Laser Stereolithography for Zirconia Ceramic Fabrication and Its Debinding and Sintering Process

Abstract

Due to good mechanical properties, biocompatibility and corrosion resistance, zirconia ceramic has been widely used in dental repairing. However, the present technologies for zirconia ceramic fabrication based on stereolithography have some drawbacks, such as low fabrication accuracy, low debinding efficiency, high shrinkage, and shrinkage anisotropy. In order to solve these problems, a kind of hybrid resin was prepared by using different monomers with different functionalities, and then zirconia ceramic slurry with solid content of 55% (volume percentage) was prepared by using this hybrid resin, which dispersed organic matter pyrolysis interva, promoting debinding efficiency and avoiding crack. Besides, effect of laser power and scanning speed to the curing unit shape were studied, the optimum laser power of 670 mW and scanning speed of 2500 mm/s were selected to meet requirments of fabrication accuracy and efficiency. In addition, effects of scanning line space and scanning line width compensation to horizontal dimension accuracy and slicing thickness to the stacking dimension accuracy were studied. Optimum process scanning line space of 0.08 mm, scanning line width compensation of 0.10 mm, and slicing thickness of 0.03 mm were determined. Meanwhile, the green part was debinded in nitrogen atmosphere, which reduced pyrolysis rate of organic matter, performed a further improvement of debinding efficiency and green part cracking. At last, the debinded part was sintered. The plane and stacking direction shrinkages of the sintered part are (18.26±0.10)% and (19.20±0.13)%, respectively. All these results demonstrated that the shrinkage is reduced and the shrinkage anisotropy is reduced obviously, which provides basis for application in dental repairing.