A And B Shell Injecton Molding Process Optimization

With the rapid development of plastic industry and the injection molding technology being mature, the required appearance quality and performance of plastic products are more and more high. It is of great significance for the pratical applications by optimizing injection molding process to improve the quality of plastic products. In this paper, the research objects are A and B plastic surface shell with some defects because of original molding process. Therefore, the finite element simulation and experimental method are applied to research double-cativy mold injection molding process and warpage deformation, solving the defects such as scraping hands, dislocation and off-shell caused by flash and warpage deformation in the fitting parts molding process. The main research contents contain the following several aspects:(1) Establishing accurate and reliable finite element model. Based on the original plastic forming process, the finite element model is established and validate the model with the warpage deformation of A and B plastic surface shell for the measure.(2) Runner balance optimization in double-cativy injection molding. The gating system is improved on the basis of pouring balance designing theory and finite element simulation "variable section method". Further, the flash is removed and the warpage deformation is reduced by adjusting runner size and improving melt flowing conditon.(3) Establishing Kriging model between process parameters and warpage, and verifying model accuracy. Experiment is designed by the Latin hypercube sampling for the main process parameters (mold temperature, melt temperature, injection time, cooling time, packing time, packing pressure) affecting warpage deformation. The finite element simulation analysis is used to determine the response value of initial sample group, and approximate function relation between process parameters and warpage value based on Krigring model.(4) The process parameters global optimization based on genetic algorithm. On the basis of Kriging model, the optimum parameters are obtained with genetic algorithm when the warpage deformation is the minimum value, and the forming quality of plastic parts is improved. Finally, the change trend of a single process parameters on the warpage value is studied on the basis of the optimal design.The results show that the filling time imbalance rate is controled in 0.61% and the pressure imbalance rate is controled in 3.87% after runner balance optimization. The biggest warpage is 1.36mm after process optimization, and is reduced 34.8% than before optimization. In addition, injection time has the greatest influence on warpage, and the second is the packing pressure.