Supercritical Fluid Treatment as Fast Preconditioning Process

The aim of this doctoral research project is to develop supercritical carbon dioxide extraction process as a fast preconditioning method for ceramic 3D prints. Vat photopolymerization printing can be used to produce ceramic parts with complex geometries and it provides an alternative solution to e.g., CAD/CAM milling of ceramic dental restorations, in which even 95% of the used material can go to waste. However, the printing process requires use of a substantial content of organic binder polymers to maintain the printed 3D shape of the part. This organic content must be burned away to obtain the final ceramic part. The post-processing by furnace treatments can last 10 days and remain the major bottleneck in the vat photopolymerization printing process.

The post-processing can be shortened by supercritical carbon dioxide extraction that removes a part of the organic content of the prints prior to thermal debinding, thus creating porosity as an easier route for the degradation gases to exit through. This enables shorter heat treatments, making the process more economical and ecological.