Opportunities and challenges of ceramic additive manufacturing for restoration of historic porcelain artifacts

Three different Additive Manufacturing (AM) methods for ceramics (CerAM VPP, CerAM FFF and CerAM PBF) and traditional slip casting in 3D-printed plaster moulds have been investigated concerning their suitability for making components of traditional porcelain with special focus on restoration of historically valuable porcelain artifacts from the 18th and 19th century. For that purpose, fragments of historical artifacts were reconstructed and transferred into CAD data. For each AM method specific semi-products must be prepared like light-curable suspensions, thermoplastic filaments, or granulates and suited process parameters for each AM methods were developed. Several challenges are to be solved which are especially related to the demands of restoration - first, the complex structure of the fracture surface can hardly be reconstructed as well as built according to the lowest resolution of the AM technologies. For that reason, the fracture surface shall be adjusted to the existing artifact by subtractive post-treatment. Second, distortion of the built fragment during sintering must be avoided and, third, the glaze shall be adjusted in the degree of whiteness or colour to the original artifact and must not wet the fracture surface during glaze firing.