Auto Thin Case Injected Plastic Part Tilting Distortion & Manufacturing Process Optimization Research

The process and method of traditional injection molding are all ready consummate which are different from that in thin-wall injection molding. It is much more difficult to fill the cavity because the melt is frozen very quickly when the thickness become smaller. Also, the flow behavior of the polymer melt in thin-wall injection molding is different from that in traditional condition. Many problems are unsolved. Thin-wall plastic parts are very typical ones in auto products in which warp is the main defect and led many final assembly failure. Plastic injection is non-linear and flexible multi-factors manufacturing process. Due to many factors involved, their impacts on the final quality is different. To decrease the defective parts in production, we need to adjust and optimize the factors and obtain one best group data to meet the quality requirement.In this research, a mold of an auto meter face cover is used. The thickness of the cover part are less than 2mm. (In order to consider the influence of thickness, additional machining is made to modify the thickness during the experiments) The research is based on the simulation of Moldflow and the experiments are arranged using method of Taguchi. Range analysis and ANOVA analysis are used in data processing. Effective factors such as injection rate, injection pressure, melt temperature, mold temperature, thickness of the part and injection volume are studied and the interactions between melt temperature and injection rate, injection rate and injection pressure are involved. The results are given in the form of contribution rates.Several process parameters influencing the warp distortion are Synthetics studied. Taking general thin plastic shell as research object, we arrange the combination of process parameters in orthogonal experiment and get result table from numerical simulation of the injection molding. In addition, the influences of various process parameters are analyzed, and the optimized parameter combination is obtained to minimize the warp distortion quantity. A useful conclusion then be reached: several other parameters besides the injection time, such as injection temperature, pack time, also influence warp distortion. Based on auto thin-wall part, we built simulated mathematical model to simulate the plastic injection and obtained the warp data. And measure and analyzed the impact to the thin-wall part of different single factor.