We monitor thin disk laser beam welding processes coaxially through the welding optics with a camera that is sensitive in the near-infrared (NIR) spectrum (1200…1700 nm). With this sensor we detect the thermal radiation from the process zone and we can analyze it in real-time during the welding process. From the observed features we monitor the laser weld in respect to various welding faults.
In particular, we analyze the thermal trace of the weld seam and its vicinity. For lap joints the analysis of the thermal trace enables us to detect missing fusion immediately and in real-time. This in-situ online heat flow thermography is a unique method to detect “false friends” during the welding process itself.
REFERENCES
1.
Shao
, J.
, Yan
, Y.
(2005
) Review of Techniques for On-line Monitoring and Inspection of Laser Welding
, J. of Physics: Conf. Series
Vol. 15
(Sensors & their Applications), pp. 101
–107
2.
Kogel-Hollacher
, M.
(2012
) Industrial Application of Quality Control in Laser Materials Processing
: From Lab to Serial Production, AKĹ12 - Technological Conference
, Session 1, Aachen, Germany
3.
Halschka
, M.
, et al (2003
) Machine Vision – The Powerful Tool for Quality Assurance of Laser Welding and Brazing
, Proc. of 22ᵗʰ International Conference of Applications of Lasers and Electro-Optics, ICALEO 2003
, Jacksonville, FL, USA
4.
Dahmen
, M.
, et al (2009
) Detection of Phase Boundaries and Defect Detection in CO2-Laser Beam Welding
, Proc. of LAMP 2009
, Kobe, Japan
5.
Kratsch
, Ch.
, et al (2000
) Coaxial process control during laser beam welding of tailored blanks
, Proc. of SPIE 3888
, San Jose, CA, USA
6.
Braun
, H.
, et al (2011
) Camera-based Laser Beam Welding Sensor in the Near Infrared Spectral Range
, Proc. of 30tʰ International Conference of Applications of Lasers and Electro-Optics, ICALEO 2011
, Orlando, FL, USA
7.
Dorsch
, F.
et al (2012
) NIR-camera-based online diagnostics of laser beam welding processes
, Proc. of SPIE 8239
, San Francisco, CA, USA
8.
Rosenthal
, D.
(1946
) The theory of moving sources of heat and its application to metal treatments
, Trans. ASME
vol. 48
, pp. 849
–865
9.
Kaplan
, A.
(2009
) Keyhole Welding: The Solid and Liquid Phases, in: J.
Doden
(ed.) The Theory of Laser Materials Processing
, pp. 71
–93
, Springer
10.
Jurca
, M.
, Langer
, H.-J.
(2010
) Temperature field measurement as quality assurance measure in case of laser material processing;, Physics Procedia
Vol. 5
, pp. 473
–481
, LANE 2010, Elsevier
11.
Hierl
, Th
. (2011
) Laser welding and heat flux thermography
, in Laser Technology Journal
, no. 3
/2011, pp. 54
–57
12.
Göttsch
, U.
(2012
) Qualitätssicherungsstrategien für Laserfügeprozesse im Karosserierohbau, EALA 2012 – European Automotive Laser Applications
, Bad Nauheim, Germany
This content is only available via PDF.
© 2012 Laser Institute of America.
2012
Laser Institute of America
You do not currently have access to this content.