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| Naji, M. |
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| Motta, Antonella |
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| Aletan, Dirar |
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| Mohamed, Tarek |
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| Ertürk, Emre |
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| Taccardi, Nicola |
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| Petrov, R. H. | Madrid |
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| Alshaaer, Mazen | Brussels |
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| Bih, L. |
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| Casati, R. |
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| Kočí, Jan | Prague |
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| Kalteremidou, Kalliopi-Artemi | Brussels |
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| Azam, Siraj |
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| Ali, M. A. |
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| Rančić, M. |
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| Azevedo, Nuno Monteiro |
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| Landes, Michael |
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| Rignanese, Gian-Marco |
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Jenkins, Michael
University of Birmingham
in Cooperation with on an Cooperation-Score of 37%
Topics
Publications (7/7 displayed)
- 2024Re-use of polyamide-12 in powder bed fusion and its effect on process-relevant powder characteristics and final part propertiescitations
- 2024The effect of powder re-use on the coalescence behaviour and isothermal crystallisation kinetics of polyamide 12 within powder bed fusioncitations
- 2018Analysis of the failure of a PPS polymer cycling support:citations
- 2017Co2 Assisted blending of poly(lactic acid) and poly(ε-caprolactone)citations
- 2014Production of biodegradable foams using supercritical CO2citations
- 2012A Comparison of the use of FTIR spectroscopy with DSC in the characterisation of melting and crystallisation in polycaprolactonecitations
- 2011Active screen plasma surface modification of polycaprolactone to improve cell attachment.citations
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article
The effect of powder re-use on the coalescence behaviour and isothermal crystallisation kinetics of polyamide 12 within powder bed fusion
Abstract
Polymer powder bed fusion (PBF) is becoming increasingly popular for the fabrication of lightweight, high-performance parts, particularly for medical and aerospace applications. This study investigates the effect of powder re-use and material aging on the coalescence behaviour, melt flowability, and isothermal crystallisation kinetics of polyamide-12 (PA-12) powder. With increased powder re-use, a progressive reduction in melt flowability and material coalescence is observed; at 200 °C, the particle consolidation time increases from 15 s in virgin powder to 180 s in powder recovered from build 6. The observed changes in the behaviour of PA-12 were attributed to polycondensation and cross-linking; these aging phenomena also create structural defects, which hinder the rate and extent of primary crystallisation. At an isothermal crystallisation temperature of 165 °C, the crystallisation half-time increased from 12.78 min in virgin powder to 23.95 min in powder re-used across six build cycles. As a result, the commonly used Avrami model was found to be unsuitable for modelling the crystallisation behaviour of aged PA-12 powder, with the coefficient of determination (R<sup>2</sup>) reducing from >0.995 for virgin powder to as low as 0.795 for reused powder. On the other hand, an alternative method, the Hay model, is able to successfully track full phase transformation within re-used powder (R<sup>2</sup> >0.99). These results highlight the importance of selecting the most appropriate model for analysing the crystallisation kinetics of PA-12 powder re-used across multiple build cycles. This understanding is crucial for obtaining the strong mechanical properties and dimensional precision required for the fabrication of functional, end-use parts within PBF.