Rapid Heat Cycle Injection Molding Simulation And Optimization Of Warpage And Shrinkage Control Process For Automotive Thin-walled Plastic Parts

Rapid Heat Cycle Molding(RHCM)is a special molding technology based on Conventional Injection Molding(CIM).It has the advantages of energy saving,environmental protection and high efficiency,and can largely improve the quality of products.RHCM technology adopts fast and dynamic mold temperature control technology.Compared with CIM injection molding,the process requirements of RHCM technology are more stringent,and the products are more prone to warpage and shrinkage defects.In order to give full play to the molding advantages of RHCM technology and control the molding quality of plastic products,in this paper the process optimization research of warpage and shrinkage defects is focused in RHCM injection molding.On the basis of summarizing the injection principle,shrinkage mark and warpage deformation theory of RHCM technology and CIM process,automobile B-pillar inner panel is taken as an example,and warpage deformation and shrinkage mark index are taken as optimization objectives,the optimal combination scheme of warpage and shrinkage mark of CIM injection and RHCM injection was obtained by Taguchi orthogonal test method,The accuracy of Taguchi test is verified by CAE simulation technology.Finally,the SVM prediction model of RHCM injection molding process parameters and warpage deformation amount and the Bayes prediction model between RHCM injection molding process and shrinkage index were established by using the machine learning algorithm in artificial intelligence technology to train the test data obtained from RHCM injection molding simulation tests.Through the analysis of CIM injection molding and RHCM injection molding orthogonal test method,the significant order of warpage deformation of two kinds of injection molding was obtained.The optimized deformation of CIM injection molding Taguchi test was 0.595 mm,which was 50.3% less than that before optimization(1.197mm);The warpage of Taguchi is 0.7826 mm,which is 79.1% lower than that before optimization(3.743mm).The above orthogonal test results show that the two injection molding can achieve the effect of reducing warpage through optimization.Although the deformation of RHCM is larger than that of CIM(0.7826-0.595)/ 0.595 = 31.5%,the optimization effect of RHCM is obviously better than that of CIM to achieve the effect of controlling warpage.RHCM also has the advantages of reducing injection molding time and improving surface quality(reducing subsequent surface modification process).Machine learning combined with genetic algorithm was used to establish GA-SVM Warpage Optimization Model and GA Bayes shrinkage mark optimization model.The optimal RHCM injection process combination of warpage and shrinkage mark was obtained by optimization calculation.The optimal RHCM injection process combination of warpage and shrinkage mark was input into Moldflow for simulation verification.The warpage prediction error was only 0.2%,and the warpage deformation was reduced by85.1%;The shrinkage index error is only 0.6%,and the shrinkage index is reduced by65.7%.It can be seen that GA-SVM and GA Bayes model can predict and optimize the warpage and shrinkage of RHCM injection molding.