Multi-objective Optimization Of Injection Molding Process For Dual-color Automotive Taillight Fixed Side Lamp Covers

Thanks to the continuous development of technology and productivity,China’s car ownership reached 395 million by the end of 2021,the automotive industry’s requirements for product appearance and quality have been increasing,and Plastic products have become the primary choice for most automotive parts under the general trend of continuous pursuit of lightweight.In this paper,taking the fixed-side two-color lampshade of automobile taillight as the research object,and make a series of exploration to improve the surface quality and reduce the deformation of the product.The first step is to determine the reasonable molding sequence and material selection based on the structural characteristics of the product,and then to design a complete set of molds by combining the CAE analysis results of the pouring system,molding structure,ejector system and cooling system.After that,the first shot volume shrinkage,second shot volume shrinkage and total warpage were used as quality indicators,and the first shot melt temperature,second shot melt temperature,mold temperature,first shot holding pressure,second shot holding pressure and holding time were used as design variables for optimal Latin hypercube test design.60 sets of tests were designed and simulated,and a high precision response surface model was established based on the test results.A high precision response surface model was established based on the test results.Based on the obtained response surface model,the influence of each process parameter on the quality index was analyzed.Finally,based on the obtained response surface model,the optimal molding process parameters were obtained by using isight software for multi-objective optimization:first shot melt temperature 240.03°C,second shot melt temperature 245.65°C,mold temperature 73.41°C,first shot holding pressure 78.42 MPa,second shot holding pressure 80 MPa,and holding time 10.36 s.Moldflow software was used to simulate the obtained optimal process parameter combinations,and the simulation results were again verified to be close to the predicted results,and the results showed that the established response surface fitting equations were highly accurate.The optimal process parameter combination was applied to the actual production,and a product with good surface quality and low warpage volume was obtained.The optimized products showed an 8.2% reduction in maximum volume shrinkage for the first shot,a 3.4% reduction in maximum volume shrinkage for the second shot,and a 20.35%reduction in maximum warpage.