Optimization Of Injection Molding Process Parameters For Bicolor Headlamp Covers Of Automobile Headlamps

With the vigorous development of the plastic industry,the automotive industry,which pursues lightweight,has gradually formed a new trend of "replacing steel with plastic",making injection molded parts widely used in the automotive industry.The positioning of automotive injection molded lights has gradually shifted from simple functional parts to important parts that combine appearance and function,and their structural form has gradually shifted from monochromatic transparency to dual color combination,moving towards high-end,high-precision,and highly complex directions.During the dual color injection molding of the lamp shade,there will be quality defects such as excessive warpage and deformation,which directly affect the light transmittance,appearance quality,and assembly accuracy of the lamp.Therefore,improving the molding quality is particularly important.This thesis takes the dual color headlight lampshade of a certain brand of sedan as the research object.In order to reduce the amount of warping deformation and improve its appearance molding quality,preliminary work has been mainly carried out,such as determining the sequence of dual color injection molding,selecting materials,and establishing a hot runner pouring system.Then,six dual color injection molding process parameters are selected as influencing factors,and the amount of warping deformation is used as the quality indicator,Design 50 optimal Latin hypercube experimental schemes for Moldflow simulation,and establish high-precision approximate models based on Kriging interpolation method.By establishing a Kriging approximation model,global influence effects,single factor,and interaction analysis were conducted on the process parameters and warping deformation of dual color injection molding.The causes of warping deformation were further explored from the aspects of melt flow behavior,cooling state,volume shrinkage,residual stress,and mutual constraints between the first and second shots.And analysis shows that the pressure holding stage of the first and second shots has a greater impact on the warping deformation,while the filling stage of the first and second shots has a smaller impact on the warping deformation.Based on the established Kriging approximation model,the adaptive simulated annealing algorithm and multi island genetic algorithm were used to globally optimize the process parameters of dual color injection molding.The results of the two algorithms were verified through simulation experiments,and the simulated warping deformation of the adaptive simulated annealing algorithm was 1.746 mm,with an error of 3.3%;The simulation result of the warping deformation of the multi island genetic algorithm is 1.730 mm,with an error of 2.3%.Compared with the recommended process parameter simulation result of 3.542 mm,there is a significant decrease.Through comparative analysis,it is found that the multi island genetic algorithm is more suitable for optimizing the injection molding process parameters of the dual color lampshade of automotive headlights,improving the warping deformation of the dual color lampshade of automotive headlights.