The Optimization Of Runner System And Process Parameters Of The Mobile Phone Shell’s Injection Molding

Injection molding is the main method of plastic processing. In actual production, as the injection molding process parameters directly determine the flowing, filling and cooling state in the corresponding mold cavity of the melt, and have great influence on the major technical indexes of injection molded parts, such as production cycle, molding quality and injection cost, etc. Therefore, the final quality of the injection molding product can be improved by changing molding process parameters. But in the injection molding process of product, various process parameters would be interactive and change over time, which would cause different influence on the final quality of the injection molding product and make injection molding be a complex process with high non-linear, time variant and multiple parameters action. Therefore, it has very important practical significance for improving the final quality of the injection molding product and reducing the cost of injection molding to use the optimizational injection molding process parameters.In this paper, one plastic mobile phone shell was studied. It’s runner system was optimized. The sink mark index and warpage was used as the optimization indexes. The purpose of improving the product molding quality was achieved by using Taguchi method, range analysis, variance analysis and comprehensive balance method, and combining with Moldflow simulation experiment to optimize the injection molding process parameters.Firstly, related softwares were used to establish the CAE numerical analysis model of mobile phone shell, mainly including mesh division and repair, selection of molding material, creation of runner and cooling systems with guide, etc. Then the CAE model was numerically simulated by using the default parameters in Moldflow software. The conclusion that the runner system need to be optimized was put forward after analyzing simulation result.Secondly, two improvement solutions were put forward for the runner system of the mobile phone shell. The final CAE analysis model was determined by comparing and analyzing simulation results of different solutions. The feasible range of molding process parameters and recommended injection molding process parameters by Moldflow software were get through molding window analysis. By using the recommended parameters to conduct numerical simulation, the feasibility of the built CAE model was verified.Once more, according to the testing program designed by orthogonal test, the sink mark index and warpage of plastic mobile phone shell in injection molding were simulated with Moldflow software. Through the range analysis and variance analysis of the test result, the primary and secondary and significant degree that each experimental factor influenced the single quality indicator, as well as the optimal process parameter combination of single quality indicator were obtained.Finally, four possible global optimal process parameter combinations were obtained by using comprehensive balance method. The final optimal process parameter combination was determined through simulation experiment. The sink mark index and the warpage of the mobile phone shell were both minimum by using this combination, for 0.8197% and 0.2062 mm respectively, and the optimal effect is remarkable. Based on the obtained global optimal process parameter, the injection molding test of mobile phone shell was conducted. The results showed that the product achieved the quality requirement completely, which proved the reliability of the CAE simulation result.The study showed that the research method was feasible and effective, which combined analysis software Moldflow, Taguchi method, data processing method and comprehensive balance method to optimize the process parameters of injection molded parts.