Shaping of ceramics by hybrid binder jetting
Résumé
Additive manufacturing by binder jetting is becoming increasingly popular to process ceramics. This technology is not only highly productive but also all-material compatible and is one of the few truly "free form" additive processes. Unfortunately, it suffers from a series of limitations that are not yet fully resolved. These include the low density of the sintered parts, which makes them unsuitable for structural use, and the rather rough surface of the parts produced. A significant research effort is underway to overcome these limitations. The literature is full of attempts to improve this technology either with extensive work on the powders or with significant hardware modifications.
This presentation reports preliminary results obtained on a new type of hybrid binder jetting equipment used to manufacture of alumina parts. The used system is dual: additive and subtractive. It includes an in-situ mounted laser whose purpose is to refine the contour of each printed layer, thereby improving the resolution and smoothness of the part.
The presented results describe the optimal operating conditions to ensure a maximum densification after sintering. The benefit of a post-infiltration of parts with a loaded suspension is highlighted. Alumina parts with densities up to 88% of the theoretical density have been produced. The benefit of the laser is also shown up with roughness values improved by a factor 3 over conventional printing.