Effect of Nozzle Shape on Micro-Cutting Performance of Thin Metal Sheet by Pulsed Nd:  YAG Laser

Yasuhiro Okamoto; Yoshiyuki Uno; Hiroshi Suzuki

doi:10.20965/ijat.2010.p0510

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IJAT Vol.4 No.6 pp. 510-517

doi: 10.20965/ijat.2010.p0510

(2010)

Paper:

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Effect of Nozzle Shape on Micro-Cutting Performance of Thin Metal Sheet by Pulsed Nd: YAG Laser

Yasuhiro Okamoto, Yoshiyuki Uno, and Hiroshi Suzuki

Graduate School of Natural Science and Technology, Okayama University, 3-1-1 Tsushimanaka, Kita-ku, Okayama 700-8530, Japan

Received:

May 28, 2010

Accepted:

July 30, 2010

Published:

November 5, 2010

Keywords:

nozzle shape, Laval throat, fine cutting, dross, Nd: YAG laser

Abstract

In precision laser cutting, the generation of dross can be reduced by using a high-pressure assist gas flow. However, our previous work made it clear that, for a conventional convergent nozzle, the pressure of assist gas on a workpiece is reduced to less than half of the cylinder gas pressure because of the generation of Mach Shock Disk. Furthermore, the removal of material from the micro-kerf becomes difficult since the fluidity of molten material is low in the narrow kerf. Therefore, nozzle shapes were investigated to improve the removal of material from the micro-kerf, and their effect on the fine cutting of a thin metal plate using a pulsed Nd: YAG laser was also discussed. The height of dross could be reduced by using a Laval throat nozzle with an initial expansion zone compared with that for a straight throat nozzle. The pressure on the workpiece was greater, and the straightness of the assist gas flow was excellent when the Laval throat nozzle with the initial expansion zone was used. Moreover, it was confirmed that the molten material could be effectively removed from the micro-kerf even at a middle cylinder gas pressure of around 600 kPa. Therefore, the Laval throat nozzle with the initial expansion zone can be used for fine cutting owing to its reduction of dross.

Cite this article as:

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. Automation Technol., Vol.4 No.6, pp. 510-517, 2010.

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References

[1] W. M. Steen, “Laser Material Processing,” Springer-Verlag, p. 133, 2003.
[2] G. Chryssolouris, “Laser Machining Theory and Practice,” Springer-Verlag, p. 220, 1991.
[3] J. M. Dowden, “The Theory of Laser Materials Processing,” Springer Science + Business Media B. V., p. 62, 2009.
[4] Y. Uno, Y. Okamoto, K. Hirose, S. Kawaguchi, S. Kubota, and N. Miyanagi, “Study on Supplying Method of Assist Gas in Precision Cutting with Pulsed YAG Laser,” J. of the Japan Society for Precision Engineering, 65-10, pp. 1471-1475, 1999 (in Japanese).
[5] Y. Okamoto, Y. Uno, and N. Miyanagi, “Effect of Nozzle Shape on Surface Integrity in Micro Cutting with Pulsed YAG Laser,” Proc. of 1st Int. Symp. on Laser Precision Microfabrication, Ohmiya, pp. 291-294, 2000.
[6] 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, 70-2, pp. 87-91, 2004(in Japanese).
[7] 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.
[8] Y. Uno and Y. Okamoto: Japanese patent 3789899.
[9] M. Boutinguiza, J. Pou, F. Lusquiñosa, F. Quinteroa, R. Sotoa, M. Pérez-Amora, K. Watkinsb, and W. M. Steen, “CO₂ laser cutting of slate”, Optics and Lasers in Engineering,” 37, pp. 15-25, 2002.
[10] J. F. Ready et al., “LIA Handbook of Laser Material Processing,” Laser Institute of America, Magnolia Publishing, Inc., ISBN 0-912035-15-3, p. 158, 2001.

This article is published under a Creative Commons Attribution-NoDerivatives 4.0 Internationa License.

[1] [1] W. M. Steen, “Laser Material Processing,” Springer-Verlag, p. 133, 2003.

[2] [2] G. Chryssolouris, “Laser Machining Theory and Practice,” Springer-Verlag, p. 220, 1991.

[3] [3] J. M. Dowden, “The Theory of Laser Materials Processing,” Springer Science + Business Media B. V., p. 62, 2009.

[4] [4] Y. Uno, Y. Okamoto, K. Hirose, S. Kawaguchi, S. Kubota, and N. Miyanagi, “Study on Supplying Method of Assist Gas in Precision Cutting with Pulsed YAG Laser,” J. of the Japan Society for Precision Engineering, 65-10, pp. 1471-1475, 1999 (in Japanese).

[5] [5] Y. Okamoto, Y. Uno, and N. Miyanagi, “Effect of Nozzle Shape on Surface Integrity in Micro Cutting with Pulsed YAG Laser,” Proc. of 1st Int. Symp. on Laser Precision Microfabrication, Ohmiya, pp. 291-294, 2000.

[6] [6] 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, 70-2, pp. 87-91, 2004(in Japanese).

[7] [7] 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.

[8] [8] Y. Uno and Y. Okamoto: Japanese patent 3789899.

[9] [9] M. Boutinguiza, J. Pou, F. Lusquiñosa, F. Quinteroa, R. Sotoa, M. Pérez-Amora, K. Watkinsb, and W. M. Steen, “CO₂ laser cutting of slate”, Optics and Lasers in Engineering,” 37, pp. 15-25, 2002.

[10] [10] J. F. Ready et al., “LIA Handbook of Laser Material Processing,” Laser Institute of America, Magnolia Publishing, Inc., ISBN 0-912035-15-3, p. 158, 2001.