Grants and Contributions:

Grant or Award spanning more than one fiscal year (2017-2018 to 2018-2019).

Powder Bed Fusion is a Additive Manufacturing technique based on the repeated spreading and melting of thinx000D
layers of powder. As the technology evolves from the research to production, the importance of quality controlx000D
of finished parts increases. The relationships between powder feedstock, spreading dynamics and defectx000D
formation are still not fully understood, but the current understanding is that that powder voids formed afterx000D
spreading can seed defects in the finished part. Thus, high quality powders must have properties which enablex000D
the spreading of dense, homogenous layers, free of voids and segregation. These properties must be maintainedx000D
throughout the powder lifetime, which can include recycling, handling and extended storage periods. Despitex000D
the importance of powder spreadability, no universal description or standard for quantitative spreadabilityx000D
exists. Currently, AM powder is characterized by tests which capture some, but not all, of the spreading-relatedx000D
properties, while new AM-specific standards are being proposed.x000D
This proposal concerns a joint investigation between McGill University and Advanced Powders andx000D
Coatings(AP&C) to understand the strengths and weaknesses of characterizing powder spreadability using thex000D
Freeman Technology FT4 powder rheometer. Compared to conventional, gravity-based measurements like thex000D
Hall flow meter, the data generated from the FT4 should should be more representative of spreading-relatedx000D
properties because of the ability to apply precise compressive, tensile and shear forces to the powder bulk.x000D
Whether FT4 test parameters can be matched to specific powder spreading techniques will be determined overx000D
the course of this project. If the FT4 can accurately resolve properties related to spreading, the instrument willx000D
be used to evaluate new powder production techniques as well as support the quality management systems ofx000D
AP&C and their customers.