New Test Method for Cohesive Index Flowability Parameter of Metal Powders Using a Rotating Drum Rheometer
1. Scope
1.1 This test method covers the determination of the cohesive index as an inverse indicator of the flowability of metal powders.
1.2 Units - With the exception of the values for mass and volume, for which the use of the gram (g) and the cubic centimetre (cm3) units is the long-standing industry practice, the values in SI units are to be regarded as standard.
1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.
Keywords
cohesive index; flow; flowability; metal powders; rotating drum; spreadability
Rationale
Additive Manufacturing processes such as Powder Bed Fusion (PBF) and Binder Jetting Technology (BJT), as well as conventional Powder Metallurgy (PM) processes, require knowledge of the flowability of the powders used in those processes, affecting spreadability and die filling. Knowledge of the cohesive index of a powder can be used to assess flowability. Powder manufacturers can use the cohesive index to determine applicability and quality of their materials for those processes. Users of powders for producing solid objects can use the cohesive index flowability parameter to determine powder feed rates and spreading rates in their processes for producing solid objects from powders.