Evaluation of the metal additive manufacturing process through the study of the recyclability of metal powders and in-situ monitoring

Quinn, Paul (2024) Evaluation of the metal additive manufacturing process through the study of the recyclability of metal powders and in-situ monitoring. Doctoral thesis, SETU Waterford.

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Abstract

Laser powder bed fusion (L-PBF) processes are becoming frequently applied within a wide range of industries. Enabling the production of complex, high-value components, within the medical device and aerospace industries where regulations drive the requirement for stringent quality control. Powder material used in the L-PBF process can be costly, and as it is rare for a full batch of virgin powder to be used in one build, it is frequently recycled for subsequent builds. Therefore, it is useful to characterise both the powder material being recycled and the final printed component properties. Characterisation of the recycled powder and the parts allows the feasibility of powder recycling to be assessed. Methods required to extend the utility of a single batch of powder through a process called powder rejuvenation are also investigated. Thus, quantifying the effectiveness of allowing a previously recycled powder to be utilised further in the L-PBF process. With an understanding of the effect of recycling and rejuvenation processes on the powder and the manufactured part properties an empirical model for the prediction of the part density and surface roughness are developed. This allows the user to input the current powder characteristics to predict the manufactured part qualities. Furthermore, the ability to monitor components as they are being built layer-by-layer enables their quality to be assessed. Using in-situ monitoring, the identification of defects as well as measurement of the layers throughout a build allows for greater quality control, as well as a reduction in the requirement for ex-situ measurement. Results from this work provide L-PBF operators with understanding of the effect that recycled and rejuvenating of powders have on the quality of the components produced. Also providing a method to monitor the component layer-wise throughout the process. This will facilitate a more controlled use of L-PBF within the highly regulated industries.

Item Type:	Thesis (Doctoral)
Uncontrolled Keywords:	Metal additive manufacturing process
Departments or Groups:	*NONE OF THESE*
Divisions:	School of Engineering > Department of Engineering Technology
Depositing User:	Derek Langford
Date Deposited:	29 Apr 2024 15:38
Last Modified:	29 Apr 2024 15:38
URI:	https://repository.wit.ie/id/eprint/7778

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