Research On Numerical Simulation Of Mould Filling Process Of Lost Foam Casting

The lost foam casting (LFC) technique is taken as the green engineering of foundry industry for the 21st century. It's one prosperous technique of the exact shape of casting process. Because of the decomposability of polystyrene pattern and the reaction with the molten metal during the lost foam casting process, the fluid field, the temperature field and the capability of filling are different from the conventional casting process. Casting defects will appear and this will hold up the further development and application of this technique. Using the simulation techniques, the mould filling process and the influence of many facts can be studied qualitatively, without the bound of the experimental conditions. It can also forecast the casting defects. In this paper, the CAE system of the LFC was developed based on the characteristics of the mould filling process, using the numerical techniques. The mould filling process was simplified based on the phenomena during the LFC. The metal front advance model was developed by analyzing the existing moulds, using the gas pressure between the metal front and the foam as one of the boundary conditions to calculate the metal front. A numerical model is developed to simulate the lost foam casting process,using the finite difference method to solve the governing equations. The cooled metal front and the radiation of the metal were considered to be the boundary conditions. The foundry CAE system of the LFC has been developed combining with the real product. Comparing the simulation result of the LFC with that of the conventional casting process, the characteristics of the LFC have been validated. The CAE system can simulate the metal front advance and the temperature distribution during the mould filling process. It can also control the casting quality effectively.