[Back]

J.-A. Schönherr, S. Baumgartner, M. Hartmann, J. Stampfl:
"High-precision Lithography-based Ceramic Manufacturing (LCM)";
Talk: Materials Science and Engineering - MSE 2018, Darmstadt; 09-26-2018 - 09-28-2018.

Starting in the early 90s Additive Manufacturing (AM) developed as a rapid manufacturing tool and today is comparable to common manufacturing methods. AM is connected to digital tools such as 3D-scanning or computer tomographic imaging and it enables the production of parts with highly complex geometries, which has not been possible with conventional methods. Therefore, AMT can be utilized as an ideal production method for direct fabrication of refractory moulds and cores or biomedical applications like implants even in small or individual batches. Dental replacements such as crowns or implants need high precision and high mechanical properties which can be obtained by Lithography-based Ceramic Manufacturing (LCM). This method uses a light source with a defined wavelength, for example a laser, or powerful Light Emitting Diode (LED) to cure and structure a photosensitive resin which can be filled with ceramic powder. It is possible to structure different ceramics like alumina, zirconia or tricalcium phosphate with a solid loading up to ~50 vol%. One goal of this study was to find out the best way to digitize LCM processed glass ceramic parts, especially dental molar crowns. Different scanning methods have been tested like an infrared laser scanner, a tactile scanner or micro-CT. With the ideal scanning system, the precision could be evaluated by laying the scan on top of the digital file by using the software GOM inspect. We demonstrate an improvement of the whole process chain, beginning by support structures that obtain optimal building conditions and at the same time, reduce the sinter warpage. Moreover, it was possible to reduce the influence of z-overexposure and to find the optimal shrinkage parameters. As a result, a resolution of 25 µm in all spatial directions was achieved.