Multiple-material powder bed fusion machine development: reducing cross-contamination between materials

Powder bed fusion is an additive manufacturing technology capable of producing fully dense, high strength parts with complex geometries. However, it is currently only able to fabricate parts comprised of a single material. Multiple-material capabilities would allow for an added level of design complexity and the matching of material properties to the functional requirements of a part. In order to achieve this, a full redesign of the current powder deposition system is required. Previous attempts to implement multiple-material powder deposition systems encountered issues with controlling the dimensional accuracy in the build direction and crosscontamination between materials. This research integrates an angled blade leveling mechanism along with a nozzle-based powder deposition system to solve these problems. A design of experiments was run to identify significant leveling parameters and to quantify material crosscontamination. A deposition and leveling system that creates a uniform height multiple-material powder bed with no significant cross-contamination of materials is demonstrated.