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Lookup NU author(s): Sina Zinatlou Ajabshir, Dr Colin HareORCiD
This work is licensed under a Creative Commons Attribution 4.0 International License (CC BY 4.0).
© 2024 The Society of Powder Technology Japan. This study investigates the spreadability behaviour of four different polymeric materials, namely Polyamide 6, Polyamide 6 Black, Polypropylene, and Thermoplastic Polyurethane, under different spreading speeds (30 and 3 mm/s) and powder bed temperatures (25, 80, 110 °C) using a purposely developed experimental apparatus. Macroscopic and microscopic images of the powder layer were taken after completing the powder spreading step. A thresholding-based image processing method was utilised to evaluate the fraction of the bed area not covered by particles (NCF), and the standard deviation of pixel intensities in grayscale images (SDG) was calculated to evaluate powder layer quality in macroscopic images. NCF and SDG can provide quantitative evaluation of the quality of the spread layer, NCF in a logarithmic scale ranking and SDG in a linear scale ranking. A wavelet analysis technique was developed on microscopic panorama images obtained with grazing light to characterise the surface roughness of the layer. Results indicate that the spreadability generally worsens much more significantly than powder flow properties at increasing temperatures and, remarkably, that flowability and spreadability are unrelated. As expected, the temperature effect on powder spreading changes for the different powders are mostly governed by the approach to the powder melting temperature. Minor effects on the final layer quality were also observed at changing spreading speed.
Author(s): Zinatlou Ajabshir S, Sofia D, Hare C, Barletta D, Poletto M
Publication type: Article
Publication status: Published
Journal: Advanced Powder Technology
Year: 2024
Volume: 35
Issue: 4
Print publication date: 01/04/2024
Online publication date: 28/03/2024
Acceptance date: 22/03/2024
Date deposited: 13/06/2024
ISSN (print): 0921-8831
ISSN (electronic): 1568-5527
Publisher: Elsevier BV
URL: https://doi.org/10.1016/j.apt.2024.104412
DOI: 10.1016/j.apt.2024.104412
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