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IJAT Vol.10 No.6 pp. 874-881
doi: 10.20965/ijat.2016.p0874
(2016)

Paper:

Characteristics of Spatter in Micro-Drilling of Metal Sheet by Pulsed Nd:YAG Laser

Yasuhiro Okamoto, Hibiki Yamamoto, and Akira Okada

Okayama University
3-1-1 Tsushimanaka, Kita-ku, 700-8530 Okayama, Japan

Corresponding author,

Received:
May 14, 2016
Accepted:
August 3, 2016
Published:
November 4, 2016
Keywords:
laser processing, spatter, velocity, angle, micro-drilling, high-speed observation, CFD
Abstract
In laser cutting and drilling process, molten material was scattered as spatter, which deteriorates the surface integrity of a workpiece because of the thermal damage. It is expected that the control of assist gas flow can reduce the adhesion of spatter. In order to investigate the improvement method of thermal damage due to the adhesion of spatter, it is required to clarify characteristics of spatter. Therefore, a method was developed to collect and analyze spatter based on the use of high-speed video cameras in the laser micro-drilling process, and the characteristics of spatter movement were numerically investigated by CFD analysis. The scattering velocity and angle of the spatter were investigated by recognizing and tracking spatter with the high-speed video observation. The movement of spatter was observed by using two high-speed video cameras, and analyzed by using a two-direction tracking method, in which the 3D tracking lines of spatter particles were reconstructed in the forward and backward frames, and the actual trajectory of individual spatter particle was obtained by averaging those tracking lines. These measurements revealed that the initial velocity of spatter was mainly distributed from 52 m/s to 200 m/s with an average velocity of 129 m/s. The initial angle of spatter was mainly distributed between 0 and 30 degrees from the workpiece surface in the upward direction. There was little correlation between the initial velocity and angle of spatter. The diameter of spatter was mainly distributed from 1 μm to 4 μm with an average diameter of 3.7 μm. It is important to use the processing conditions achieving the smaller spatter diameter in order to reduce the thermal damage caused by spatter. Although coaxial assist gas flow has an influence on the spatter behavior, that time period is very short. Therefore, it is important to control the spatter behavior outside of the coaxial assist gas flow by using an additional gas flow to prevent the thermal damage to the workpiece surface.
Cite this article as:
Y. Okamoto, H. Yamamoto, and A. Okada, “Characteristics of Spatter in Micro-Drilling of Metal Sheet by Pulsed Nd:YAG Laser,” Int. J. Automation Technol., Vol.10 No.6, pp. 874-881, 2016.
Data files:
References
  1. [1] J. F. Ready et al., “LIA Handbook of Laser Material Processing,” Laser Institute of America, Magnolia Publishing, Inc., ISBN 0-912035-15-3, 2001.
  2. [2] M. Boutinguiza, J. Pou, F. Lusqui nosa, F. Quinteroa, R. Sotoa, M. P’erez-Amora, K. Watkinsb, and W. M. Steen, “CO2 laser cutting of slate,” Optics and Lasers in Engineering, Vol.37, pp. 15-25, 2002.
  3. [3] Y. Okamoto, Y. Uno, M. Hosogaya, and N. Miyanagi, “Precision Micro Cutting of Thin Steel Plate with Newly Designed Laval Nozzle by Pulsed YAG Laser,” Proc. of 23rd Int. Congress on Applications of Lasers & Electro-Optics, Precision Drilling & Cutting, pp. 20-27, 2004.
  4. [4] Y. Okamoto, Y. Uno, Y. Murakami, M. Hosogaya, and N. Miyanagi, “Effects of Nozzle Shape on Precision Micro Cutting of Thin Metal Plate by Pulsed YAG Laser,” J. of the Japan Society for Precision Engineering, Vol.70, No.2, pp. 87–91, 2004.
  5. [5] Y. Okamoto, Y. Uno, and H. Suzuki, “Effect of nozzle shape on micro-cutting performance of thin metal sheet by pulsed Nd:YAG laser,” Int. J. of Automation Technology, Vol.4, No.6, pp. 510–517, 2010.
  6. [6] A. F. H. Kaplana and J. Powell, “Spatter in laser welding,” J. of Laser Applications, Vol.23, No.3, pp. 032005-1–03205-7, 2011.
  7. [7] M. Schweier, J. F. Heins, M. W. Haubold, and M. F. Zaeh, “Spatter Formation in Laser Welding with Beam Oscillation,” Physics Procedia, Vol.41, pp. 20-30, 2013.
  8. [8] J.-K. Kim, H.-S. Lim, J.-H. Cho, and C.-H. Kim, “Bead-on-plate Weldability of Al 5052 Alloy Using a Disk Laser,” J. of Achievements in Materials and Manufacturing Engineering, Vol.28 Issue 2, 2008.
  9. [9] X. Gao, Y. Sun, and S. Katayama, “Neural Network of Plume and Spatter for Monitoring High-power Disk Laser Welding,” Int. J. of Precision Engineering and Manufacturing-Green Technology, Vol.1, No.4, pp. 293-298, 2014.
  10. [10] T. Viitanen, J. Kolehmainen, R. Piché, and Y. Okamoto, “Spatter Tracking in Laser Machining,” Advances in Visual Computing (8th International Symposium, ISVC 2012, Rethymnon, Crete, Greece, July 16-18, 2012, Revised Selected Papers, Part II), Lecture Notes in Computer Science, Vol.7432, pp. 626-635, 2012.
  11. [11] Y. Okamoto, H. Yamamoto, A. Okada, K. Shirasaya, and J. T. Kolehmainen, “Velocity and Angle of Spatter in Fine Laser Processing,” Physics Procedia, Vol.39, pp.792-799, 2012.
  12. [12] D. G. Lowe, “Object recoqnition from local scale-invariant features,” The proc. of the Seventh IEEE International Conference on Computer Vision., pp. 1150-1157, 1999.
  13. [13] A. Doucet, S. God sill, and C. Andrieu, “On sequential Monte Carlo smapling methods for Bayesian filtering,” Statistics and Computing, Vol.10, No.3, pp. 197-208, 2000.
  14. [14] Z. Zhang, “A flexible new technique for camera caliblation,” IEEE Trans. on Pattern Analysis and Machine Intelligence, Vol.22, No.11, pp. 1330-1334, 2000.
  15. [15] Q. T. Luong and O. D. Faugeras, “The fundamental matrix: theory, algorithms, and stability analysis,” Int. J. of Computer Vision, Vol.17, No.1, pp. 43-75, 1996.
  16. [16] S. J. Julier, and J. K. Uhlmann, “A new extension of the Kalman filter to nonlinear systems,” Int. Symposium Aerospace / Defense Sensing, Simulation and Controls, Vol.3, pp. 182-193, 1997.
  17. [17] W. Hastings, “Monte Carlo sampling methods using Markov chains and their applications,” Biometrika, No.57, pp. 97-109, 1970.
  18. [18] G. Chryssolouris, “Laser Machining Theory and Practice,” Springer-Verlag, 1991.
  19. [19] I. Ito and M. Honda, “Fluid mechanics, Maruzen,” 1981.
  20. [20] K. Matsuo, “Compressible Fluid Mechanics,” Rikogakusha Publishing, 1994.

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