In the investment casting process, wax patterns are formed by injecting hot wax into metal dies. The wax shrinks in the die as it cools down. Estimating the wax shrinkage is very important for dimensioning the pattern tooling. In order to predict the wax pattern dimensions after shrinkage in the die using numerical simulation of wax solidification and deformation, the heat transfer coefficient between the wax and the die must be determined. Temperature measurements were made during wax injection and subsequent cooling in the die. It was found that heat transfer through the thermocouple wires significantly affected the accuracy of the temperature data. Accordingly, the wax-die heat transfer coefficient was determined by numerical simulations of the heat transfer in the thermocouple, wax, and die assembly. The best fit to the measured experimental data was provided by a time-dependent heat transfer coefficient.
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