Papers by Author: Qiu Hui Liao

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Authors: Qiu Hui Liao, Xiao Xun Zhang, Qin Chao Ruan
Abstract: The accurate prediction of warpage of injection molded parts is important to achieve successful mold design with high precision. In this study, effects of polymer-filler properties, such as filler aspect ratio (L/D), filler modulus parallel to major axis (E1) and filler modulus perpendicular to major axis (E2), on warpage displacement of automobile door were studied quantitatively by experimental investigation and numerical simulation. The numerical results are in good agreement with the experimental measurements. It is also found that: (1) the thermal displacement decreases as E1 and E2 decrease, (2) the PVT displacement is not influenced by change of L/D, E1 and E2, (3) the orientation effect displacement is neglected small when L/D=1 and E1= E2, and it also increases as L/D and E1/E2 increase.
Authors: Xiao Xun Zhang, Luo Wang, Qiu Hui Liao
Abstract: Polypropylene specimens were made by the injection molding experiments under different processing conditions. The crystallinity of each polypropylene specimen was obtained using the X-ray diffraction method. The effects of the injection molding processes on the crystallinity of polypropylene were revealed: (1) the crystallinity decreases as the melt temperature increases, and the higher the melt temperature, the slower the crystallinity decreases, (2) the crystallinity decreases as the mould temperature increases, and the higher the mould temperature, the faster the crystallinity decreases, (3) the crystallinity increases as the injection speed increases, and the larger the injection speed, the faster the crystallinity increases. By the tensile experiments of the injection molded specimens, it is also found that the crystallinity has a major impact on the mechanical properties of polypropylene. The yield strength and tensile strength of polypropylene specimens increase as the crystallinity increases.
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