Vat photopolymerisation 3D printing of ceramic core with regulation on rheological and curing behaviour based on spherical powders

Due to its geometric versatility, vat photopolymerisation (VPP) 3D printing technology is a sophisticated method for making ceramic cores from high-quality ceramic slurries. This study systematically examines how spherical silica powder concentration in VPP-3D printed ceramic slurries (0-8 wt.%) affects ceramic core rheology, curing, and effectiveness. The results show that spherical powders lower slurry viscosity and improve flowability and particle distribution. However, high quantities (>6 wt.%) increase porosity and decrease mechanical properties due to insufficient sintering. Spherical particles’ geometric symmetry decreases UV light scattering and improves photopolymerisation transmission, allowing deeper curing as their number increases. To explain the regulatory mechanism governing spherical particles during photopolymerisation, a shape factor k is proposed to account for refractive indices. A complete performance analysis shows that 6 wt.% spherical powder maintains surface quality, shrinkage below 3%, and mechanical strength of 12 MPa at ambient temperature and 18 MPa at high temperature. This empirical data provides a theoretical foundation and practical guidance for improving ceramic core VPP-3D printing. It also shows that the right amount of spherical powder balances printing accuracy, sintering density, and high-temperature efficacy, which benefits precision casting. It functions as a substantial reference within this specific domain.