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S. Gruber, R. Felzmann, G. Mitteramskogler, R. Liska, J. Stampfl:
"Generation of ceramic parts via lithography-based AMT";
Talk: Materials Science and Engineering 2012, Darmstadt; 09-25-2012 - 09-27-2012; in: "MSE Programme", (2012), 37.

In this work, materials and systems for the fabrication of ceramic parts by lithography-based additive manufacturing are presented. Key component of the utilized systems are DLP-based light engines (Digital Light Processing) which use powerful LEDs and a 1080p DMD-chip (Digital Micromirror Device) that generates images (dynamic mask) at 1920x1080 pixels with a pixel size of 40 microns. The overall build size of the system is 76.8x43.2x100mm. This 3D printer is capable of processing a variety of ceramic materials (beta-TCP, alumina, zirconia and bioglass) to produce high-precision ceramic parts.
By dispersing the ceramic particles in a photosensitive resin (slurry), these materials are made processible by lithography based additive manufacturing. During the printing process, a thin layer of the slurry is exposed locally as a result the slurry solidifies (polymerizes). Thus, the so called green body is printed layer by layer. The standard layer thickness ranges from 25 to 50 microns. In the subsequent drying, debinding and sintering steps, the green body - containing solvents, a crosslinked polymer network and ceramic powder - is transformed to a fully dense ceramic part (> 99 % of theoretical density).
The combination of modern LED technology, coating mechanism suitable for high viscously slurries (10 - 20Pa.s) and exposure strategies enables the production of complex geometries of virtually any type. Reproducibility and quality of the parts was considerably improved and visualized through the implementation of several sensors. High building speeds of 10 vertical mm/h show the potential of the system for industrial applications. So far, slurries with a solid loading up to 50vol-% ceramics could be processed successfully. The bioglass and alumina specimen fabricated in this work showed a biaxial flexural strength of 40MPa and 516MPa, respectively and a Weibull modulus up to 13. The sintered beat-TCP specimen showed a biaxial bending strength of 30MPa.

http://publik.tuwien.ac.at/files/PubDat_210425.pdf