OSA's Digital Library

Applied Optics

Applied Optics


  • Vol. 40, Iss. 33 — Nov. 20, 2001
  • pp: 6019–6025

Optical sensor for real-time monitoring of CO2 laser welding process

Antonio Ancona, Vincenzo Spagnolo, Pietro Mario Lugarà, and Michele Ferrara  »View Author Affiliations

Applied Optics, Vol. 40, Issue 33, pp. 6019-6025 (2001)

View Full Text Article

Enhanced HTML    Acrobat PDF (715 KB)

Browse Journals / Lookup Meetings

Browse by Journal and Year


Lookup Conference Papers

Close Browse Journals / Lookup Meetings

Article Tools



An optical sensor for real-time monitoring of laser welding based on a spectroscopic study of the optical emission of plasma plumes has been developed. The welding plasma’s electron temperature was contemporarily monitored for three of the chemical species that constitute the plasma plume by use of related emission lines. The evolution of electron temperature was recorded and analyzed during several welding procedures carried out under various operating conditions. A clear correlation between the mean value and the standard deviation of the plasma’s electron temperature and the quality of the welded joint has been found. We used this information to find optimal welding parameters and for real-time detection of weld defects such as crater formation, lack of penetration, weld disruptions, and seam oxidation.

© 2001 Optical Society of America

OCIS Codes
(120.4820) Instrumentation, measurement, and metrology : Optical systems
(120.6200) Instrumentation, measurement, and metrology : Spectrometers and spectroscopic instrumentation
(120.6780) Instrumentation, measurement, and metrology : Temperature
(140.3390) Lasers and laser optics : Laser materials processing
(350.5400) Other areas of optics : Plasmas

Original Manuscript: April 10, 2001
Revised Manuscript: August 6, 2001
Published: November 20, 2001

Antonio Ancona, Vincenzo Spagnolo, Pietro Mario Lugarà, and Michele Ferrara, "Optical sensor for real-time monitoring of CO2 laser welding process," Appl. Opt. 40, 6019-6025 (2001)

Sort:  Author  |  Year  |  Journal  |  Reset  


  1. D. A. Stone, J. S. Smith, J. Lucas, “Sensor for automated weld bead penetration control,” Meas. Sci. Technol. 1, 1143–1143 (1990). [CrossRef]
  2. D. A. Stone, J. S. Smith, J. Lucas, “Sensor for automated front face weldbead area control,” Meas. Sci. Technol. 3, 263–269 (1991). [CrossRef]
  3. D. A. Stone, J. S. Smith, J. Lucas, “Sensor for automated frontface weldbead area control,” Meas. Sci. Technol. 5, 93–99 (1994). [CrossRef]
  4. A. Bicknell, J. S. Smith, J. Lucas, “Infrared sensor for top face monitoring of weld pools,” Meas. Sci. Technol. 5, 371–378 (1994). [CrossRef]
  5. L. Li, D. J. Brookfield, W. M. Steen, “Plasma charge sensor for in-process, non-contact monitoring of the laser welding process,” Meas. Sci. Technol. 7, 615–626 (1996). [CrossRef]
  6. H. Gu, W. W. Duley, “A statistical approach to acoustic monitoring of laser welding,” J. Phys. D 29, 556–561 (1996). [CrossRef]
  7. D. P. Hand, C. Peters, J. D. C. Jones, “Nd:YAG laser welding process monitoring by non-intrusive optical detection in the fibre optic delivery system,” Meas. Sci. Technol. 6, 1389–1389 (1995). [CrossRef]
  8. P. Sforza, D. de Blasiis, V. Lombardo, V. Santacesaria, M. Dell’Erba, “A three-modules sensor for CO2 laser welding and cutting processes,” in Projection Displays, M. H. Wu, ed., Proc. SPIE.2407, 116–126 (1994).
  9. J. Beersiek, R. Proprawe, W. Schulz, H. Gu, R. E. Muller, W. W. Duley, “On-line monitoring of penetration depth in laser beam welding,” in Laser Materials Processing’s, Proceedings of the 18th International Congress on Applications of Lasers and Electro-Optics, 15–18 November, 1999, San Diego, Calif., P. Christiansen, P. Denney, I. Miyamoto, K. Watkins, eds. (Laser Institute of America, Orlando, Fla., 1999), sect. D, pp. 49–58.
  10. S. Biermann, A. Topkaya, M. Jagiella, “Capacitive clearence sensor system for high quality Nd:YAG laser cutting and welding of sheet metal,” in Proceedings of the 4th European Conference on Laser Treatment of Materials, 12–15 October 1992, Gottingen, Germany, B. L. Mordike, ed. (DGM-Informationsgesellschaft Verlag, Oberursel, Germany, 1992), sect. 110, pp. 51–55.
  11. F. M. Haran, D. P. Hand, C. Peters, J. D. C. Jones, “Focus control system for laser welding,” Appl. Opt. 36, 5246–5251 (1997). [CrossRef] [PubMed]
  12. Jurca Optoelektronik GmbH, model LWM900.
  13. J. Dowden, P. Kapadia, N. Postacioglu, “An analysis of the laser–plasma interaction in laser keyhole welding,” J. Phys. D 22, 741–749 (1989). [CrossRef]
  14. B. R. Finke, P. D. Kapadia, J. R. Dowden, “A fundamental plasma based model for energy transfer in laser material processing,” J. Phys. D 23, 643–655 (1990). [CrossRef]
  15. U. Dilthey, A. Goumeniouk, V. Lopota, G. Turichin, “Kinetic description of keyhole plasma in laser welding,” J. Phys. D 33, 2747–2753 (2000). [CrossRef]
  16. W. Sokolowski, G. Herziger, E. Beyer, “Spectral plasma diagnostics in welding with CO2 lasers,” in High-power CO2 Laser Systems and Applications, A. Quenzer, ed., Proc. SPIE1020, 96–102 (1998). [CrossRef]
  17. W. Sokolowski, G. Herziger, E. Beyer, “Spectroscopic study of laser induced plasma in the welding process of steel and aluminum,” in Glasses for Optoelectronics, G. C. Righini, ed., Proc. SPIE1128, 328–335 (1989).
  18. T. J. Rockstroh, J. Mazumder, “Spectroscopic studies of plasma during cw laser materials interaction,” J. Appl. Phys. 61, 917–923 (1987). [CrossRef]
  19. J. T. Knudtson, W. B. Green, D. G. Sutton, “The UV–visible spectroscopy of laser-produced aluminum plasmas,” J. Appl. Phys. 61, 4771–4780 (1987). [CrossRef]
  20. A. Poueyo-Verwaerde, R. Fabbro, G. Deshors, D. Frutos, P. Orza, “Experimental study of laser induced plasma in welding conditions with continuous CO2 laser,” J. Appl. Phys. 74, 5773–5780 (1993). [CrossRef]
  21. Z. Szymanski, J. Kurzyna, “Spectroscopic measurement of laser induced plasma during welding with CO2 laser,” J. Appl. Phys. 76, 7750–7756 (1994). [CrossRef]
  22. D. Lacroix, G. Jeandel, C. Boudot, “Spectroscopic characterization of laser-induced plasma created during welding with a pulsed Nd:YAG laser,” J. Appl. Phys. 81, 6599–6606 (1997). [CrossRef]
  23. Z. Szymanski, J. Kurzyna, W. Kalita, “The spectroscopy of the plasma plume induced during laser welding of stainless steel and titanium,” J. Phys. D 30, 3153–3162 (1997). [CrossRef]
  24. J. Mazumder, T. J. Rockstroh, H. Krier, “Spectroscopic studies of plasma during cw laser gas heating in flowing argon,” J. Appl. Phys. 62, 4712–4718 (1987). [CrossRef]
  25. H. R. Griem, Plasma Spectroscopy (McGraw-Hill, New York, 1964), Chap. 14.
  26. R. Miller, T. DebRoy, “Energy absorption by metal-vapor-dominated plasma during carbon dioxide laser welding of steels,” J. Appl. Phys. 68, 2045–2050 (1990). [CrossRef]
  27. M. Ferrara, A. Ancona, P. M. Lugarà, M. Sibilano, “On-line quality monitoring of welding processes by means of plasma optical spectroscopy,” in High-Power Lasers in Manufacturing, X. Chen, T. Fujiioka, A. Matsunawa, eds., Proc. SPIE3888, 750–758 (2000). [CrossRef]

Cited By

Alert me when this paper is cited

OSA is able to provide readers links to articles that cite this paper by participating in CrossRef's Cited-By Linking service. CrossRef includes content from more than 3000 publishers and societies. In addition to listing OSA journal articles that cite this paper, citing articles from other participating publishers will also be listed.

« Previous Article  |  Next Article »

OSA is a member of CrossRef.

CrossCheck Deposited