Injection Molding Defects Analysis And Moulding Cycle Optimization Based On Moldflow

As a main processing approach for production of plastic products, the injection molding has been widely applied in automobile, electronics, and aviation. However, there are plenty of shortcomings appearing in practice, such as short shot, air traps, weld lines, gas lines and warping deformation etc.. Meanwhile, molding cycle of plastic part is gained more and more significant statue by enterprises with the constant cost rise of labor force. The focal point of relative molding technologist is how to avoid those injection molding defects and how to reduce the molding cycle. At present, the quality of plastic product is mainly controlled by the technologist's practical experience and the repeat of testing mold.The quality defects in molding process can be predicted as well as the tooling structure and injection molding parameters would be optimized by numerical simulation software——Moldflow, where the times of testing and modifying molds will be reduced rapidly. In present work, two typical plastic products in PC case are investigated as the research object, which the injection process is simulated by Moldflow. The cause of quality defects and optimization of molding cycle are focused both by numerical simulation and process test.As for case one, the cause of gas line defect occurred on the surface is analyzed by Moldflow, and the gas lines are eliminated based on the optimized gating system. The tryout results reveal that the product defects can be eliminated totally through the optimized programs, where the cost of products is decreased because of the decreased the raw material.As for case two, based on the numerical simulation results, the variables of connected manners of cooling system, fixed mold, the coolant's temperature of entrance cooling pines in slides or in dynamic model, the melting temperature, normal filling time and the holding pressure in other stages are discussed and investigated by orthogonal experimental design, mean analysis, variance analysis and comprehensive evolutional analysis etc.. The test results show that the optimized process parameters can control the flatness of the injection plastic parts among the range of customer's requirements and optimize the molding cycle.Totally, the research results reveal that the method of numerical simulation combined with process test show an important guiding significance for reducing the surface defects, improving the process parameters and molding cycle. It is shown that the results of simulation and process test are consistent.