Based On Two Dimensional With Genetic Algorithm (ga) Powder Injection Molding Filling Process Numerical Simulation Research

The powder co-injection molding filling process was analyzed and verified by theory of numerical analysis and experiments by using a FEM/FDM method. A High-precision second unit format was used to solve the pressure field and Genetic Algorithms was used to research the Cross-WLF viscosity model. The multi-peak analysis of the model was achieved by using Genetic Algorithms. Through the analysis of the thickness of core/shell interface, it was determined by experiments and numerical fitting. The melt front was traced by a modified control volume.This paper was composed of five chapters. A brief overview of Powder co-injection molding and significance of the study on the computer simulation of injection molding filling flow and background of numerical solution of powder injection molding was introduced in chapter one.Three mathematical models--the generalized hele-shaw flow model, the two-phase flow model and particle model, which describe the flow of powder co-injection molding were introduced in the second chapter. And three viscosity models--Power-Law model, Cross-Arrhenius viscosity model and Cross-WLF of the melt filling were also included. The viscosity of feed was measured.Chapter Three and Four describe the main results of this paper. The basic principles and mathematical model of genetic algorithms were introduced in chapter three. The advantage of using genetic algorithms to research the Cross-WLF viscosity model was discussed in this chapter. Parameters of viscosity model were fitted.The multi-peak analysis of the model was achieved by using Genetic Algorithms. Studies have shown that genetic algorithm fitting accuracy is better than other algorithms and given the spatial distribution of the different parameters while the Cross-WLF viscosity model obtained the optimal value.In the fourth chapter, Hele-Shaw flow was used for the filling process of PCM, and a mathematical model’and reasonable simplification of filling process were proposed based on the conservation equations abided by continuous medium. And the numerical simulation method of control equations was proposed. The solving of control equations of fields was resolved by FEM/FDM method. A High-precision second unit format was used to solve the pressure field. Through the analysis of the thickness of core/shell interface, it was determined by experiments and numerical fitting. The melt front was traced by a modified control volume. Further more, the numerical simulation program of PCM was developed by mean of Matlab, as a result of movement of skin front and core/skin interface and profile of temperature and pressure fields were obtained. Finally, simulation results were compared with experimental results. The simulated results agree well with the movement of feed’s forefront. With the filling of the feed, the deviation between simulation results and the test results increases. The reason may be that the contraction of injected parts was ignored in the process of numerical simulation.Chapter Five is the summary of the full paper.