Multi-objective Optimization Of Injection Process Parameters Based On Kriging-GA And Mold Design Of Automobile Daytime Running Light Guide

With the continuous improvement of people's quality of life,the requirements for the performance and appearance of products are increasing to improve.It is difficult to development complex products with traditional production methods that rely on experience.Innovation of CAE technology has been continuously promoting by the rapid development of computer technology.In industrial production,the application of CAE technology will effectively predicte defects and improve possible problems,which can simultaneously increase production efficiency and reduce production costs.The automobile daytime light guide is chosen as research object in this paper,the prediction and simulation are carried out with the help of CAE software,the preliminary analysis of the plastic parts and mold design are carried out by using CAD software.The injection molding process parameters are studied by using modern optimization algorithm.The main contents of this paper are as follows.Firstly,the development course of automobile light,the related knowledge of automobile daytime light guide and the shaping technology of automobile light are briefly introduced.The CAE theoretical knowledge of injection molding and common CAE software are discussed.Combining CAD software UG with CAE software Moldflow,the injection molding process is simulated,the shaping characteristics are analyzed,and a set of injection mold is designed with cold runner and hot runner gating system,double pushing plate secondary ejection mechanism and swing rod type pre-reset mechanism.Then,the injection time,mold temperature,melt temperature,packing pressure,packing time and cooling time are selected as design variables,the warpage and volume shrinkage are taken as objective functions,the experimental design was carried out based on the optimal Latin hypercube,and the Kriging model was established.And the effects of process parameters on volume shrinkage and warpage were analyzed.Finally,in order to improve the injection molding quality of automobile daytime light guide,the multi-objective process parameters were optimized based on NCGA and NSGA-II respectively,and a reasonable combination of process parameters was obtained to make the warpage and volume shrinkage meet the production requirements.By comparison,the process parameters combination obtained by the two optimization algorithms are the same,that is,the injection time is 1.2s,the mold temperature is 98?,the melt temperature is 301?,the packing pressure is 65% of the injection pressure,the packing time is 12 s and the cooling time is 20 s.The warpage and volume shrinkage rate obtained by NSGA-II optimization are 1.662 mm and 11.66% respectively,and the warpage and volume shrinkage rate obtained by NCGA optimization are 1.599 mm and 11.58% respectively.Moldflow simulation is used to verify the NCGA optimization results and NSGA-II optimization results,and the relative error is less than 5%.Based on the above optimal process parameters,the actual production verification shows that the NCGA optimization results are closer to the actual production value.Therefore,the NCGA optimization method is more accurate.The above shows that the combination of process parameters obtained by multi-objective optimization is more reasonable.The theory of multi-objective optimization based on genetic algorithm has guiding significance for seeking the best combination of injection process parameters and provide convenience for actual production,which can improve the shaping quality of plastic parts and shorten the product development cycle.