3D printing of porcelain and finite element simulation of sintering affected by final stage pore gas pressure

Abstract Ceramic 3D printing involves various sintering phenomena such as shape distortions, crack formations, shrinkage anisotropy, and residual porosity that demands the development of a simulation tool. Moreover, liquid-phase sintering of materials such as porcelain exhibits an additional and challenging phenomenon at the end of the sintering process that reflects closed porosity growth and coalescence owing to the pressure created by the pore-trapped gases, which further implies swelling (or bloating) of the entire specimen accompanied by distortions. In this study, the swelling issue of 3D-printed porcelain samples was investigated through a sintering dilatometry parametric design to determine the optimal heating rate and holding temperature. A sintering modeling theory was employed to characterize the final stage pore gas pressure via an inverted sintering model formulation. Finally, a finite element sintering simulation was applied based on the analytical model data to predict the sintering shrinkage of a complex geometry.