Effect of the Particle Size Distribution of Irregular Al Powder on Properties of Parts for Electronics Fabricated by Binder Jetting

The present work analyzed the influence of the particle size of irregular aluminum powder on the properties of Binder-Jetting-printed parts, which can be used as electronic components. Powders of various particle sizes as well as blends in the ratio of 73–27 wt.% or 27–73 wt.% of coarse to fine powder particles were used. The parts were printed with constant parameters, such as a layer thickness of 120 µm, roller traverse speed of 10 mm/s, and binder saturation of 80%. For parts made of individual blends, analysis of the XRD, density, porosity, surface roughness, and dimensional changes in X, Y, and Z axes after the sintering process was conducted. The results confirmed the trend of smoothing the surface of 3D-printed parts with a reduction in the size of the powder particles used. The best results in terms of surface roughness were obtained for powder in which coarse particles (73%) had 50 µm and fine particles (27%) had 20 µm. However, the incorporation of coarser particles in an amount of 27 wt.% (AL160) to the fine-grained powder base (ALC100) allowed for the obtaining of details with higher density, lower total porosity, and relatively low surface roughness. The combination of these two powder particle sizes allowed the fine powder to fill the voids between the larger particles, resulting in properties that represent an excellent relationship between density, porosity, and surface quality. The research results indicate that the three-dimensional parts produced by Binder Jetting technology, through the phenomenal thermal conductivity of aluminum, can be successfully used as electronic components, such as heat sinks or transistor housings.