Warpage of injection-molded automotive B pillar trim fabricated with ramie fiber-reinforced polypropylene composites

This study investigated the warpage of injection-molded automotive interior component (B pillar trim) fabricated with four types of short ramie fiber (RF) reinforced polypropylene (PP) composites with different fiber percentages, namely, 0RF/PP, 10RF/PP, 20RF/PP, and 30RF/PP. The effects of injection-molding process parameters and the fiber addition on the warpage of the component were investigated through numerical simulation using orthogonal experiment method. The results showed that packing pressure and filling time were the most important factors affecting warpage. And the minimal warpage values of the components made of 0RF/PP, 10RF/PP, 20RF/PP, and 30RF/PP were of 3.632, 3.698, 4.070, and 3.798mm, respectively, at their own specific optimized process parameters. Additionally, fiber addition also plays an important role on the warping deformation of the component. The warpage increased first and then decreased with the increase of fiber addition, and an inflection point occurred at 20wt% fiber addition. This is because the fiber orientation can promote the warping deformation, while the increase of composite's modulus due to the fiber addition can hinder the warping deformation.