Multi-material ceramic printing for functional components

Ceramic materials offer advantageous properties, such as high strength and resistance to temperature and chemicals. For high-performance applications, there is great potential to combine these properties within a single component in a way that suits its function, for example through locally tailored hardness, porosity, or thermal stress resistance. However, the industrial implementation of multi-material printing is limited by the lack of suitable material systems and manufacturing processes.

State of the Art

Vat photopolymerization (VPP) already enables high-resolution 3D printing with a high degree of geometric freedom. In this process, a liquid, light-sensitive polymer resin is exposed to light locally and layer by layer in a container (vat), causing it to cure selectively. Thermal post-processing is required for complete curing: excess material is evaporated using debinding agents, and the component is densified through the application of heat during sintering. Since different ceramics behave differently during post-processing, multi-material ceramic components are particularly challenging. Commercially available processes are therefore designed for single-material components.

Technology

The material system for multi-material additive manufacturing (MMAM) developed at the wbk Institute for Production Engineering addresses the need for ceramic hybrid components. Researchers at KIT combine VPP with specially developed ceramic slurries (a mixture of a binder containing a photoinitiator and ceramic microparticles). Localized exposure to light at a defined wavelength causes the material to cure layer by layer. For multi-material components, the system switches in a controlled manner between two slurry tanks during printing. This allows different ceramics with comparable shrinkage and sintering behavior to be combined, such as alumina and zirconia. An integrated cleaning station removes residual material before each switch. The printed component (up to 4x7 cm) undergoes thermal post-processing as usual.

Advantages

The developed binder system makes it possible, for the first time, to reliably 3D-print ceramic components with locally tailored properties. The system’s flexibility facilitates its adaptation to other ceramics and, in the future, to ceramic-metal composites as well. The close-to-net-shape manufacturing process, which produces parts with low surface roughness, reduces the need for mechanical post-processing and is particularly well-suited for prototypes and small-batch production.

Options for companies

Researchers at the wbk have developed extensive expertise in material development for multi-material additive manufacturing. KIT is seeking partners to further develop this technology.