Effect of printing orientation on flexural strength of parts from binder jetting

In this work, the effect of printing orientation on the flexural strength of the parts from binder jetting was investigated. Flexural samples were printed with six different orientations using a commercially available alumina powder. The printed samples were then cured, depowdered, debound, and sintered. Afterward, the flexural strength of the samples was measured with three-point bending tests. The results showed that the flexural strength varied significantly from 82.8 ± 5.3 MPa to 151.6 ± 4.0 MPa with different printing orientations. Archimedes method and X-ray computed tomography were then used to evaluate the bulk density and defect distribution of the samples, as an attempt to explain their flexural strengths. The Archimedes method showed there was no considerable difference in the bulk density among samples printed with different orientations. However, the X-ray computed tomography revealed significantly different defect distributions with different printing orientations, which was expected to be the cause for the different flexural strengths.