Updated: Aug 18, 2019
Every undergraduate majoring in ceramics learns quickly that the Achilles’ heel of ceramics is its brittleness. Unlike metals that are ductile and workable, ceramics is difficult to shape by machining. I did my Ph.D. in “superplasticity of ceramics”, which aimed to create ceramics that are “super-plastic” compared to normal ceramics. But even superplastic ceramics can only be shaped at very high temperature and the shaped object end with plenty of porosity, which reduces its strength. Without efficient way of making complex shapes and structures, technical ceramics is severely limited in its use.
Precisely because ceramics is so difficult to shape, the fast-growing 3D printing technology has potential to make a difference. 3D printing, for the first time, allows ceramic powders to be deposited precisely where they need to be, with the aid of a photopolymer or a binder. The photopolymer or binder is burned out in subsequent sintering, so some shrinkage is inevitable.
As with all 3D printing technologies, 3D printing of ceramics is not a panacea suited for every fabrication of technical ceramic objects. We think the fabrication technique is particularly suited for:
Objects that do not need fully dense ceramics, and can in fact benefit from porosity. For example, ceramic inserts for investment casting do not need to be fully dense as they will be removed later. The implant or bio applications also can benefit from porosity to allow cells to grow into the structure to form stronger bond. Not needing full density means smaller shrinkage in the final sintered object and a higher design fidelity.
Objects that are highly customized and individualized will benefit from 3D printing. For example, dental applications where every tooth is different has been a particular popular application for all 3D printing technologies from resin to metal. In the ceramic field, current method of making dental veneer requires painstaking shaping and polishing, and as a result, dental veneer is expensive at $500-2000 per tooth. 3D printing could dramatically reduce that cost.
Objects that are of high value. While 3D printing of ceramics can be used by everyday people to make highly creative art and craft, it is important to focus on high value products for start-ups if the business model is to sell the end products rather than 3D printing machine. In that perspective, industrial ceramics such as investment casting cores and ceramic valves are good applications.
Making high precision, high value technical ceramic objects in 3D printing is a multidisciplinary effort:
Precision mechanical control of the machine: the finer you can make the steps in printing, the more refined feature you can get
Software that takes 3D objects and can automatically slice and dice and compensate for shrinkage to come up with the essential parameters to control the printing step including printing sequence, light intensity, spot size etc.
Material formulation expertise in terms of resin/binder selection, material selection to minimize shrinkage and deformation in sintering
With the challenges of making good 3D printing products and identifying good applications, there are far fewer 3D printing companies in the ceramics field compared to 3D printing of resins, filaments or metal. A good overview of the current 3D printers of ceramics can be found at https://all3dp.com/1/3d-printing-ceramic-3d-printer/.
If you are working on developing world-class ceramics 3D printing technologies (equipment + software + material), we would love to hear from you!