Ultra sonic spray coating of silica nanocomposites for smoothening 3D-printed fused silica glass and metal casted injection molding tools

3D printing has gained a lot of interest, enabling the fabrication of complex geometries and the use of a wide range of materials, including glass. However, a major limitation of 3D printing is the surface quality, which often makes it unsuitable for producing optically transparent components. Although a wide range of post-processing methods was explored to enhance surface quality, these techniques have been restricted to polymeric materials and flat or slightly curved surfaces. Recently high-resolution indirect glass 3D printing was introduced by printing glass nanocomposites, which can be subsequently debinded and sintered to transparent fused silica glass. In this work we demonstrate for the first time that optically smooth transparent glass geometries can be achieved by spray coating adapted silica nanocomposites onto the printed parts prior to the thermal heat treatment. The process enables manufacturing of complex, optically transparent fused silica glass geometries with a surface roughness below 16 nm (Sq), using commercially available printers. Furthermore, we demonstrate that these fused silica glass components, once produced and refined, can be effectively adapted for metal casting and the manufacturing of multi-sided injection molding tools. This, significantly enhances prototyping of optical glass components as well as for tool-based manufacturing processes.