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Proceedings Paper

Full penetration detection in Nd:YAG laser welding by analysis of oscillatory optical signals: application to overlap weld seam tracking
Author(s): Duncan P. Hand; Frank M. Haran; Julian D. C. Jones; Christopher Peters
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Paper Abstract

We describe a non-intrusive optical sensor for process monitoring of Nd:YAG laser welding, using light returned through the core of the power delivery optical fiber. This sensor is referred to as the core power monitor (core PM), and uses the delivery fiber to collect the broadband light generated in the process, which is then divided into spectral bands (designated as UV/visible and IR). These optical signals exhibit a characteristic oscillatory intensity modulation within the frequency range 2 - 5 kHz, which is believed to arise from a combination of keyhole, and weld pool oscillations. The frequency content may be related to the size and shape of the welding keyhole, and an alarm system for overlap weeding has been developed based on this principle. This can detect both misalignment of the focused laser spot off the seam, and any excessive gap between the plates.

Paper Details

Date Published: 4 April 1997
PDF: 4 pages
Proc. SPIE 3092, XI International Symposium on Gas Flow and Chemical Lasers and High-Power Laser Conference, (4 April 1997); doi: 10.1117/12.270125
Show Author Affiliations
Duncan P. Hand, Heriot-Watt Univ. (United Kingdom)
Frank M. Haran, Heriot-Watt Univ. (United Kingdom)
Julian D. C. Jones, Heriot-Watt Univ. (United Kingdom)
Christopher Peters, Lumonics Ltd. (United Kingdom)

Published in SPIE Proceedings Vol. 3092:
XI International Symposium on Gas Flow and Chemical Lasers and High-Power Laser Conference
Denis R. Hall; Howard J. Baker, Editor(s)

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