A new slurry-based shaping process for fabricating ceramic green part by selective laser scanning the gelled layer

This paper proposes a new slurry-based shaping process for fabricating ceramic green parts. Slurry was composed of SiO2 powders (without polymer coating) as a structural element, silica sol and polyvinyl alcohol (PVA) as binders. The new process derived gelling effect from vaporization to generate a uniform gelled layer. By selective laser scanning, an alkali-insoluble 2D pattern was formed on the gelled layer. A green part was built by sequentially layer casting, drying, selective scanning and self-supporting removing. Because gelling occurs uniformly in the whole fresh layer, distortion is minimized. Therefore, this process not only can cast thinner layers to improve the staircase effect but also achieve a better surface by preventing surface pitting induced by laser ablation. No additional design for supports is required since overhangs and undercuts are supported by an inherent gelled support. Compared to other slurry-based processes, the process possesses time-efficiency in slurry preparation and support removal.