2024-01-11 スイス連邦工科大学ローザンヌ校(EPFL)
◆LPBF技術の特有の課題に対処し、製造プロセスの信頼性向上と製品品質の向上をもたらす画期的な解決策として期待されています。
＜関連情報＞
- https://actu.epfl.ch/news/laser-additive-manufacturing-listening-for-defec-7/
- https://www.nature.com/articles/s41467-023-43371-3
音と光の調和： X線イメージングがレーザー溶融中の確率的な領域間不安定性の音響シグネチャーを発見(Harmonizing sound and light: X-ray imaging unveils acoustic signatures of stochastic inter-regime instabilities during laser melting)
Milad Hamidi Nasab,Giulio Masinelli,Charlotte de Formanoir,Lucas Schlenger,Steven Van Petegem,Reza Esmaeilzadeh,Kilian Wasmer,Ashish Ganvir,Antti Salminen,Florian Aymanns,Federica Marone,Vigneashwara Pandiyan,Sneha Goel & Roland E. Logé
Nature Communications Published:05 December 2023
DOI:https://doi.org/10.1038/s41467-023-43371-3
Abstract
Laser powder bed fusion (LPBF) is a metal additive manufacturing technique involving complex interplays between vapor, liquid, and solid phases. Despite LPBF’s advantageous capabilities compared to conventional manufacturing methods, the underlying physical phenomena can result in inter-regime instabilities followed by transitions between conduction and keyhole melting regimes — leading to defects. We investigate these issues through operando synchrotron X-ray imaging synchronized with acoustic emission recording, during the remelting processes of LPBF-produced thin walls, monitoring regime changes occurring under constant laser processing parameters. The collected data show an increment in acoustic signal amplitude when switching from conduction to keyhole regime, which we correlate to changes in laser absorptivity. Moreover, a full correlation between X-ray imaging and the acoustic signals permits the design of a simple filtering algorithm to predict the melting regimes. As a result, conduction, stable keyhole, and unstable keyhole regimes are identified with a time resolution of 100 µs, even under rapid transitions, providing a straightforward method to accurately detect undesired processing regimes without the use of artificial intelligence.
