Assessing the Feasibility of Camphor-Assisted Vat Photopolymerization of Alumina for Ultra-Rapid Debinding and Sintering

Vat Photopolymerization (VPP) enables the fabrication of complex ceramic components with a high resolution between 10 and 200 µm. However, the process is limited by slow thermal debinding and sintering. In this study, a new photosensitive alumina (Al2O3) resin was developed using camphor as a diluent to reduce viscosity, enabling successful printing at a high ceramic loading of 56 vol%. A comprehensive feedstock optimization strategy was implemented with a particular focus on rheological behaviour. Two geometries, a thin bowl (0.42 mm thick) and a cylinder (1.2 mm thick), were fabricated to investigate the influence of thickness on ultra-fast high-temperature sintering (UHS). Thin samples were debinded and sintered using a step-wise UHS profile, whereas thicker cylindrical parts required a separate debinding stage. Under optimized thermal conditions, both geometries achieved relative densities up to 97% without observable defects, demonstrating UHS as a rapid and energy-efficient alternative to conventional ceramic sintering.