Insights into mechanisms governing the print-bed characteristics in binder jet additive manufacturing

While evaluating the overall structural characteristics of print beds in Binder Jet Additive Manufacturing (BJ-AM) is crucial, it fails to capture localized variations that significantly influence the sintering behaviour and final properties of printed samples. This study leverages the Discrete Element Method (DEM) to investigate microstructural heterogeneities in BJ-printed powder beds, with a particular focus on the impact of particle size distribution (PSD) on properties such as green density and local particle size variations along the build direction. The findings reveal that structural non-uniformities in BJ powder beds arise both between and within individual print layers. The inter-layer variations are governed by local ‘particle mobility’ and ‘size ratio’ effects, while intra-layer structures are influenced by particle ‘ordering’ phenomena and packing arrangements. The study provides valuable insights into the intricate relationships between BJ-AM process parameters and powder bed microstructures, facilitating the development of optimized printing protocols to enhance part quality and performance. • Microstructural variations across the layers in BJ Printed powder beds investigated utilizing DEM. • Feedstock PSD impacts local density and particle size along building direction. • Inter-layer and intra-layer density fluctuations arise from different microstructural mechanisms during printing. • Optimizing initial PSD as a process parameter enhances powder bed structural homogeneity.