Through the analysis of the problems in the actual production of the original lost foam casting process and the ProCAST simulation results, it is considered that the stepped gating system in the original lost foam casting process does not achieve the expected design effect. At the same time, the original lost foam casting process adopts internal pressure self feeding and sprue feeding, but the feeding effect is not ideal, Shrinkage porosity and shrinkage cavity appear on the side surface and large rotating surface of lost foam castings. Therefore, it is necessary to design a gating system conducive to feeding. Considering that the top injection gating system can make the metal liquid solidify directionally from the lower part of the mold, and the feeding effect is good, combined with the production practice, the new scheme adopts the top injection gating system, circular riser feeding, one riser feeding and two lost foam castings.
Combined with the production status and simulation analysis results of the original lost foam casting process, the problems of the original process were improved. The self feeding capacity of the original lost foam casting process and the feeding of the gating system can not meet the use requirements, so the riser should be designed with the design. After analysis, the cylindrical concealed riser is generally selected, with HR of 90mm and Dr of 60mm. Then the gating system is designed, and finally the top injection gating system is selected. The yield of the new process is 67%.
The three-dimensional modeling and meshing of the new process are carried out by proe software, and then the lost foam casting process of the new process is simulated and analyzed by ProCAST software. Through the simulation and analysis of the filling process of the new process, it is found that the filling process is stable and there is no obvious wall attachment phenomenon.
In the simulation analysis of the solidification process of the new process, through the solid rate distribution diagram, it can be seen that the lost foam casting solidifies gradually from the bottom to the center of the riser, and the feeding channel of the riser is unblocked; Combined with the solid phase rate distribution diagram, solidification time distribution diagram and shrinkage porosity and shrinkage cavity distribution diagram, it can be seen that after solidification, there is no shrinkage porosity and shrinkage cavity in the lost foam casting, but only a small amount of shrinkage porosity and shrinkage cavity in the riser.
Combined with the simulation analysis of the mold filling and solidification process of the new process, it can be seen that the mold filling of the improved process is stable, and there is no shrinkage cavity in the lost foam casting, which meets the application requirements. When the improved process was used in production, it was found that the quality of lost foam casting met the application requirements.