Search for: All records

Binder jetting is a powder bed additive manufacturing process where an object is created by depositing liquid binder onto the surface of powder, selectively binding particles in each layer. The quality of the as-printed parts is influenced not only by process parameters such as layer thickness, binder saturation, print speed, and drying time but also by the location within the build box. This study highlights the location-dependent nature of green density and dimensional accuracy in the as-printed samples, and the observed trends are thoroughly discussed. A conventional powder spreading using a single roller was compared with a double roller to maximize powder packing and bed uniformity prior to binder jetting process. The significance of these observations lies in their impact on densification behavior, shrinkage, and the final geometry of the printed part. 

Study examines binder deposition methods (bulk vs. selective printing) and sintering atmospheres (vacuum vs. H2) on binder jetted 316 L stainless steel components. The density of the H2-sintered specimens was found to be lower (up to 5%) compared to the vacuum-sintered parts with the final density of 99.7%. Grain size analysis indicated smaller grains in the H2-sintered parts (∼26 μm) compared to vacuum-sintered condition (∼33 μm) in the bound area which could be attributed to the presence of residual pores that impeded grain growth. The H2-sintered specimens exhibited an elongation of 25% and an ultimate tensile strength (UTS) of 460 MPa, whereas the vacuum-sintered parts displayed an elongation of 70% and a UTS of 550 MPa. Fractography analysis using microscopy and micro-computed tomography revealed ductile fracture in the vacuum-sintered samples, while the H2-sintered parts exhibited a combination of brittle and ductile fracture due to remnant pores in the microstructure.