Assessment of geometrical variability in 3D printed ZrO2: Effects of printing and thermal post-processing

3D printing is developing rapidly and enables the production of parts manufactured using different materials. These includes zirconium dioxide (ZrO2), which can be of particular interest for bone tissue engineering and implantology. However, highly accurate part-dimensions are a must for these applications, which is why this study addresses geometrical deviations which occur during the printing process and thermal post-processing. Six sets of test geometries with 50 individual features were 3D printed with two different ZrO2 slurries (3 mol% yttria-stabilized ZrO2) and scanned with a profilometer. After debinding and sintering, the profilometer scan was repeated and the deviations and shrinkage factors were determined. A notable difference is observed when the same ceramic is processed using two different slurries. For instance, one used ceramic slurry, LithaCon 210, exhibits shrinkage factors of shrXY=21.2±3.4% (n=78) and shrZ=23.6±0.54% (n=24) for protruding structures, while the other ceramic slurry, LithaCon 280, shows shrinkage factors of shrXY=21.7±3.3% (n=78) and shrZ=24.5±0.55% (n=24). Geometric deviations differed for intruding (like holes and slots) and protruding (like pillars) geometries, being more pronounced in case of intruding geometries, especially where printing overhangs occur. Although the shrinkage during sintering needs further investigation, these experimental findings are a good starting point to validate and refine simulation models for shrinkage and improve production processes of 3D printed ceramics.