Selective laser melting of ceramic-based materials for dental applications

Abstract

The employment ofthe Selective Laser Melting (SLM) technique in the processing o f ceramics has attracted attention recently. SLM is a powder-based AM process where powder spreading is one o f the fundamental. Therefore, a spray-drying process was chosen to improve powder properties to reach a proper powder for the SLM process. Also a dynamic powder characterisation methodology was used to investigate powder flow characteristic. A series o f SLM experiments were conducted using the spray-dried powder in three stages: single-track melting, single-layer melting and fabrication o f threedimensional (3D) blocks (multilayers). The objectives o f this set o f experiments were to establish the preliminary processing windows o f ceramics via SLM. Finally, multilayer or ceramic 3D blocks were experimented via SLM machine. However, the density o f the fabricated 3D parts was low and the parts were also fragile and unstable. These results showed that with current state o f technology, it is still a challenge to directly fabricate dense ceramic components using SLM. Following the insights obtained from these experiments, the critical challenges o f this project were identified and discussed, including ceramic powder layer deposition, laser-powder particles interaction, the dynamic melting and consolidation mechanism, process parameter optimisation and residual stress analysis ofthe ceramic materials processed with SLM.