Hybrid additive manufacturing for the fabrication of freeform transparent silica glass components

Additive manufacturing of ceramic and glass materials has been developed extensively over the past years, revealing strengths and limitations of the various technologies. In this work, a hybrid extrusion-photopolymerization process is developed to exploit the benefits of both approaches. Their combination allows for more complex geometries with less rheological constraints and no influence of scattering and/or absorption. With this method, transparent silica glass 3D honeycomb-like structures are fabricated starting from a suspension that combines silica particles and a silicon alkoxide. The rheological behavior and reactivity of the ink are tailored with an appropriate blend of acrylates as well as with the alkoxide addition. The latter also contributes to the final ceramic yield, allowing for faster thermal treatments despite a low particle loading. The final components closely match the shape provided by the CAD model; their physical properties confirm the formation of a fully dense silica glass after the heat treatment.