| 초록 |
Shrinkage during sintering should be carefully understood to fabricate three-dimensional glass structures using a powder based three-dimensional printing (P-3DP). Although the sintering of glass dependence on time is governed by viscous flow, the effect of the powder characteristics and the process parameters during printing needs to be considered. In this study, we optimized the powder characteristics to fabricate glass structures using P-3DP, and anisotropy during sintering of printed structures were studied. SiO2-B2O3-ZnO system of glass powders were used with different particle sizes and shape (irregular and spherical powders). Cylindrical samples were printed longitudinally and transversely. Sintering condition for as-printed structures was analyzed using a hot stage microscopy. Anisotropy degree was measured by ratio (k) between axial contraction and radial contraction for different sintering time at a certain temperature. Flowability of irregular powders were strongly dependent on the particle size resulting in green density of printed structures, whereas the finer spherical powder showed excellent flowability and the highest green density. Longitudinally printed structures showed greater anisotropy degree than transversely printed structures. Also, structures made with spherical powder showed more isotropic shrinkage behavior (k=0.98) because of the higher green density induced by excellent powder flowability. |
