A Method for Measuring Powder Bed Density in Binder Jet Additive Manufacturing Process and the Powder Feedstock Characteristics Influencing the Powder Bed Density
Powder bed additive manufacturing involves layer-by-layer spreading of powders before melting, sintering or binding them. Traditionally apparent and tapped density measurements have been carried out to get an estimate of the powder bed density. Powder bed density is especially important in the case of binder-jet additive manufacturing where sintering is carried out as one of the steps to achieve full densification. During densification, shrinkage occurs. The extent of shrinkage depends upon the powder bed density. Thus, it is important to understand the role of powder feedstock on controlling the powder bed density. In the present paper, we have developed a technique to measure the powder bed density. We also used different powder feedstock materials to understand the role of powder size distribution and morphology on the powder bed density. The detailed results are presented.