Response mechanisms for the photopolymerization profiles, microstructures, and properties in ceramics prepared by stereolithography

Insight into the response mechanisms among the photopolymerization process, profile curves, microstructure, and physicomechanical properties is essential for microstructural and performance control during ceramic stereolithographic manufacturing. This work establishes and validates the photopolymerization profile equation and investigates the response mechanisms of photopolymerization profiles on microstructures and lamellar defects and the response mechanisms of cured powder concentration gradient on dimensional shrinkage, porosity, and physicomechanical properties. The results illustrate that the profile control equations perfectly predict the photopolymerization experiment profile and the lamellar profile shape to control the volume of lamellar defects, and the surface microstructures are mainly affected by the z-direction lamellar profile. The optimal surface roughness values of the green bodies before and after sintering are 3.95 μm and 3.32 μm, respectively. Besides, the attenuation of the Gaussian-distributed laser intensity in the slurry results in a gradient change in double-bond conversion to create a gradient in the cured powder concentration. The z-direction shrinkage strongly correlated with the cured powder concentration is much greater than the x- and y-direction shrinkages. The variation range of the anisotropic shrinkage is from 1.54 % to 3.77 %. Furthermore, the cured powder concentration on the top area of the cured layer near the laser irradiation is greater than that on the bottom area away from the irradiation, influencing the physicomechanical properties. Finally, the best process parameters for multiobjective optimization are achieved by combining response surface experiments and principal components analysis. The response mechanisms of the lamellar profile and cured powder concentration are expected to provide new ideas for controlling the performance of vat photopolymerization. •Photocuring profile equation is established to supervise the actual profile curves.•The shape and volume of lamellar defects are quantitatively analyzed and predicted.•Cured powder concentration gradient is induced by attenuated curing conversion.•Anisotropic physicomechanical properties are affected by cured powder concentrations.