Impact of Saturation, Layer Thickness and Part Orientation on Green Strength in Metal Binder Jetting Additive Manufacturing of Powder Feedstock Obtained from Spray Forming

Low green strength of binder-jetted parts can lead to potential damage during depowdering and thus complicates green part handling. Understanding and optimizing green strength is therefore essential for the overall control and repeatability of the process. This study systematically investigates the effect of different saturation levels, layer thicknesses and part orientation on the mechanical properties, via compression testing, of binder-jetted cylindrical green parts. The results indicate excellent suitability of the spray-formed powder as binder jetting feedstock due to the uniform spherical particle morphology and high flowability. Mechanical testing indicated that higher binder saturation levels and loading direction perpendicular to the build direction are found to improve the compressive green strength, whereas the layer thickness only has a minor influence. The maximum compressive green strength was achieved as 7.67 MPa on average under the condition of 120% saturation and 90 µm layer thickness.