Pre-processing And Post-processing Technology For Numerical Simulation Of Low Pressure Casting

The foundry industry which plays a vital role in the development of national economic, is an important part of the manufacturing industry. The study of casting process computer numerical simulation is valuable to the development of Chinese foundry industry, and it's a trend in the future.In the numerical simulation of casting process, the pre-processing module, which is responsible for importing models and meshing, provides the required grid information to filling and solidification operator. It affects the calculation speed and accuracy of the casting process simulation software, so it is the foundation of the numerical simulation. Post-processing module, which used intuitive image to display the result data, is basis for the prediction of casting defects and process optimization. Therefore, pre-processing and post-processing module in the numerical simulation of casting process, has an extremely important position. This article is committed to research pre-processing and post-processing module in the numerical simulation software of casting process. With Visual C++as a platform, OpenGL3D image processing technology, and the relevant program to develop a pre-processing and post-processing software which are based on the STL file format.In the research of pre-processing module, the traditional mesh was improved, and the STL-based finite difference mesh generation program would achieve the rapid subdivision of casting grid. Using OpenGL to realize the translation, rotation and scaling transformation, so that it would be easy for users to observe the casting. Some special circumstances, like empty encountered in the meshing process, was repaired by the principle of the polygon linked list; by using the shaking method to avoid singular point, which is the vertex of the polygon, to achieve the ideal.In the research of post-processing module, the visualization of simulation data is achieved by OpenGL graphics technology. The meshing result is read and displayed, so that the user can observe the outer contour of castings, rotation and cutting. The casting simulation is showed out truly by the cooling curve and temperature field color map. In addition, the software interface, which is more friendly and convenient, is further improved and extended. Finally, the pre-processing and post-processing module software has been applied to motorcycle calipers and air conditioner shell castings, which have been put into actual production, and the simulation results compared with the mature CAE software. The results confirm that the pre-processing and post-processing module is practical and effective.