Numerical Simulation And Multi-objective Optimization Of Warping Deformation Of Two-color Flat Long Plastic Parts

In recent years,plastic materials have been widely used in various industries,and the molding process of polymer materials has been paid great attention to as an important field of material processing.With the development trend of automotive lightweight industry,the application proportion of plastic materials in auto parts is gradually increasing,among which multicolor plastic products have become an important research direction of injection molding technology because of the technical difficulty of its molding.In this paper,the typical two-color flat long plastic part,the two-color high brake lamp lampshade,is taken as the research object,and it is pointed out that warping deformation is the main defect of the two-color flat long plastic parts.The Polymer Rheological theory involved in plastic melt molding and the numerical simulation theory in the molding process of two-color plastic parts are introduced.Finally,the optimization method for warping deformation of two-color flat long plastic parts was determined,which was optimized from four aspects: two-color material selection,product structure,mold structure and injection molding process parameters.First of all,the selection of materials,product structure optimization and mold structure optimization are carried out to prepare for the better combination of process parameters in the simulation environment and the better product quality in the practical environment.Then the experimental scheme is designed to optimize the process parameters.The optimization of process parameters is divided into two steps: one is the design center composite test,the other is the ASA adaptive simulated annealing for global optimization.The central composite test is carried out under the condition of fixing the first shooting parameters and adjusting the second shooting parameters.The design variables selected in the experiment are the mold temperature,melt temperature,holding time and holding pressure of the second injection molding,and there are two response targets,namely,the warping deformation of the two-color lampshade and the shrinkage of the second injection volume.The response surface model can be used to analyze the influence of single factor and interactive factor on the two targets.Then,based on the response surface model,the global optimization method of ASA adaptive simulated annealing is used to optimize the process parameters of two-color lampshade injection molding.The optimal combination of process parameters for warping deformation and second injection volume shrinkage is obtained,that is,the mold temperature is 100 ?,the melt temperature is 210 ?,the holding pressure is 55 MPa,and the holding time is 17.6 s.The injection molding simulation is carried out by inputting the above optimal process parameters in Moldflow software.The experimental results show that the simulation results are not significantly different from the predicted values of the algorithm and are better than the predicted values.It is fully proved that the adaptive simulated annealing global optimization algorithm based on response surface model is reliable for multi-objective optimization.The two-color lampshade with good quality is verified by using this set of optimal parameter combination,which effectively shows that the ASA adaptive simulated annealing algorithm based on response surface model can reduce the warpage deformation of two-color flat long plastic parts and improve the quality of the product.