Micro-flow investigation on laying process in Al2O3 stereolithography forming

When printing Al2O3 parts by stereolithography technology, the laying process is an extremely important part. In the current work, the referred flow analysis was numerically investigated. The rheological behavior was measured to determine the rheological type of the slurry. According to the fitting analysis, a Sisko model was available to describe the non-Newtonian behavior. Then, the modified multiple relaxation time lattice Boltzmann method was proposed and validated to effectively improve the stability of the simulation. Based on the proposed method, the situations without and with printed solids in the previous layer were investigated by a series of simulations. The laying velocity and layer thickness were considered as two important factors on the laying process. When the situation without printed solids in the previous layer is analyzed, the streamlines and flow velocities curves were almost horizontal. With different laying velocities, the flow velocities show obvious differences at the same thickness. With different layer thicknesses, the difference is mainly embodied in the vertical velocity component. When the printed solid is considered, the solid seriously affected the smooth flow. The vortices appeared near the printed solid, which also caused the disturbance in both horizontal and vertical velocity components. The mentioned interfering factors indicated different actions on the flow. The research will contribute to understanding the flow of the laying process. It can help to select suitable laying velocity and layer thickness to avoid severe flow velocity fluctuation and redundant vertical velocity components.