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Process Monitoring

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
Link

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
Link

Proceedings of LANE 2022 Erlangen 09/2022

Monitoring of remote laser processes using air-coupled ultrasound

Authors:

R. Sommerhuber, M. Kettner

Contents:
  • XARION’s optical microphone was used for contact-free monitoring of laser processes by comparing the acoustic emissions of the process to known reference signals
  • In this paper, this monitoring method was shown to be able to detect defects and irregularities in the welding of metal sheets and of direct copper bonded substrates
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Int. J. Adv. Manuf. Technology 08/2022

Real-time measurement of laser beam characteristics for a waterjet-guided laser machine

Authors:

Levent Subasi, Mustafa I. Gokler, Ulas Yaman

Contents:
  • Waterjet-guided laser machining, a novel process used for precision cutting and drilling, was monitored using XARION’s optical microphone
  • Various process parameters, such as the laser power in the water, could be measured more precisely than with other real-time monitoring methods investigated
Link

Tech Briefs 09/2021

Monitoring Additive Manufacturing with an Optical Microphone

Authors:

Martin Ursprung, Ryan Sommerhuber, et.al.

Contents:
  • XARION’s ultrasound sensor enables process monitoring of Additive Manufacturing processes
  • Defects such as the formation of cracks can be detected during Laser Metal Deposition and Powder Bed Fusion processes
  • Critical process parameters can be observed during Wire Arc Additive Manufacturing
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Materials & Design 08/2021

Mutual comparison of acoustic, pyrometric and thermographic laser powder bed fusion monitoring

Authors:

Kai Gutknecht, Michael Cloots, et. al.

Contents:
  • The process monitoring capabilities of three distinctive sensors (XARION’s optical microphone, a pyrometer and a thermographic camera) were compared for laser powder bed fusion metal additive manufacturing
  • The optical microphone presents a sensitivity up to 40 times higher than the thermographic camera and is 15 times more sensitive than the pyrometer
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Proceedings of LANE 2020 Erlangen 

In situ process monitoring by optical microphone for crack detection in Laser Metal Deposition applications

Authors:

Camilo Prieto, Roberto Fernandez, et.al.

Contents:
  • Contact-free crack detection in Laser Metal Deposition (LMD) applications in collaboration with AIMEN successfully documented
  • XARION’s optical microphone, Eta250 Ultra, enabled real-time monitoring of crack and process signals of additive manufacturing applications
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Proceedings of SPIE LASE 2020 San Francisco 

Air-coupled membrane-free optical microphone and optical coherence tomography keyhole measurements to setup welding laser parameters

Authors:

Nicolas Authier, Enzo Touzet, et. al.

Contents:
  • Accurate measurements of the welding depth could be demonstrated with XARION's sensor by the French Alternative Energies and Atomic Energy Commission (CEA)
  • The combination of Optical Coherence Tomography with airborne ultrasound data from an Optical Microphone is a promising match for in-line monitoring of laser welding processes
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Bachelor Thesis University Ravensburg-Weingarten 

Acousto-optical Process Control for Laser Ablation and Laser Welding

Authors:

Chen Peng

Contents:
  • The optical microphone has proven effective and invaluable as a measurement instrument during laser processes.
  • The measurements obtained are useful in:
    • the automated calibration of the optimum focus spot of a laser beam,
    • controlling the laser ablation quality in a production line without modifying the workpiece, and
    • identifying keyhole formation (or lack thereof) during laser welding processes. 
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