Multi-dimensional optimization of slurry and synergistic suppression of interlayer cracking by layer thickness in DLP 3D printing silica-based ceramic cores

A better comprehensive performance of the slurry is the primary condition for preparing ceramic cores by digital light processing (DLP). This study developed a multi-dimensional optimization evaluation method for preparing the ceramic slurry. The proposed time-scale viscosity (TSV) more accurately reflected the slurry's dynamic characteristics in its actual printing state. The quantification of the loss factor (Formula presented)  = G″/G′ and the apparent contact angle revealed the microstructural properties of the slurry. A relationship was established between the surface quality of green-body ceramics and sintered ceramics. In addition, the interlayer bonding of green bodies with different layer thicknesses (LTs) and the stress-strain mechanism of sintered samples were also established. The results showed that the shear thinning characteristics of the slurry were more stable under the time scale in the linear viscoelastic (LVE) region when (Formula presented)  ≥ 1. The maximum Ra and Sa of the cured monolayer surface of the JJ-86 dispersion system were below 2.0 μm and 3.0 μm, respectively, and the optimized slurry of the JJ-86 dispersion system had a minimum viscosity of less than 1.1 Pa s (100 s⁻¹) at the time scale. The interlayer bonding strength of the ceramic samples with 30 μm and 60 μm layer thicknesses were superior, with 10.377 MPa and 10.862 MPa, respectively. The synergistic control resulted in high-quality ceramic core samples with Ra and Sa of 2.448 μm and 3.291 μm, respectively, as well as crack-free sintered ceramics with larger Z-axis dimensions.