Recyclability of ceramic powder in CerAM vat photopolymerization

The sustainability of the manufacturing industry is becoming an increasingly hot topic, particularly the reintroduction of waste into the production chain. The use of AM of ceramics can reduce waste and enable complex, lightweight designs, however, practical routes to circularity remain underdeveloped. This investigation aims to explore the potential of coupling these additive fabrication techniques with raw materials from alternative sources of ceramics, such as printing wastes and error prints, developing a photocurable ceramic suspension for DLP technology. For resin preparation, a polymeric premix was first prepared by combining a mixture of different acrylate monomers as a photoreactive binder with a non-reactive plasticizing additive. Alumina was recovered from failed green bodies following matrix burning out, parts grinding and sieving of the obtained powder. Subsequent investigations of the powder by SEM imaging and EDX analysis were carried out to verify particle morphology and average dimensions and to identify any contaminants in the recycled material. The suspension viscosity and curing behaviour were measured. Finally, the mechanical characteristics of printed parts, their density, their shrinkage, as well as possible contaminants, were evaluated, in order to understand the impact of the recycling process on material performances and to determine its possible application fields. Tests results provided a practical recycling potential for alumina in DLP, offering viable solutions in facilitating closedloop CerAM manufacturing.