DLP 3D-printing of sol-gel based silica-zirconia glasses

Abstract: Glass materials are widely used in a variety of industries due to their unique properties. Conventional methods for manufacturing glass components require high energy and they are incapable when it comes to process complex structures. Modern manufacturing techniques have been explored to produce complex 3D printed glass parts; however, these techniques still need improvement to achieve better optical quality in the final products. This study focuses on the development and optimization of the sol-gel-based photocurable feedstocks compatible with digital light processing (DLP) 3D printing technique, aiming to enhance printability and optical transparency. In this work, silica precursors together with a transition-metal alkoxide were combined in sol–gel formulations, where the choice of acrylates, high-boiling-point solvents, and chelating agents was carefully adjusted to achieve a balance between reactivity, viscosity, and chemical stability. Meanwhile, several key challenges were addressed, from controlling the sol-gel reaction kinetics, to ensuring solution stability and minimizing crack formation. In parallel, great effort was dedicated to adjusting processing parameters of the DLP printer such as exposure time and thickness of layer, as well as aging time and thermal treatment protocol. Despite initial issues with printing complex structures, the final samples with the optimized formulations were successfully printed in various complex geometries with high resolution which, after thermal treatment, resulted in amorphous silica–zirconia glass with improved optical appearance.