Crack prediction using nonlinear finite element analysis during pattern removal in investment casting process

A three-dimensional transient thermo-mechanical coupled nonlinear finite element model was developed to predict the possible crack formation of ceramic shell during rigid polymer pattern removal in the investment casting process. A smeared crack model was used to describe the response of the ceramic shell when crack initiates. A foam degradation model was implemented to account for the loss of mechanical properties of the foam during firing process. The effects of firing method, pattern type and complex geometry were investigated. The simulation results were validated with experimental findings. The developed model not only serves as a useful tool for designing foam patterns but also can be used for optimizing firing process parameters in investment casting process.