Influence of Temperature and Print Orientation on Anisotropic Sintering in Binder Jet SS316L

During sintering, components typically experience dimensional changes and shrinkage because of low green density. This study used dilatometry experiments to analyze the multi-axial dimensional evolution of cylindrical 316L stainless steel samples (6 mm diameter and 5 mm length) fabricated by binder jetting (BJ). Two sintering temperatures (1250, 1390 degrees C) and three printing orientations with respect to the powder bed were investigated. The anisotropic shrinkage ratio was affected by the printing orientation and sintering temperature. The build (Z) direction played a key role in the anisotropic shrinkage behaviour observed in the sintered material. The ratio of shrinkage between the build direction and recoater-printhead directions (>1.10) was higher than the ratio of shrinkage between the recoater and printhead directions (similar to 1.00). High shrinkage in the Z direction was attributed to primitive lines observed perpendicular to the build direction. As the sintering temperature increased from 1250 to 1390 degrees C, the shrinkage ratio increased from 1.10 to 1.21.