A Seam Measurement Method Based on Micro Depth of Field for Laser Welding

Abstract:

For the seam feature measurement of the tight butt joint without misalignment in laser welding, current vision sensor cannot obtain the seam gap width and seam position stably and reliably. In this paper, a seam measurement method based on the micro depth of field is proposed. A four times optical magnification lens, a CCD/CMOS camera and an external LED lighting unit are used to constitute the measure system, which can be used for the tight butt joint for laser welding. Experiment indicated that it can obtain the seam gap width and seam position stably and correctly. With the method, seam surface normal vector also can be measured. The measurement accuracy for the seam gap width and seam position is 5 µm and 6 µm, respectively. Furthermore, the narrowest welding seam gap that can be measured by this method is 0.02 mm, which is fully satisfied the demand of the seam measurement in laser welding.

• Periodical: Applied Mechanics and Materials (Volumes 121-126)
• Pages: 3107-3112
• DOI: https://doi.org/10.4028/www.scientific.net/AMM.121-126.3107
• Online since: October 2011
• Authors: Ping Jiang Wang, Ya Ting Huang, Fang Yu Peng, Jiang Fei Qi, Bin Li
• Keywords: Butt Joint, Definition, Laser Welding, Micro Depth of Field, Vision Sensor

References

[1] J.Y. Wu, P.J. Wang and X.D. Fu: IEEE International Conference on Mechatronics and Automation (Changchun, China, August 9-12, 2009). Vol. 1-7, pp.2548-2553.

[2] J.Y. Wu, P.J. Wang and J.H. Chen: Transactions of the China Welding Vol. 30 (2009), pp.105-108, in Chinese.

[3] J.W. Kim and J.H. Shin: Proceedings of the Institution of Mechanical Engineers, Part B: Journal of Engineering Manufacture Vol. 217 (2003), pp.1305-1313.

[4] S.S. Zeng, Y.H. Shi and G.R. Wang: Welding Technology Vol. 37 (2008), pp.1-5, in Chinese.

[5] K.Y. Bae, T.H. Lee and K.C. Ahn: Journal of Materials Processing Technology Vol. 120 (2002), pp.458-465.

[6] H.Y. Shen, H.B. Ma and T. Lin: Industrial Robot-An International Journal Vol. 34 (2007), pp.467-475.

[7] H.J. Lan: Journal of Liuzhou Teachers College Vol. 16 (2001), pp.67-69, in Chinese.

[8] P.J. Wang, D.J. Chen and M.L. Wu: China Mechanical Engineering Vol. 18 (2007), pp.2555-2560, in Chinese.

[9] J.Y. Yu and S.J. Na: Mechatronics Vol. 7 (1997), pp.599-612.

[10] S.B. Chen, X.Z. Chen and T. Qiu: Journal of Intelligent and Robotic Systems Vol. 43 (2005), pp.77-97.

[11] H.Y. Shen, T. Lin and S.B. Chen: Journal of Intelligent and Robotic Systems Vol. 59 (2010), pp.283-298.

[12] S.K. Lee, S.J. Na: Journal of Manufacturing Systems Vol. 21 (2002), p.302–315.