High-speed photography applied to the laser-cladding process

Fabrice Meriaudeau; Frederic Truchetet; Christophe Dumont

doi:10.1117/12.273390

28 May 1997 High-speed photography applied to the laser-cladding process

Fabrice Meriaudeau, Frederic Truchetet, Christophe Dumont

Proceedings Volume 2869, 22nd International Congress on High-Speed Photography and Photonics; (1997) https://doi.org/10.1117/12.273390
Event: 22nd International Congress on High-Speed Photography and Photonics, 1996, Santa Fe, NM, United States

Abstract

The laser cladding process consists in adding melting powder to a metallic substrate. The process usually involves the delivery of fine grained alloy powder blown into the melt pool during the laser irradiation. The temperature of the grains when they reach the surface and their speed within the laser beam are extremely correlated and influence on the quality of the coating. We present three methods which can be used to measure the speed of the particles in the powder stream; they all make use of digital images obtained with a standard matrix CCD camera and a strobed lighting. The first method, which we call the basic one, allows speed measurements in a slim cross section of the powder stream. Thanks to its low requirement in calculation amount we were able to implement it in a strictly software design for real time application (1 image/20 ms). In the second method we work on the Fourier transform plan of a strobed image, between two flashes the particles have moved from the same distance this periodic distance represents a specific frequency which is estimated in the Fourier space. In the third method, we strobe the image using three color filters and obtain a RGB image. The autocorrelation function of the image provides us with information related to the speed of the particle. The particularity of the two last methods is their complementarity. Indeed, the FFT gives good and averaged results for wide area, it is a large scale method. At the opposite, the three colors imaging method is powerful for small scale study.

Citation Download Citation

Fabrice Meriaudeau, Frederic Truchetet, and Christophe Dumont "High-speed photography applied to the laser-cladding process", Proc. SPIE 2869, 22nd International Congress on High-Speed Photography and Photonics, (28 May 1997); https://doi.org/10.1117/12.273390

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