Hydration Deformation Behaviors of Scaffolds of Tricalcium Silicate/Tricalcium Aluminate Mixtures Printed Using the Fused Deposition Modelling (FDM)

Abstract

3D printing technology has advanced rapidly over the last decade. However, for ceramic materials, drying and sintering steps are required after printing, and excessive shrinkage that occurs during these steps is a major factor that has hindered the development of the ceramic 3D printing technology. In this study, a non-sintering ceramic 3D printing method was developed using a hydraulic material to overcome the size deformation issue encountered during the post-processing of a scaffold-type printed green body. The deformation characteristics occurring during the curing process were confirmed. Tricalcium silicate (C3S) and tricalcium aluminate (C3A), which are well-known hydraulic materials, were selected. They were prepared into a printable paste by mixing with a viscous hydrophilic oil such as polyethylene glycol and polypropylene glycol, which helped the printout survive without collapse while it was cured. The scaffold was printed by Fused Deposition Modelling (FDM), which is the simplest and most economical printing method, and was cured by immersion in a water bath. The hydrated scaffold of the C3S/C3A mixture exhibited a smaller strain than the scaffold of the single materials, and the deformation amount depended on the printing direction. Remarkably, a scaffold with the smallest deformation, of less than 1%, and the highest compressive strength was obtained with a C3S/C3A mixing ratio of 65/35.