Assessment of the Achievable Dimensional Tolerances in 17-4PH Stainless Steel Parts Fabricated by Metal Binder Jetting

This work aims at evaluating the dimensional precision and the accuracy achievable through the Metal Binder Jetting Additive Manufacturing process. An artifact was designed, and 36 replicates were produced using a 17-4PH stainless steel powder aiming at evaluating different feature sizes. The dimensions of the samples were measured by a coordinate measuring machine (CMM) before and after sintering. At green state, the distribution of measured dimensions parallel to the building direction was centered on the nominal dimension, while the distribution of measured dimensions parallel to the building plane was shifted from the nominal ones. Dimensions of cavities were found to be significantly smaller than nominal ones (Z position for fundamental deviation), whereas the dimensions of outer features were larger than the nominal sizes probably on the reason of excessive binder saturation. The dimensional precision ranged from IT9 to IT11. After sintering, the inaccuracy increased with the distance of samples from the building plane, in turn related to non-uniform shrinkage on sintering. Additionally, sintering determined worsening in the dimensional precision, which ranged from IT11 to IT15.