| Summary: | 碩士 === 國立高雄應用科技大學 === 機械工程系 === 106 === This study investigated the molding warpage problem of a sewing machine’s upper cover by mold filling analysis. The upper cover is made from two injection products, the thin (upper) cover is 1.5 mm thick and the base is 3.0 mm thick.
The thin(upper) cover is thin and large in size, it is easy to have large deformation in Y direction after demolding. Because of the thin cover warping, it will cause the thin cover to separate from the base even after bonding them together for a long time. The purpose of this study is to find the best processing parameters combination to reduce the warpage of the thin cover thus to solve the separation problem of the two parts by mold filling simulation.
Moldex3D mold filling analysis software and Taguchi experimental method will be used to analyze the influence of the molding parameters on the part warpage in this study. An L9 orthogonal table was selected for this Taguchi experiment which has filling time, holding pressure, mold temperature and melt temperature as the control factors, each control factors have 3 levels in this experiment. According to the results of Taguchi experiment, the optimal average volumetric shrinkage was 0.726%, and the volumetric shrinkage at observation point A point decreased from 1.477% to 0.195%, at point B decreased from 1.417 % to 0.124 %, at point C decreased from 1.979% to 0.845%, and at point D decreased from 2.293% to 1.158%; the optimized displacement was 0.607 mm, the volumetric shrinkage at displacement point A point decreased from 1.138 mm to 0.564 mm, at point B decreased from 1.374 mm to 0.5674 mm, at point C decreased from 1.953 mm to 1.161 mm, and at point D decreased from 2.095 mm to 1.314 mm.
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