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

Abstract

ABSTRACT 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 of finer powders to produce homogeneous, dense final parts. However, the strong cohesive forces of fine metal powders impair flowability, packing behaviour and thus the properties relevant for powder spreading. This paper investigates the impact of powder condition and spreading parameters on green and sintered density using an Analysis of Variance. Parts from dried and from untreated powder are printed, varying in layer thickness, roller diameter, supply-to-spread ratio, translational and rotational roller speed. Powder drying increases the statistical impact of the spreading parameter and improves the green density, while the sintered density remains unchanged. Layer thickness and roller diameter have the most significant effect. Furthermore, the spreading parameter combinations that resulted in a high green density also provided a high sintered density.