Mitigation of warpage in stereolithography 3D printed ceramics via addition of sterically bulky acrylate monomer

In vat photopolymerization of ceramics, warpage and delamination often cause printing failure, particularly in parts with large area‐to‐thickness (A/T) ratios. Yet, a direct approach to reduce warpage by altering resin formulation remains underexplored. Herein, isobornyl acrylate (IBOA), a reactive monofunctional monomer with a bulky bicyclic group, is introduced to control cure shrinkage‐induced warpage in stereolithographic 3D‐printed ceramic parts. The addition of IBOA to commonly used acrylate‐based resin was found to significantly reduce cure shrinkage (up to 22% with 35 wt% IBOA) even though the degree of polymerization was increased. The steric hindrance effect from the bulky bicyclic group was identified to be crucial to suppress the cure shrinkage. With 35 wt% IBOA, an exemplary alumina slurry exhibits much lower viscosity and enables nearly warpage‐free printing of long ceramic bars with a high A/T ratio (up to 350 mm). Post‐sintering analysis revealed that these alumina ceramic bars achieved a high relative density of ∼95.0% and a flexural strength of ∼283.2 MPa, comparable to the other reported vat‐photopolymerized alumina ceramics. The optimized resin formulation paves a way for producing warpage‐free and complex ceramic parts via stereolithography, addressing the key printing limitations in conventional slurries.