Researchers from De Montfort University, Leicester, UK, are said to have successfully correlated the quality of additively manufactured polyamide specimens with powder properties measured by the FT4 Powder Rheometer® from Freeman Technology, Tewkesbury, Gloucester, UK. While this study focuses on polymeric powder, the technology is also applicable to metal powder feedstocks.
Build trials usually determine which powders are suitable for which projects, but these can be costly and time-consuming. The latest research from De Montfort has reported that the packing efficiency and flowability of the associated powder feedstock correlate to the dimensional accuracy, tensile strength and surface roughness of the resultant additively manufactured part. The qualities of the feedstock can be gauged via the measurement and bulk dynamic powder properties with the FT4 Powder Rheometer.
In the study, two commercial polyamide powders of similar particle size and morphology were used to produce five powder blends for testing. Measurements of dynamic properties – Basic Flowability Energy and Aeration Ratio – were said to clearly differentiate the blends with respect to flowability, while Conditioned Bulk Density values provided complementary insight on packing efficiency. Print trials with the powder blends using a commercial Laser Beam Powder Bed Fusion (PBF-LB) Additive Manufacturing system produced samples that varied considerably with respect to mechanical properties. Observed variability was rationalised with reference to the measured powder properties and correlations were established for key properties.
The whitepaper – ‘Learning to predict print quality from powder properties’ – is available here, in full.