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Optics Express

Optics Express

  • Editor: Andrew M. Weiner
  • Vol. 21, Iss. 17 — Aug. 26, 2013
  • pp: 19997–20004

Direct observation of keyhole characteristics in deep penetration laser welding with a 10 kW fiber laser

Mingjun Zhang, Genyu Chen, Yu Zhou, and Shichun Li  »View Author Affiliations

Optics Express, Vol. 21, Issue 17, pp. 19997-20004 (2013)

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Keyhole formation is a prerequisite for deep penetration laser welding. Understanding of the keyhole dynamics is essential to improve the stability of the keyhole. Direct observation of the keyhole during deep penetration laser welding of a modified “sandwich” specimen with a 10 kW fiber laser is presented. A distinct keyhole wall and liquid motion along the wall are observed directly for the first time. The moving liquid “shelf” on the front keyhole wall and the accompanying hydrodynamic and vapor phenomena are observed simultaneously. Micro-droplets torn off the keyhole wall and the resultant bursts of vapor are also visualized. The hydrodynamics on the keyhole wall has a dominant effect on the weld defects. The emission spectrum inside the keyhole is captured accurately using a spectrometer to calculate the characteristics of the keyhole plasma plume.

© 2013 OSA

OCIS Codes
(140.0140) Lasers and laser optics : Lasers and laser optics
(140.3390) Lasers and laser optics : Laser materials processing
(300.6170) Spectroscopy : Spectra
(300.6360) Spectroscopy : Spectroscopy, laser
(150.0155) Machine vision : Machine vision optics
(150.5495) Machine vision : Process monitoring and control

ToC Category:
Lasers and Laser Optics

Original Manuscript: April 3, 2013
Revised Manuscript: July 27, 2013
Manuscript Accepted: August 1, 2013
Published: August 16, 2013

Mingjun Zhang, Genyu Chen, Yu Zhou, and Shichun Li, "Direct observation of keyhole characteristics in deep penetration laser welding with a 10 kW fiber laser," Opt. Express 21, 19997-20004 (2013)

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  1. S. Katayama, Y. Kawahito, and M. Mizutani, “Latest Progress in Performance and Understanding of Laser Welding,” Phys. Procedia39, 8–16 (2012). [CrossRef]
  2. Y. Qin, A. Michalowski, R. Weber, S. Yang, T. Graf, and X. Ni, “Comparison between ray-tracing and physical optics for the computation of light absorption in capillaries--the influence of diffraction and interference,” Opt. Express20(24), 26606–26617 (2012). [CrossRef] [PubMed]
  3. M. Kraus, M. A. Ahmed, A. Michalowski, A. Voss, R. Weber, and T. Graf, “Microdrilling in steel using ultrashort pulsed laser beams with radial and azimuthal polarization,” Opt. Express18(21), 22305–22313 (2010). [CrossRef] [PubMed]
  4. A. F. Kaplan, “Fresnel absorption of 1μm-and 10μm-laser beams at the keyhole wall during laser beam welding: Comparison between smooth and wavy surfaces,” Appl. Surf. Sci.258(8), 3354–3363 (2012). [CrossRef]
  5. A. F. Kaplan, “Local absorptivity modulation of a 1μm-laser beam through surface waviness,” Appl. Surf. Sci.258(24), 9732–9736 (2012). [CrossRef]
  6. Optics.org news “IPG set to ship 100 kW laser” (Optics.org, 2012), http://optics.org/news/3/10/44 .
  7. P. Haug, V. Rominger, N. Speker, R. Weber, T. Graf, M. Weigl, and M. Schmidt, “Influence of laser wavelength on melt bath dynamics and resulting seam quality at welding of thick plates,” Phys. Procedia41, 49–58 (2013). [CrossRef]
  8. Y. Kawahito, M. Mizutani, and S. Katayama, “High quality welding of stainless steel with 10 kW high power fibre laser,” Sci. Technol. Weld. Join.14(4), 288–294 (2009). [CrossRef]
  9. T. Ilar, I. Eriksson, J. Powell, and A. Kaplan, “Root humping in laser welding–an investigation based on high speed imaging,” Phys. Procedia39, 27–32 (2012). [CrossRef]
  10. A. Matsunawa, J. D. Kim, N. Seto, M. Mizutani, and S. Katayama, “Dynamics of keyhole and molten pool in laser welding,” J. Laser Appl.10(6), 247–254 (1998). [CrossRef]
  11. R. Fabbro, S. Slimani, I. Doudet, F. Coste, and F. Briand, “Experimental study of the dynamical coupling between the induced vapour plume and the melt pool for Nd-Yag CW laser welding,” J. Phys. D Appl. Phys.39(2), 394–400 (2006). [CrossRef]
  12. Y. Arata, H. Maruo, I. Miyamoto, and S. Takeuchi,R. A. Bakish, ed., “Dynamic Behavior of Laser Welding and Cutting,” in Proceedings 7th International Conference on Electron and Ion Beam Science and Technology, R. A. Bakish, ed. (Washington, D.C., 1976), pp. 111–128.
  13. Y. Arata, N. Abe, and T. Oda, “Fundamental phenomena in high power CO2 laser welding,” Trans. JWRI14(1), 5–11 (1985).
  14. N. Seto, S. Katayama, and A. Matsunawa, “High-speed simultaneous observation of plasma and keyhole behavior during high power CO2 laser welding: effect of shielding gas on porosity formation,” J. Laser Appl.12(6), 245–250 (2000). [CrossRef]
  15. Y. Kawahito, M. Mizutani, and S. Katayama, “Elucidation of high-power fibre laser welding phenomena of stainless steel and effect of factors on weld geometry,” J. Phys. D Appl. Phys.40(19), 5854–5859 (2007). [CrossRef]
  16. P. Berger, H. Hügel, and T. Graf, “Understanding Pore Formation in Laser Beam Welding,” Phys. Procedia12, 241–247 (2011). [CrossRef]
  17. X. Jin, P. Berger, and T. Graf, “Multiple reflections and Fresnel absorption in an actual 3D keyhole during deep penetration laser welding,” J. Phys. D Appl. Phys.39(21), 4703–4712 (2006). [CrossRef]
  18. Y. Zhang, L. Li, and G. Zhang, “Spectroscopic measurements of plasma inside the keyhole in deep penetration laser welding,” J. Phys. D Appl. Phys.38(5), 703–710 (2005). [CrossRef]
  19. Y. Zhang, G. Chen, H. Wei, and J. Zhang, “A novel 'sandwich' method for observation of the keyhole in deep penetration laser welding,” Opt. Lasers Eng.46(2), 133–139 (2008). [CrossRef]
  20. X. Jin, L. Zeng, and Y. Cheng, “Direct observation of keyhole plasma characteristics in deep penetration laser welding of aluminum alloy 6016,” J. Phys. D Appl. Phys.45(24), 245205 (2012). [CrossRef]
  21. V. S. Golubev, “On possible models of hydrodynamical nostationary phenomena in processes of laser beam deep penetration into materials,” Proc. SPIE2713, 219–230 (1995). [CrossRef]
  22. A. A. Samokhin, “Influence of evaporation on metallic melt behaviour under laser action,” Kvantovaya Elektronika10, 2022–2026 (1983).
  23. V. S. Golubev, “Laser welding and cutting: recent insights into fluid dynamics mechanisms,” Proc. SPIE5121, 1–15 (2003). [CrossRef]
  24. V. S. Golubev, “Possible hydrodynamic phenomena in deep-penetration laser channels,” Proc. SPIE3888, 244–253 (2000). [CrossRef]
  25. A. Matsunawa, N. Seto, J. D. Kim, M. Mizutani, and S. Katayama, “Dynamics of keyhole and molten pool in high power CO2 laser welding,” Proc. SPIE3888, 34–45 (2000). [CrossRef]
  26. S. Pang, L. Chen, J. Zhou, Y. Yin, and T. Chen, “A three-dimensional sharp interface model for self-consistent keyhole and weld pool dynamics in deep penetration laser welding,” J. Phys. D Appl. Phys.44(2), 025301 (2011). [CrossRef]
  27. A. Matsunawa and V. Semak, “The simulation of front keyhole wall dynamics during laser welding,” J. Phys. D Appl. Phys.30(5), 798–809 (1997). [CrossRef]
  28. I. Eriksson, J. Powell, and A. F. H. Kaplan, “Measurements of fluid flow on keyhole front during laser welding,” Sci. Technol. Weld. Join.16(7), 636–641 (2011). [CrossRef]
  29. J. Dowden, P. Kapadia, A. Clucas, R. Ducharme, and W. M. Steen, “On the relation between fluid dynamic pressure and the formation of pores in laser keyhole welding,” J. Laser Appl.8(4), 183–190 (1996). [CrossRef]
  30. C. Aragón and J. A. Aguilera, “Characterization of laser induced plasmas by optical emission spectroscopy: A review of experiments and methods,” Spectrochim. Acta B63(9), 893–916 (2008). [CrossRef]
  31. J. M. Dowden, P. Kapadia, and N. Postacioglu, “An analysis of the laser-plasma interaction in laser keyhole welding,” J. Phys. D Appl. Phys.22(6), 741–749 (1989). [CrossRef]

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