Conference paper given at the 32nd International Conference on Digital Printing Technologies (NIP).
Materials and processes for additive layer manufacture have advanced considerably in the last few years and have moved the application of the technology away from prototyping to fabrication and manufacture. One area that still has little effective presence is that of 3D printed ceramics. Ceramic materials have proved difficult to integrate with 3D printing technologies and there is still a considerable way to go before the characteristics of most of these materials can be considered adequate.
The problems experienced are high firing contractions, low density and strength, and potential incompatibility with glazes. For general tableware and giftware ceramics two main methods of 3D printing are used; paste extrusion through a syringe and fine nozzle, and a powder binder system that inkjets binder onto a powder bed containing a mix of ceramic powder and an organic binder.
The paste extrusion system has the advantage that conventional ceramic pastes and bodies can be used but the layer thickness is coarse and there can be problems with maintaining an even extrusion of a thin bead. The main issue with this method however is the restriction on geometric freedom that cannot compete with other 3D printing methods.
The powder/binder process gives the ability to form complex shapes, but has an inherent high porosity due to the burn out of organic binders and the restriction on particle size required for the process to function correctly. The manufacture of high performance monolithic ceramics such as alumina and zirconia is achieved by using photo cure resins with a high loading of ceramic material, this requires a thermal de-bonding process that results in a very high firing shrinkage that can effect the dimensional stability in the firing/sintering.
The reasons for wanting to use ceramic materials are to utilise their unique properties but the limitations of the available processes make these properties difficult to realise by current additive manufacturing methods.
This paper reviews and compares contemporary ceramic additive manufacturing processes and explains why the above issues exist and explores potential solutions. Researchers at the Centre for Fine Print Research at the University of the West of England in Bristol have a history of over eight years of research into 3D printed ceramics and have developed and patented materials and processes in this area. They have collaborated with leading ceramic manufacturers and material suppliers in the UK to improve and refine the process. Ongoing research into this area at the University of the West of England is exploring potential solutions to these issues including; hybrid extrusion/machining for paste extrusion ceramics , colloidal infiltration of preformed powder/binder, and 3D printed and novel methods of pre-processing ceramic powders used in powder/binding 3D printing to increase the density and fired performance of the ceramic material.
Huson, D., & Vaughan, K. (2016, September). 3D printed ceramics: Current challenges and future potential. Paper presented at Printing for Fabrication 2016 (NIP32)