Theis Lukas, Duarte Valdemar, Roque João C, Santos Telmo, Martins Rui F
Department of Mechanical and Industrial Engineering, UNIDEMI, NOVA School of Science and Technology, Universidade NOVA de Lisboa, Caparica, Portugal.
Laboratório Associado de Sistemas Inteligentes, LASI, Guimarães, Portugal.
3D Print Addit Manuf. 2024 Jun 18;11(3):e1356-e1365. doi: 10.1089/3dp.2023.0006. eCollection 2024 Jun.
The current process for creating zirconia reconstructions for teeth is time-consuming, expensive, and results in tool wear and raw material waste. An alternative method, near-net shape additive manufacturing capable of producing samples with color gradient is presented as an innovative and more efficient solution. A low-cost robocasting system, which enabled the co-extrusion of two different ceramic inks, was designed and developed. Moreover, hydrogel-based ceramic inks, with rheological properties suitable for the present system, containing commercially available Yttria-stabilized zirconia (white and yellow) powders, were produced. Parts of different color shades and color gradients, with a high aspect ratio and good green body stability, were printed. In addition, precise color measurements were carried out, and co-extruded parts were compared with ultraviolet-C photofunctionalized parts. High fractions of binder in green bodies caused distortions in the samples during air drying and upon sintering. Debinding and sintering at 1500°C yielded parts of relatively low density (4.90-5.09 g/cm) and hardness (500 HV10-1100 HV10). A slightly different sintering behavior was observed for parts of different compositions. Density and hardness increased with the fraction of iron oxide-containing ink.
目前用于制造牙齿氧化锆修复体的工艺耗时、昂贵，且会导致工具磨损和原材料浪费。本文提出了一种替代方法，即近净形增材制造，它能够生产具有颜色梯度的样品，是一种创新且更高效的解决方案。设计并开发了一种低成本的机器人铸造系统，该系统能够共挤出两种不同的陶瓷墨水。此外，还制备了基于水凝胶的陶瓷墨水，其流变特性适用于本系统，其中含有市售的氧化钇稳定氧化锆（白色和黄色）粉末。打印出了具有高纵横比和良好坯体稳定性的不同颜色深浅和颜色梯度的部件。此外，还进行了精确的颜色测量，并将共挤出部件与紫外线-C光功能化部件进行了比较。坯体中高比例的粘结剂在空气干燥和烧结过程中导致样品变形。在1500°C下脱脂和烧结后得到的部件密度（4.90 - 5.09 g/cm）和硬度（500 HV10 - 1100 HV10）相对较低。观察到不同成分的部件烧结行为略有不同。密度和硬度随着含铁氧化物墨水的比例增加而增加。
