Effect of 3D printing angle on microstructure and mechanical properties of silica ceramic cores by stereolithography
Authors: Yue Gu, Wen-yan Duan, Gong Wang, Bing-shan Liu, Xiao-dong Liu, Shan Li
Ceramic cores fabricated by stereolithography exhibit great potential in casting turbine blades. Previous research on ceramic core molding was primarily conducted using vertical printing techniques, which not only resulted in lengthy molding durations but also compromised the mechanical strength. In this work, silica (SiO2) ceramic cores, with fine complex geometric shapes, were fabricated using 65vol.% ceramic slurry by digital light processing (DLP) with different printing angles. Printing angles significantly impact the surface accuracy, shrinkage, printing efficiency of green bodies, as well as the microstructure and mechanical properties of sintered ceramic core samples. As the printing angle in the green body increases, the bonding area decreases, surface roughness on the XY plane worsens, shrinkage in the Z direction becomes more pronounced, and the printing efficiency declines. Similarly, an increase in the printing angle in the sintered body leads to a reduction in bending strength. At a printing angle of 30°, the printing time is reduced to half of that at 90°, which improves the molding efficiency. Meanwhile, the obtained bulk density of 1.71 g·cm-3, open porosity of 24%, and flexural strength of 10.6±1 MPa can meet the requirements of sintered ceramic cores. Therefore, designing and optimizing the printing angles can achieve the balance between shrinkage, printing efficiency, and flexural strength.
