Prototype of a fiber optic sensor for online measurement of coating thickness

Giulio D'Emilia

doi:10.1117/12.364282

21 September 1999 Prototype of a fiber optic sensor for online measurement of coating thickness

Giulio D'Emilia

Proceedings Volume 3824, Optical Measurement Systems for Industrial Inspection; (1999) https://doi.org/10.1117/12.364282
Event: Industrial Lasers and Inspection (EUROPTO Series), 1999, Munich, Germany

Abstract

In this paper the experimental characterization of a transducer for on line measurement of coating thickness in food industry applications is described, which is composed by a fiber optic probe and by an eddy-current proximity one. The method is based on measuring reflectance by a fiber optic probe of the coating plated on thin steel sheets. The eddy current proximity probe should be used to measure the substrate position. In order to evaluate the feasibility of this approach, a particular attention has been paid to the accuracy of the method, since an accuracy in the order of plus or minus 1 micrometer should be achieved for practical interest. With this aim, the effect of the main interfering and modifying quantities of geometrical (sensor size, probe head angle of incidence, working distance, ...) and optical (light source and photo-detector behavior stability, ...) type has been evaluated both theoretically and experimentally by using a calibration test bench in stationary working conditions. Furthermore, a calibration test bench has been built, where a translating and vibrating steel plate is realized, in order to evaluate the effect of translation velocity of the plate and also of cross vibrations. Results of dynamic calibration are also described and discussed, in order to get information about the final sensor configuration.

Citation Download Citation

Giulio D'Emilia "Prototype of a fiber optic sensor for online measurement of coating thickness", Proc. SPIE 3824, Optical Measurement Systems for Industrial Inspection, (21 September 1999); https://doi.org/10.1117/12.364282

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