Full penetration detection in Nd:YAG laser welding by analysis of oscillatory optical signals: application to overlap weld seam tracking

Duncan P. Hand; Frank M. Haran; Julian D. C. Jones; Christopher Peters

doi:10.1117/12.270125

4 April 1997 Full penetration detection in Nd:YAG laser welding by analysis of oscillatory optical signals: application to overlap weld-seam tracking

Duncan P. Hand, Frank M. Haran, Julian D. C. Jones, Christopher Peters

Author Affiliations +

Proceedings Volume 3092, XI International Symposium on Gas Flow and Chemical Lasers and High-Power Laser Conference; (1997) https://doi.org/10.1117/12.270125
Event: XI International Symposium on Gas Flow and Chemical Lasers and High Power Laser Conference, 1996, Edinburgh, United Kingdom

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.

Citation Download Citation

Duncan P. Hand, Frank M. Haran, Julian D. C. Jones, and Christopher Peters "Full penetration detection in Nd:YAG laser welding by analysis of oscillatory optical signals: application to overlap weld-seam tracking", Proc. SPIE 3092, XI International Symposium on Gas Flow and Chemical Lasers and High-Power Laser Conference, (4 April 1997); https://doi.org/10.1117/12.270125

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