Technical ceramics 3D printing is the most advanced segment of AM and that also makes it the hardest to implement. One challenge is that there is no ceramics rapid prototyping: technical ceramics are end-use materials, in fact, they are often the best end-use materials; they come into play only when all else fails. That’s why they are so fascinating. Technical ceramics 3D printing is the fringe of 3D printing: in terms of material availability, system capabilities and product quality, Austrian company Lithoz can be considered the technological leader in this segment. Certainly they are the most experienced among ceramics AM hardware providers. When Lithoz’s Co-founder and CEO invited me to visit their HQ in Vienna, to learn more about the company’s business model and vision, I seized the opportunity to see exactly how Lithoz is ready to scale up.
Lithoz is one of my favorite companies in the AM industry since – at Euromold 2013 – I first saw the amazing ceramic parts they are able to deliver using their proprietary LCM (lithography-based ceramic manufacturing) technology. They were the first company to deliver a commercially viable DLP stereolithography based system to process advanced ceramics. Their capabilities have increased over the years, especially in terms of materials selection but also in terms of productivity.
The main challenge for Lithoz is the same that all ceramics AM operators face: gaining industrial awareness and driving adoption. These challenges are not so much technological: Lithoz’s team of engineers is at work on so many projects that it’s hard to keep track of them all. Accurately conveying these capabilities to the market of potential adopters can be more tricky than inventing them.
Ceramics 3D printing companies need to target very specific and yet difficult to reach adopters: generalist 3D printing services don’t usually offer ceramic 3D printing due to the many challenges associated with processing and post-processing these advanced materials. So the key adopters for ceramic 3D printing are usually either specialized ceramic 3D printing services – such as Steinbach, in Lithoz’s case, but also others – or ceramic industry part suppliers that decide to provide 3D printed parts to their clients.
Welcome to Lithoz
One thing I was always curious about Lithoz is the origin of its name: it comes from the Greek term “litho”, which is a combining form meaning “stone,” used in the formation of compound words – such as lithography. At Lithoz I was welcomed by Dr. Homa and by Isabel Potestio, who is now in charge of business development at the company. Dr. Homa and the Lithoz’s founders first started working on ceramics 3D printing at TU Wien in 2006. “It only took us a year to get the very first ceramic 3D printed parts,” Dr. Homa recalls. “However it took us almost five years to achieve a proof of concept for a part that would feature the same properties of a traditionally manufactured ceramic part. So we founded Lithoz, as a spinoff of TU Wien, in 2011.” This significant difference between a “casually” 3D printed ceramics part and a fully dense 3D printed ceramics part with full mechanical properties, is the basis for all of Lithoz’s activities and also the reason for Lithoz’s reluctance to convey the full potential of its ceramics AM technology.
“As engineers, we often choose not to illude our clients with promises that may not be met. Sometimes that is a limit – Dr. Homa admits – since the AM industry often moves in unpredictable ways and the failure to achieve one result can lead to success in another, unexpected, application. I do believe we have lost out on some sales because of our rigor in characterizing what a ceramic 3D printer can and cannot do.”
Nevertheless, the company has been growing quite healthily and its goal is to build a solid business for the long term rather than go after quick sales. In terms of human resources and office space, growth has been in the high double digits since the company’s founding. Lithoz moved into a fascinating and somewhat “cyberpunk” early XX century building, in the city of Vienna, and has gradually expanded to take over an entire floor. Here the company has its offices as well as the assembly plant. In the latest expansion, it is also building a new showroom for clients to come and learn about the systems’ capabilities. The number of employees is also growing by 2-3 persons each month with over 70 people now employed, between the Austrian HQ and the Lithoz America subsidiary opened in 2017. A key push toward expansion was provided by AM Ventures who entered as a minor shareholder in 2014, while machines sales, that have now topped 70 systems worldwide, also provided key funding. However, Dr. Homa agrees that the time has now come for ceramics AM to scale up.
Why ceramic 3D printing makes sense
The benefits of 3D printing ceramics are evident: improved geometries and better processability of extremely tough materials. So are the benefits of using ceramics in general, which show by far the highest mechanical properties by material weight. Bringing these two elements together is not as easy as it sounds and most ceramic 3D printing companies continue to operate within niche markets mainly within the medical, dental, aerospace, electronics, energy and automotive segments.
Lithoz has materials to operate in all these segments and many more currently in development. The company has developed 3D printable slurries – mixtures of ceramic powder and a photopolymerizable liquid to enable the stereolithographic process – based on alumina and zirconias, as well as silica-based materials and more advanced silicon nitrides. For the medical segment, the range includes several grades of hydroxyapatite (HA) and tricalcium phosphate (TCP).
On top of these, Lithoz is also constantly working on the development of new materials, some of which are truly impressive. Research is currently ongoing on toughened aluminas and zirconias, as well as on 3D printing of various materials with a very high potential to broaden the range of possible applications, including porcelain, cordierite, glass-ceramics, bioglass, cordierite, piezoceramics and even moon dust (regolith). One material, transparent ceramic, is present in the image above (bottom right corner). Dr. Homa shined a light through it to show how the printed part shows no imperfection whatsoever, meaning it printed perfectly and is fully dense.
Flying low, Lithoz is ready to scale up
Now Lithoz is ready to scale up its business and it’s easy to imagine aerospace and automotive parts mass-produced using Lithoz’s ceramic 3D printing technology. In fact, while Dr. Homa often repeated how the company’s policy is to avoid making statements that are too optimistic, Lithoz recently introduced a new system tailored for serial production, the CeraFab S65, which features up to four integrated build units. This means that the company is eyeing a significant scaling-up in productivity however the first segments to truly implement high throughput production may not use it for industrial end-use products.
One segment that Dr. Homa and Lithoz have identified as one of the most significant short term opportunities is the production of ceramic cores for investment casting of turbine blades. “While some turbine blades can be directly 3D printed in metal, other operate in environments where they get so hot that they reach a temperature above the melting temperature of any metal,” Dr. Homa explained. “In these cases, single-crystal superalloys are used and these cannot be 3D printed. In order to leverage the geometric benefits of additive manufacturing, our customers can use our technology to produce geometrically complex ceramic cores, even some that are as tall as 30 cm or with multiple wall solutionsThus a highly sophisticated internal structure can be introduced to further increase cooling. These are done in silica-based material which can be dissolved and cast out in a very strong basic environment.”
Dr. Homa believes that this is a segment where additive manufacturing is now on the edge of making a real breakthrough in terms of adoption. “The benefits of using a 3D printed ceramic core to produce complex turbine blades as single parts rather than through multiple die-cast parts are evident, both in terms of the part’s strength and for streamlining the manufacturing process,” he says. “We think that the largest turbine manufacturers are now ready to consider introducing 3D printed cores in their processes and that this could be one of the first mass-production adoption cases for ceramics additive manufacturing. This does require a change in mentality, where to implement scalability they’ll need to accept using several smaller size machines rather than one very large machine.”
The next interesting segments are dental and medical applications. Lithoz has over 8 materials, within its LithaBone. LithaCon and LithaNit and LithaLox ranges, which have been certified for biocompatibility (either cytotoxicity or genotoxicity and sensibilization). These have been used in CeraFab 3D printers installed in North America, Europe and South America, for production of CE/FDA certified medical devices and in surgery for bioresorbable and permanent patient-specific implants.
“Different materials enable us to cater to very different specific needs. LithaBone TCP, for example, is completely resorbable. HA, on the other hand, is less resorbable but stronger,” says Dr. Homa. “Then we also have LithaCon Zirconia used for dental applications or LithaNit, silicon nitride, which has great antibacterial properties. We can also offer homogenous mixtures of ceramic materials to meet specific material properties required.”
Challenges and opportunities ahead
The biggest challenge to address today remains the creation of market demand. Many companies that produce ceramic components, especially advanced ceramic components, could be benefiting significantly from subassemblies and DfAM (Design for Additive Manufacturing) ceramic parts but they still need to imagine, envision, design and develop the parts that will make ceramic AM processes and materials truly valuable. This is as an opportunity for aggressive companies to step up and make a compelling business case and provide the necessary support and expertise that are available with polymer and metal-based additive manufacturing-based solutions.
In fact, the emergence of bound metal printing technologies may play right into the capabilities of Lithoz and other companies that have already optimized a high-resolution slurry based process. The shared consensus now is that a two-step process where 3D printing and sintering take place separately can be better suited for high throughput production. Bound metal powder extrusion or metal binder jetting combine a polymer binder with metallic powders, and the same is occurring in slurry based processes. Lithoz can leverage its engineers’ experience to develop slurry based metal 3D printing processes and applications. In fact, the company showed the first metal-based applications at Formnext in 2018 and that was probably just the very beginning.