3D Printing: Making Technical Ceramics More Accessible
Today's additive manufacturing solutions cover the complete ceramics 3D printing value chain.
The ceramic industry is currently experiencing newfound freedom and creativity due to the rapid development of 3D printing solutions. Today’s advancements cover the complete ceramics 3D printing value chain, including on-demand production services, 3D printers, specific services designed to boost efficiency and a broad range of ceramic pastes.
The second industrial revolution heralded the mechanization and automation of the mass production of parts. The entire production system was organized for low-cost production. China became the workshop of the world, making it much more difficult to manufacture products that are not made in mass quantities. This approach runs contrary to the natural path of innovation. By definition, innovation consists in proposing something that does not already exist. However, without the capacity to invest in costly production machine tools to test an idea, how can you demonstrate its worth?
Against this backdrop, 3D printing was developed via the Makers movement in California. The goal was to get back to fabricating objects ourselves. Today, this technology resembles a new industrial revolution. In 2013, President Obama said that 3D printing “has the potential to revolutionize the way we make almost everything.”
Bringing the Revolution to Ceramics
Technical ceramics is no stranger to this revolution. The demand for the fabrication of complex parts—for both new designs and applications—depends on short lead times and little to no investment in tools. 3D printing forms a close fit with other conventional manufacturing technologies, and makes ceramics more accessible by cutting development times and simplifying the production process.
A 3D printer dedicated to ceramics has been developed that uses laser technology.* Laser stereolithography (SLA) has emerged as the best solution for the fabrication of dense ceramics with very good resolution. The parts made using the 3D printer have the same characteristics as ceramic parts produced using traditional technologies such as dry pressing or injection.
This technology specifies the use of a photosensitive monomer, which is loaded with ceramic particles. This ceramic is spread onto a working plane in layer thicknesses of 25-100 microns. An ultraviolet (UV) laser polymerizes the section of the object being produced. Once this portion of the object is solidified, another layer of paste is spread on top of the previous one; the laser polymerizes the new layer, and then “glues” the layers to one another. The process is repeated until the final part is obtained. After extraction of the solidified part from the uncured ceramic and cleaning off the unpolymerized residues, the part is debinded and sintered to give the ceramic its final properties and the definitive dimensions of the manufactured object.
Using the laser makes it possible to provide a steady and constant output for perfect polymerization, guaranteeing homogeneous raw material. It gives a better homogeneity of ceramic and a higher density of the sintered material for better resistance of the finished part, as well as a more precise control of dimensional changes of the part during firing.
The 3D printer features numerous developments designed to make it easier to load the ceramic paste and to feed the paste into the fabrication zone. Optimizing these functions significantly reduces consumption of the ceramic paste and improves production quality.
The ceramic pastes used in the printing process are the key to high-quality end products. A relatively broad range of ceramic pastes is available to meet manufacturers’ needs, including alumina, zirconia, hydroxyapatite, etc. These pastes, which are made of 80% ceramic powder and 20% resin, are available in cartridge form for use in the 3D printer. (They are also compatible with other 3D printers, due to significant work carried out on the size of the particles of the ceramic powder and the flow characteristics of the paste in the fabrication process.)
Looking to the Future
Today’s R&D is focused on the development of ceramic formulations and on meeting new needs (e.g., new colors, formulations in different phases, new materials, etc.). “Loaded resins” consisting of 20% resin and 80% ceramic powder provide the opportunity to pave the way toward new applications, especially when customers are looking for “ceramic characteristics (resistance to heat, surface condition),” but with demands for dissimilar mechanical properties. Since these resins loaded with ceramics cannot be sintered, they don’t compete with technical ceramics.
3D printing dedicated to ceramics has progressed from being a prototype manufacturing technology in 2000 to becoming a reliable production technology today. Markets such as luxury goods already consider it to be a production technique in its own right that meets the demands for personalized product ranges. Additive manufacturing for the aerospace industry, with really dense ceramic, is also becoming a possibility. The revolution is here!