Investment Casting With Ice Pattern

In this paper investment casting with ice pattern, freeze casting process (FCP), was investigated. FCP is a novel and environmentally conscious precision casting process with ice pattern instead of wax pattern in which shell mold is made under freeze temperature, but ice pattern melts at room temperature.The integrated process and key technology were studied through experiments in which several silicone molds, ice patterns and castings were made. And the dimensional change pattern from prototype, ice pattern to mould was analyzed at different temperatures, which is important to casting precision. Using heat transfer theory, the characteristic of ice temperature and solidification was discussed. Also, by drawing a comparison test between different binders and catalysts respectively, the optimal binders, catalysts and ceramic powder for making shell were chosen. The test results of three-point bending and thermal expansion for shell made by FCP and common process respectively were compared. Microstructure of shell surfaces with different processes was observed using scanning electron microscopy (SEM). The interface reaction between shell and ice pattern was analyzed, and the heat quantity transfer was calculated. The rough surface of shell was settled by processing methods. The results indicated that shell made under freeze temperature supported casting conditions.With previous optimized materials and process parameters, a stainless steel parts was made. The test results showed that the process of investment casting with ice pattern was practical for producing high quality castings.