Sintering behavior of ultra-thin 3D printed alumina lattice structures

Ceramic stereolithography or vat photopolymerization is a process allowing the fabrication of ceramic objects with highly complex shapes. Lattices structures are particularly used together with advanced optimization topology tools for the design of printable lightweight shapes with optimized mechanical resistance. If the mechanical resistance of these lattices structures is well controlled at the polymeric state, they can be severely deformed at high temperatures during the sintering stage. The deformation sensitivity of the lattices structures during the sintering should then be determined to include this aspect at the conception stage. The finite element (FEM) simulation of lattices sintering is an interesting solution to anticipate numerically the deformation sensitivity of the lattices and determine their minimum wall thickness. This requires to determine the sintering behavior of the printed green specimens and to take into account the sintering anisotropy, which involves weaker resistance between the layers. In this study the sintering behavior is first determined by multiple-axis dilatometry, modeled analytically and then simulated by the FEM method. Afterward, the sintering simulation of lattices with different wall thicknesses is conducted. This allows testing the simulation tool predictability for each lattices wall thickness and to compare their deformation sensitivity at high temperatures.