Theoretical modeling based on stress wave propagation and experimental verification of residual stress in stereolithography printed ZrO2 ceramic suspensions

Zirconia ceramics are widely used in medical and dental industry due to their excellent biocompatibility and aesthetics. In this respect, stereolithography apparatus (SLA) is popular method for 3D printing of ceramic suspensions. However, deformation and cracking of SLA-printed ceramics caused by residual stress seriously limit their application in clinical dentistry. In this investigation, 75 wt. % ZrO2 suspensions were successfully prepared, and ZrO2 ceramic composites were produced via SLA 3D printing. Special attention was paid to the establishment of theoretical model of residual stress in SLA. According to results, the development of residual stress in SLA-printed ceramics depended on various parameters such as laser power, scanning speed, and radius of curvature, as well as linear shrinkage, stress wave, and pure bending stress. The variations of surface residual stress at different laser beam powers, scan speeds, and radii of curvature were found to be consistent with that predicted theoretically. The errors between the theoretical and experimental value were 2.8%, 1.4%, 4.3%, 5.3%, and 4.2%, respectively, when the laser beam powers increased in turn. The errors between the theoretical and the experimental value were 2.5%, 3.9%, 2.8%,2.4%, and 3.8%, respectively, when the scan speeds increased in turn. Thus, theoretical model established was proved high accuracy and conformity to 3D printing standards.