Multi-objective Optimization Of Injection Process Parameters And Mold Design Of Tricolor Automotive Fixed Side Taillight Lampshade

With the improvement of production capacity and the popularization of private cars,while satisfying the use performance,the automotive lamps should also meet people's pursuit of highend and high-grade,and therefore multi-color injection molding is more and more widely used in the production of automotive lamps.Due to the difficulty of molding,multi-color injection molding has become a hot research direction of injection molding technology.In this paper,taking tricolor automotive fixed side taillight lampshade—a typical tricolor injection molding part as the research carrier to study the quality control in the molding process.Combined with CAE theory,the product structure optimization,mold design and multi-objective optimization of process parameters are carried out.The specific work and progress were as follows:(1)The injection sequence and materials were determined according to the product structure,and got the good joint surface.Static analysis and topology optimization were carried out for the deformation characteristics of the first plastic part.The warpage of the first shot before optimization was 3.160 mm and the weight was 133.82 g.After optimization,the warpage of the first shot is 2.943 mm and the weight is 129.92 g.It is proved that after optimization the stiffness of the first shot component is improved and the weight is reduced.Then combined with CAE analysis results and mold design theory,a set of fixed side tricolor taillight lampshade injection mold was designed.(2)Then,mold temperature,first shot melt temperature,second shot melt temperature,first shot packing pressure,second shot packing pressure and packing time are taken as design variables,the first shot volume shrinkage,the second shot volume shrinkage and total warpage are selected as the output variable,using the Optimal Latin hypercube to take the test samples,got the experimental data through Moldflow analysis.Establishing approximate models of process parameters and quality indicators based on Kriging interpolation.Then,the influence of process parameter on the volume shrinkage of each part and total warpage was analyzed.(3)Then in order to improve the quality of the tricolor fixed side taillight lampshade,based on the established Kriging model,both the global algorithm PSO algorithm and MIGA were used for multi-objective optimization,and the optimal solutions obtained by the two algorithms were analyzed and compared.It is found that the MIGA has a better global optimization effect,the objective function converged in the late iteration,and the optimal solution was found in the Pareto solution set.(4)The process parameters obtained by the two algorithms are compared with the Moldflow simulation results then found that MIGA optimization has more accurate results that the first shot volume shrinkage is 9.214%,the second shot shrinkage is 6.477%,the total warpage is 1.936 mm,and the corresponding technological parameters combination is: the mold temperature is 50 ?,the melt temperature is 244 ?,the second shot melt temperature is 243 ?,the first shot packing pressure is 42 MPa,the second shot packing pressure is 48 MPa,the packing time is 11 s.(5)Finally,the obtained process parameters were used for production verification,and the products with good quality were obtained.The surface of the part is smooth,without pits and sink marks;the three-dimensional scanner detects that the warpage before optimization is 2.556 mm,and the warpage after optimization is 2.107 mm,which is reduced by 17.8%.The results prove that combining Kriging model and MIGA can provide convenience for the optimization of tricolor injection molding process,and has good practical application value.