Sintering anisotropy of binder jetted 316L stainless steel: part I – sintering anisotropy

In Binder Jetting (BJ) Additive Manufacturing (AM), green components are usually subjected to sintering process to reach required properties. Owing to the inherent low green density, binder jetted (BJ) parts undergo shrinkages up to 20%. In addition, anisotropic dimensional evolution during sintering is characteristic for BJ, generally caused by the specifics of the arrangement of particles during the printing process. In this study, the multi-axial dimensional evolution of 316L stainless steel cubic samples (10 × 10 × 10 mm3), manufactured using BJ, was characterised by dilatometry experiments. Dilatometry tests were conducted up to sintering temperatures of 1300°C and 1370°C, with a heating rate of 10°C/min and 5°C/min, respectively. Dilatometry results and final dimension measurements showed anisotropic shrinkage behaviour during sintering with about 15% larger shrinkage along the building direction. Shrinkages along the other two orthogonal directions were relatively similar, but a slightly larger final shrinkage along the printhead movement direction was observed. Relative density of 85.0% and 96.4% was obtained after sintering tests at 1300°C and 1370°C, respectively.