Powder condition and spreading parameter impact on green and sintered density in metal binder jetting

Metal binder jetting is a high throughput additive manufacturing process of growing interest.The progress is driven by improvements in machine technology, enabling the processing offiner powders to produce homogeneous, dense final parts. However, the strong cohesiveforces of fine metal powders impair flowability, packing behaviour and thus the propertiesrelevant for powder spreading. This paper investigates the impact of powder condition andspreading parameters on green and sintered density using an Analysis of Variance. Partsfrom dried and from untreated powder are printed, varying in layer thickness, rollerdiameter, supply-to-spread ratio, translational and rotational roller speed. Powder dryingincreases the statistical impact of the spreading parameter and improves the green density,while the sintered density remains unchanged. Layer thickness and roller diameter have themost significant effect. Furthermore, the spreading parameter combinations that resulted ina high green density also provided a high sintered density.