Publications - XARION Laser Acoustics

Applied Sciences 10/2024

Acoustic Emission and Digital Image Correlation-Based Study for Early Damage Identification in Sandwich Structures

Authors:

Aitor García de la Yedra, Igor Erro, et al.

Contents:

Monitoring the quality of complex sandwich structures is difficult with common testing techniques for accessibility reasons
A novel approach to solve this issue is enabled by acoustic monitoring in the ultrasound regime with the Optical Microphone
The results from acoustic monitoring were compared to findings obtained with digital image correlation
It could be shown that early identification of structural damage is possible with the Optical Microphone

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Nature Communications 12/2023

Harmonizing sound and light: X-ray imaging unveils acoustic signatures of stochastic inter-regime instabilities during laser melting

Authors:

Milad Hamidi Nasab, Giulio Masinelli, et al.

Contents:

Laser Powder Bed Fusion Additive Manufacturing (LPBF AM) is a metal additive manufacturing process capable of directly producing intricate three-dimensional metallic components from CAD models
The present work deploys high-speed synchrotron X-ray imaging to scrutinize keyhole melting instabilities in LPBF and correlates these with the process’ acoustic emission (AE)
XARION’s optical microphone was used to measure airborne AE from the interaction zone between laser and material
The transition between conduction, stable keyhole, and unstable keyhole regimes, which leads to porosity formation and other instabilities, can successfully be discerned using the AE data

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SPIE. Photonics West 01/2024

Towards process control by detecting acoustic emissions during ultrashort pulsed laser ablation of multilayer materials

Authors:

C. Lutz, R. Sommerhuber, M. Kettner, C. Esen, R. Hellmann

Contents:

Ultra-short-pulsed laser ablation of thin multilayer materials can be monitored using XARION’s Eta450 Ultra optical microphone
It is possible to monitor the material transition between polymer and copper during laser ablation by observing a broad acoustic frequency spectrum between 100 kHz and 2 MHz in air, and by detecting a sudden change in acoustic energy
A direct correlation was found between increased detected acoustic energy and higher ablation rate

Link

Nature Communications 11/2023

Ultrasonic barrier-through imaging by Fabry-Perot resonance-tailoring panel

Authors:

Chung Il Park, Seungah Choe, et al.

Contents:

Ultrasonic imaging through nearly impenetrable metal barriers or the human skull remains an unresolved challenge
Applying a Fabry-Perot resonance approach and resonance tailoring panels the authors show that ultrasonic transmission through otherwise impenetrable barriers can be achieved
XARION's optical hydrophone (Eta100L Ultra) was employed to capture ultrasonic signals in the experiments
The newly developed method enables almost equivalent image quality as without barriers and has the potential to improve ultrasonic imaging

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Additive Manufacturing 01/2024

Healing of keyhole porosity by means of defocused laser beam remelting: Operando observation by X-ray imaging and acoustic emission-based detection

Authors:

Charlotte de Formanoir, Milad Hamidi Nasab, et al.

Contents:

In Laser Powder-Bed Fusion (LPBF) the unpredictable formation of defects such as pores can lead to compromised mechanical properties
Using XARION’s optical microphone a strategy for monitoring in-situ healing of pores through laser remelting was implemented
Acoustic signals acquired during laser remelting are temporally synchronized and analyzed with X-ray images to identify acoustic signatures of the pore healing event
The approach presented in this paper enables precise monitoring of defect healing during the LPBF process without the use of elaborate machine learning algorithms

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Nature Photonics 10/2023

Acousto-optic modulation of gigawatt-scale laser pulses in ambient air

Authors:

Yannick Schrödel, Claas Hartmann, et al.

Contents:

XARION's optical microphone has been used to measure high-intensity ultrasonic fields
Schrödel et al. from DESY Hamburg showed deflection of gigawatt-scale laser pulses in air
Controlling coherent light is crucial in many fields, but modern photonics faces limitations from factors like wavelength and high optical powers
Using ultrasound-tailored gaseous media to efficiently deflect laser pulses offers new possibilities for resilient optical elements
To measure and characterize the ultrasound fields used for deflection, XARION’s Optical Microphone was used

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Composite Structures 10/23

Low-velocity impact behaviour of biocomposite laminates reinforced by flax, basalt and hybrid fibres at various temperatures: Analytical, numerical and experimental results

Authors:

Valentina Giammaria, Simonetta Boria, Josef Pörnbacher, et.al.

Contents:

The impact behavior of bio-composites reinforced with flax, basalt and hybrid fibers was investigated
XARION’s LEA method was used to assess the internal damage of the composites after impact

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Wood Material Science & Engineering 05/2023

Supervised classification of wood species during milling based on extracted cut events from ultrasonic air-borne acoustic signals

Authors:

Mehieddine Derbas, Stephan Frömel-Frybort, Christian Laaber, Hans-Christian Möhring, Martin Riegler

Contents:

Monitoring during wood processing is gaining momentum in order to increase efficiency and enable adaptive manufacturing
Acoustic monitoring is particularly suited for the cutting/milling process
Derbas et al. developed a Machine Learning model to distinguish between wood species with up to 93% accuracy using single-cut events

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Optics and Laser Technology 04/2023

A comprehensive study on water jet guided laser micro hole drilling of an aerospace alloy

Authors:

Levent Subasi, Mustafa I. Gokler, Ulas Yaman

Contents:

Water-Jet Guided Laser Drilling is a process particularly suited for manufacturing of thin and long holes in metals
In this study, the Optical Microphone has proven to be a suitable sensor for monitoring the hole depth and the moment of hole breakthrough in real-time

Link

12th International Electric Drives Production Conference (EDPC) 01/23

Inline Process Monitoring of Hairpin Welding Using Optical and Acoustic Quality Metrics

Authors:

Markus Omlor, Johannes Reith, et.al.

Contents:

XARION´s Optical Microphone was used to capture airborne ultrasound generated during the hairpin welding process
A multitude of welds were performed under varying quality-affecting parameter conditions, such as positioning misalignments or focal height and laser power deviations
It was found that the real-time ultrasound emission could be utilized as an early indicator for predicting the important quality criterium of final cross-sectional area of connection

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