ERI: Study of Powder Spreading Behavior for Additive Manufacturing Applications in a Novel Test Bed Environment

High quality metal powder suitable for additive manufacturing is a key factor for producing defect-free parts for mission critical applications. Existing powder characterization methods are reported to have limited applications in additive manufacturing. This is because they do not directly address powder spreadability, a critical but not well understood metric.

This Engineering Research Initiation (ERI) project aims to fill this research gap by designing a testbed to better define and measure powder spreadability. Novel measurement methods, which determine the three-dimensional topography of spread powder layers, will be developed and advanced data processing solutions will be used to distill these complex measurements into easily interpreted summary metrics that directly imply powder quality and suitability for the additive manufacturing process.

If successful, the researched testbed and metrics can facilitate the monitoring of the powder spreadability for virgin powder supplies as well as re-used and recycled powder. The expected outcomes will have a significant impact on the quality testing methods used in the standard communities and manufacturing industry.

Spreadability is a poorly understood characteristic of powder which may lead to heterogeneity in the powder bed and thus lack of fusion in manufactured components. This correlation has been difficult to establish without a rigorous study of spreadability and supporting methodology for measuring the property of spreadability. The objective of work associated with this project is to interrogate the physics of powder spreading to define the main process variables and their influences on spreading behavior.

Spreadability will be quantified via summary metrics derived from the physical topography of the formed powder bed via adapted surface texture analysis methods. A novel experimental test bed employing fringe projection profilometry to measure powder bed topography will be utilized. This will overcome existing limitations of powder characterization methods that were developed for powder metallurgy, not additive manufacturing.

A screening experimental design will be applied to identify critical process variables and determine the most effective measures of spreadability. Research results will support the future development of standardized quality testing procedures for metal powder feedstocks that will promote overall process control and the wider adoption of laser powder bed fusion.

The outcomes will impact other powder spreading processes, such as binder jet and selective laser sintering.

This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.