delay time, gas content, and back pressure) on biaxial bending and flexural behavior—the predominant deformation mechanisms in interior automotive applications—of foamed plaques, using the MuCell process. The results clearly show that three major factors (mold temperature, degree of foaming, and delay time) have significant impact on the mechanical properties of the foamed parts. For a clear understanding of these interactions, computed tomography scans of certain plaques are correlated to process parameters and mechanical performance. This article should forge a bridge between production and performance. © 2018 The Authors. Journal of Applied Polymer Science published by Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019, 136, 47275.

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The importance of foam injection molded components in industrial applications increases, above all driven by sustainability concerns. In practice, their applicability almost exclusively depends on their mechanical behavior, which is still difficult to predict based on their microstructure. This work aims to present an approach based upon phenomenological observations. From a processing perspective, the objective is to describe the direct processing‐properties‐relationship. Therefore, this work focuses on the effects of different processing parameters on selected final mechanical properties of foam injection molded components using glass fiber‐reinforced polypropylene. A full factorial, central composite design allows for the detection of nonlinear effects, the application of response surface methodology, and the creation of contour plots. Considering three important process parameters (mold temperature, degree of foaming, delay time) and—for the automotive industry—highly important mechanical properties in bi‐ and uniaxial bending, the results show a detailed picture of individual dependences, but also two‐dimensional interactions between the different process parameters. Improvements of more than 140% in absorbed energy and flexural stiffness were obtained at constant part weight. Modulus and strength were increased by 37 and 44%, respectively.

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