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Keyhole stability during laser welding—part I: modeling and evaluation

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Abstract

The keyhole is a requirement in order to establish the energy efficient process of laser deep penetration welding. However, the process is highly unstable which results in unwanted pore and spatter formation. In order to avoid process defects, the physical effects in the keyhole have to be better understood to find ways for compensation. This work aims to describe the keyhole properties at different welding parameters for welding of aluminum (EN AW 1050) with the help of a semi-analytical model based on energy and pressure equations and differential equations. The resulting dynamic characteristics of different keyholes are evaluated with frequency analysis of optical observations during the welding process. The spring coefficient, that describes the radial pressure change at radius deviation, is a good indicator for the resulting keyhole dynamics. Dynamic behavior is influenced by the spatial laser intensity distribution, while higher frequencies at lower amplitudes are found at a Top Hat distribution compared to a Gaussian intensity profile.

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References

  1. Hügel H, Graf T (2009) Laser in der Fertigung: Strahlquellen, Systeme, Fertigungsverfahren. Vieweg+Teubner, Stuttgart

    Book  Google Scholar 

  2. Duley WW (1976) CO2 lasers: effects and applications. Academic, London, p 246

    Google Scholar 

  3. Mizutani M, Katayama S (2003) Keyhole behavior and pressure distribution during laser irradiation on molten metal. In: Proceedings of the 22nd international congress on applications of lasers and electro-optics, Jacksonville

  4. Zhang MJ, Chen GY, Zhou Y, Li SC, Deng H (2013) Observation of spatter formation mechanisms in high-power fiber laser welding of thick plate. Appl Surf Sci 280:868–875

    Article  Google Scholar 

  5. Khan M, Romoli L, Dini G, Fiaschi M (2011) A simplified energy-based model for laser welding of ferritic stainless steels in overlap configurations. CIRP Ann Manuf Technol 60:215–218

    Article  Google Scholar 

  6. Schmidt M, Otto A, Kägeler C, Geiger M (2008) Analysis of YAG Laser lap-welding of zinc coated steel sheets. CIRP Ann Manuf Technol 57:213–216

    Article  Google Scholar 

  7. Matsunawa A, Kim JD, Katayama S, Semak V (1996) Experimental and theoretical studies on keyhole dynamics in laser welding. In: Proceedings of the 15th international congress on application of lasers and electro-optics (ICALEO), LIA congress proceeding, vol 81, pp 58–67

  8. Otto A, Koch H, Leitz KH, Schmidt M (2011) Numerical simulations—a versatile approach for better understanding dynamics in laser material processing. In: Physics procedia, vol 12, 11–20, World of Photonics Congress, Munich, Germany

  9. Zhao H, DebRoy T (2003) Macroporosity free aluminum alloy weldments through numerical simulation of keyhole mode laser welding. J Appl Phys 93(12):10089–10096

    Article  Google Scholar 

  10. Heider A, Stritt, P, Weber R, Graf T (2015) Comparing the amount of laser welding spatters resulting from different analysing methods. In: Proceedings of the 34th international congress on applications of lasers and electro-optics (ICALEO), LIA congress proceeding, paper 607

  11. Seto N, Katayama S, Matsunawa A (2000) Porosity formation mechanism and suppression procedure in laser welding of aluminium alloys. Q J Jpn Weld Soc 18:243–255

    Article  Google Scholar 

  12. Bachmann M, Avilov V, Gumenyuk A, Rethmeier M (2013) Numerical simulation of electromagnetic melt control systems in high power laser beam welding. In: Proceedings of the 32nd international congress on application of lasers and electro-optics (ICALEO), LIA congress proceeding, paper 401

  13. Fabbro R (2009) Limiting process for keyhole propagation during deep penetration laser welding. In: Proceedings of the 5th international congress on laser advanced materials processing (LAMP)

  14. Stol I, Martukanitz RP (2004) Laser welding with beam oscillation. US patent no. 6,740,845

  15. Heider A, Stritt P, Hess A, Weber R, Graf T (2001) Process stabilization at welding copper by laser power modulation. Phys Procedia 12:81–87

    Article  Google Scholar 

  16. Li S, Chen G, Katayama S, Zhang Y (2014) Relationship between spatter formation and dynamic molten pool during high-power deep-penetration laser welding. Appl Surf Sci 303:481–488

    Article  Google Scholar 

  17. Börner C, Dilger K, Rominger V, Harrer T, Krüssel T, Löwer T (2011) Influence of ambient pressure on spattering and weld seam quality in laser beam welding with the solid-state laser. In: Proceedings of 31st international congress on applications of lasers and electro-optics (ICALEO), LIA congress proceeding, paper 1604

  18. Volpp J, Vollertsen F (2015) Modeling keyhole oscillations during laser deep penetration welding at different spatial laser intensity distributions. Prod Eng Res Dev 9(2):167–178

    Article  Google Scholar 

  19. Kägeler C, Schmidt M (2012) Frequency-based analysis of weld pool dynamics and keyhole oscillations at laser beam welding of galvanized steel sheets. Phys Procedia 39:447–453

    Article  Google Scholar 

  20. Geiger M, Kägeler C, Schmidt M (2008) High-power laser welding of contaminated steel sheets. Prod Eng 2:235–240

    Article  Google Scholar 

  21. Hoffman J, Szymanski Z, Jakubowski J, Kolasa A (2002) Analysis of acoustic and optical signals used as a basis for controlling laser-welding processes. Weld Int 16(1):18–25

    Article  Google Scholar 

  22. Klassen M (2000) Prozessdynamik und resultierende Prozessinstabilitäten beim Laserstrahlschweißen von Aluminiumlegierungen. BIAS-Verl., Bremen (in German)

    Google Scholar 

  23. Li S et al (2014) Dynamic keyhole profile during high-power deep-penetration laser welding. J Mater Process Technol 214(3):565–570

    Article  Google Scholar 

  24. Berger P, Hügel H, Graf T (2011) Understanding pore formation in laser beam welding. Phys Procedia 12:241–247

    Article  Google Scholar 

  25. Katayama S, Kawahito Y, Mizutani M (2007) Plume behaviour and melt flows during laser and hybrid welding. In: Vollertsen F, Emmelmann C, Schmidt M, Otto A (eds) Lasers in manufacturing (LIM). Elsevier, Amsterdam, pp 265–272

    Google Scholar 

  26. Fabbro R, Slimani S, Coste F, Briand F, Dlubak B, Loisel G (2006) Analysis of basic processes inside the keyhole during deep penetration Nd:YAG cw laser welding. In: Proceeding of the 25th international congress on applications of lasers and electro-optics (ICALEO) laser materials processing conference, paper 101

  27. Volpp J, Freimann D (2013) Indirect measurement of keyhole pressure oscillations during laser deep penetration welding. In: Proceedings of the 32nd international congress on applications of lasers and electro-optics (ICALEO), LIA congress proceeding, paper 1301, pp 334–340

  28. Solana P, Ocana J-L (1997) A mathematical model for penetration laser welding as a free-boundary problem. J Phys D Appl Phys 30:1300–1313

    Article  Google Scholar 

  29. Ki H, Mohanty P, Mazumder J (2002) Modeling of laser keyhole welding: Part I. Mathematical modeling, numerical methodology, role of recoil pressure, multiple reflections, and free surface evolution. Metall Mater Trans 33A:1817–1830

    Article  Google Scholar 

  30. Andrews JG, Attey DR (1976) Hydrodynamic limit to penetration of a material by a high-power beam. J Phys D Appl Phys 9:2181–2194

    Article  Google Scholar 

  31. Kroos J, Gratzke U, Simon G (1993) Towards a self-consistent model of the keyhole in penetration laser beam welding. J Phys D Appl Phys 26:474–480

    Article  Google Scholar 

  32. Klein T, Vicanek M, Simon G (1996) Forced oscillations of the keyhole in penetration laser beam welding. J Phys D Appl Phys 29:322–332

    Article  Google Scholar 

  33. Kroos J, Gratzke U, Vicanek M, Simon G (1993) Dynamic behavior of the keyhole in laser welding. J Phys D Appl Phys 26:481–486

    Article  Google Scholar 

  34. Klein T, Vicanek M, Kroos J, Decker I, Simon G (1994) Oscillations of the keyhole in penetration laser beam welding. J Phys D Appl Phys 27:2023–2030

    Article  Google Scholar 

  35. Poprawe R (2005) Lasertechnik für die Fertigung—Grundlagen, Perspektiven und Beispiele für den innovativen Ingenieur. Springer, Heidelberg

    Google Scholar 

  36. Abramowitz M, Stegun IA (1972) Handbook of mathematical functions. Dover, New York

    MATH  Google Scholar 

  37. Fabbro R, Slimani S, Coste F, Briand F (2007) Analysis of the various melt pool hydrodynamic regimes observed during cw Nd-Yag deep penetration laser welding. In: Proceedings of the 27th international congress on applications of lasers and electro-optics (ICALEO), LIA congress proceeding, paper 802

  38. Klemens PG (1976) Heat balance and flow conditions for electron beam and laser welding. J Appl Phys 47(5):2165–2174

    Article  Google Scholar 

  39. Clucas DAV, Ducharme R, Kapadia PD, Dowden JM, Steen WM (1995) A mathematical model of the flow within the keyhole during laser welding. In: Denny P, Miyamoto I, Mordike BL (eds) Proceedings of the ICALEO’95. Laser Institute of America, Orlando, pp 435–450

    Google Scholar 

  40. Matsunawa A, Semak V (1997) The simulation of front keyhole wall dynamics during laser welding. J Phys D Appl Phys 30:798–809

    Article  Google Scholar 

  41. Weberpals J-P (2010) Nutzen und Grenzen guter Fokussierbarkeit beim Laserschweißen. Dissertation, Herbert Utz Verlag GmbH, Stuttgart, University (in German)

  42. Pleteit H (2001) Analyse und Modellierung der Keyhole-Dynamik beim Laserstrahlschweißen von Aluminiumlegierungen. Dissertation Bremen, Univ. (in German)

  43. Brands EA, Brook GB (1992) Smithells metals reference book. Butterworth-Heinemann, Oxford

    Google Scholar 

  44. Geiger M, Leitz KH, Koch H, Otto A (2009) A 3D transient model of keyhole and melt pool dynamics in laser beam welding applied to the joining of zinc coated sheets. Prod Eng 3(2):127–136

    Article  Google Scholar 

  45. Gatzen M, Thomy C, Vollertsen F (2012) Analytical investigation of the influence of the spatial laser beam intensity distribution on keyhole dynamics in laser beam welding. Lasers Eng 23(1–2):109–122

    Google Scholar 

  46. MacCormack E, Mandelis A, Munidasa M, Farahbakhsh B, Sang H (1997) Measurements of thermal diffusivity of aluminum using frequency-scanned, transient, and rate window photothermal radiometry. Theory and experiment. Int J Thermophys 18(1):221–250

    Article  Google Scholar 

  47. Windisch H (2006) Thermodynamik—Ein Lehrbuch für Ingenieure. Oldenbourg Wissenschaftsverlag GmbH, München

    Google Scholar 

  48. Iida T, Guthrie RIL (1988) The physical properties of liquid metals. Clarendon Press, Oxford

    Google Scholar 

  49. Keene BJ (1993) Review of data for the surface tension of pure metals. Int Mater Rev 38(4):157–192

    Article  Google Scholar 

  50. Shcheglov P, Gumenyuk A, Gornushkin I, Rethmeier M (2011) Experimental investigation of the laser-plume interaction during high power fiber laser welding. In: Proceedings of the 31st international congress on applications of lasers and electro-optics (ICALEO), LIA congress proceeding, paper 1606

  51. Skupin J (2004) Nichtlinear dynamisches Modell zum Laserstrahlschweißen von Aluminiumlegierungen. Dissertation, Berichte aus der Lasertechnik, Shaker Verlag Aachen (in German)

  52. Boley M, Abt F, Weber R, Graf T (2013) X-ray and optical videography for 3D measurement of capillary and melt pool geometry in laser welding. Phys Procedia 41:481–488

    Article  Google Scholar 

  53. Kaplan AFH, Westin EM, Wiklund G, Norman P (2008) Imaging in cooperation with modeling of selected defect mechanisms during fiber laser welding of stainless steel. In: Proceedings of the 28th international congress on applications of lasers and electro-optics (ICALEO), LIA congress proceeding, paper 1701

  54. Kaplan AFH (2011) Influence of the beam profile formulation when modeling fiber-guided laser welding. J Laser Appl 23(4):042005

    Article  Google Scholar 

  55. Binder HH (1999) Lexikon der chemischen Elemente. S. Hirzel Verlag, Stuttgart. ISBN 3-7776-0736-3

    Google Scholar 

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Acknowledgments

This work was accomplished within the Center of Competence for Welding of Aluminum Alloys (Centr-Al). Funding by the DFG—Deutsche Forschungsgemeinschaft (VO 530/52-2) is gratefully acknowledged. The “BIAS ID” numbers are part of the figures and allow the retraceability of the results with respect to mandatory documentation required by the funding organization.

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Authors and Affiliations

  1. Bremer Institut für angewandte Strahltechnik GmbH, Klagenfurter Straße 2, 28359, Bremen, Germany

    Jörg Volpp & Frank Vollertsen

  2. University of Bremen, Bremen, Germany

    Frank Vollertsen

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  1. Jörg Volpp
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  2. Frank Vollertsen
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Correspondence to Jörg Volpp.

Appendix

Appendix

The modelled results for the Top Hat beam intensity distribution are shown in Figs. 20, 21, 22, 23, 24, 25 and 26.

Fig. 20
figure 20

Keyhole properties at different laser powers (Top Hat beam, EN AW 1050 base material, reference parameters)

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Fig. 21
figure 21

Keyhole properties at different welding velocities (Top Hat beam, EN AW 1050 base material, reference parameters)

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Fig. 22
figure 22

Keyhole properties at different focal positions (Top Hat beam, EN AW 1050 base material, reference parameters)

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Fig. 23
figure 23

Dynamic keyhole properties at different welding parameters (Top Hat beam, EN AW 1050 base material, reference parameters)

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Fig. 24
figure 24

Comparing experimentally recorded frequency spectrums and calculated frequency-amplitude-points at different laser powers (Top Hat beam)

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Fig. 25
figure 25

Comparing experimentally recorded frequency spectrums and calculated frequency-amplitude-points at different welding velocities (Top Hat beam)

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Fig. 26
figure 26

Comparing experimentally recorded frequency spectrums and calculated frequency-amplitude-points at different focal positions (Top Hat beam)

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Volpp, J., Vollertsen, F. Keyhole stability during laser welding—part I: modeling and evaluation. Prod. Eng. Res. Devel. 10, 443–457 (2016). https://doi.org/10.1007/s11740-016-0694-3

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