Evaluation Of Porosity In Metal Binder Jetting Due To Binder Application By Using X-ray CT

Metal Binder Jetting (MBJ) offers many advantages, as the material variety also includes non-weldable materials and is capable of higher build rates compared to other powder bed-based processes, which makes the process interesting from an economical perspective. In contrast to other powder bed-based processes the binder application is unique. The aim of this work is to characterize and analyse the porosity distribution of the green parts by computed tomography. The parameters binder saturation and layer thickness are varied. These results show that binder application leads to porosity in green and sintered parts due to droplet impact. A higher binder saturation can compact the particle structure in the green part due to capillary forces. This also results in a better inter-layer bonding and leads to a lower anisotropy of the shrinkage. Resulting particle segregation in the powder bed & green part are due to powder application by a counter rotating roller.