Numerical flow analysis on warpage of film insert molded parts with fiber reinforced polymer substrate

Non-uniform temperature distribution is developed in the thickness direction of the film insert molded (FIM) product during filling and cooling stages due to retardation of the heat transfer through the solid film. Since the non-uniform temperature distribution causes non-uniform shrinkage of the product after ejection and warpage is generated by the non-uniform shrinkage, warpage of the FIM specimen is larger than that of the injection molded specimen. A new mold design was suggested in this study in order to prevent warpage of FIM specimens. Warpage of FIM specimens obtained by using the new mold was smaller than that of FIM specimens obtained by using the conventional mold. Fiber reinforced polymer resins were also used as the substrate to prepare the FIM specimens. Warpage of the FIM specimens with the fiber composite substrate was reduced with increasing the fiber loadings. Warpage of the FIM specimens with carbon fiber (CF) reinforced PC (polycarbonate)/ABS (acrylonitrile-butadiene-styrene) blend was predicted by considering anisotropic material properties such as fiber orientation, thermal expansion coefficient, Poisson's ratio, and elastic modulus.