monitoring techniques for laser cleaning
and Lasers in Engineering 34 (2000) 429}442
Lee, K.G. Watkins Laser Group, Department of Engineering,
University of Liverpool, Brownlow Street, Liverpool
L69 3GH, UK
in-process monitoring techniques based on acoustic, chromatic
and intelligent approaches have been developed for laser
cleaning not only to achieve the sound-cleaned surface but
also to control the process in an automatic manner. The
cleaning of various materials such as copper, marble, paper
have also been carried out by using Q-switched Nd:YAG radiation.
The process was successfully monitored by detecting the
acoustic emission induced by laser}surface interactions
during laser cleaning. Novel surface monitoring was achieved
by chromatic modulation technique. The monitoring of laser
#uence based on neural network logic was carried out by
means of the recognition of acoustic spectrum patterns.
The prediction system of surface damage has been also developed
using fuzzy rule base in the same way as a human expert.
These techniques may provide unique information for characterising
the process as well as a promise of successful applications
for laser cleaning techniques in real practical fields.
2001 Elsevier Science Ltd. All rights reserved.
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