Predicting Pattern Tooling and Casting Dimensions for Investment Casting
In this project, tools are being developed to predict pattern tooling and casting dimensions for investment castings. Currently, the investment casting process involves the creation of a disposable wax pattern by injection into a metal mold. A ceramic shell mold is created around the wax pattern by the application of a series of ceramic coatings to the wax pattern. The ceramic shell mold is dewaxed and the alloy is cast into the dewaxed shell mold. The final linear dimension of the casting depends on the accumulated effects of the linear expansion or contraction in each step of the investment casting process, including the solidification and thermal contraction of the casting itself.
Prediction tools being developed in this project will take into account the thermal expansion, the mold restraint on the wax and alloy, and the resulting plastic, creep, and elastic deformation of wax, shell, and mold materials during solidification and subsequent cooling. The molds also will take into account the solidification characteristics of the wax and alloy, and consider solidification shrinkage.