DE EN

Process Monitoring

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 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
PDF

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
PDF
Wood Material Science

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
Inline Process Monitoring

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
PDF
Real-time measurement of laser beam

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
PDF
XARION powder bed fusion monitoring

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
PDF