3次元形状を有する鋳物表面粗さ光学式測定法の開発

概要

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A machine for automatic measurement of the surface roughness of 3-dimensional cast, metals using an optical noncontact, method has been developed. The specimen is illuminated from eight surrounding directions with the incident angle of 60° and detected by a CCD camera, perpendicular to the surface. The surface roughness R_a can be obtained from the contrast, C , which is calculated using the image detected by the CCD camera. First, the specimen is positioned at an angle of O° , 45° or 90° with respect to the x axis. Second, at each of these positions, the images of the specimen are detected , by the CCD camera by rotating the specimen in steps of 45° between O° and 360° around the z'axis. The regions to calculate the contrast C for each image are obtained from the shape data of the specimen which are measured using a 3-dimensional coordinates measuring machine. In the experiment, the specimen is illuminated from eight surrounding directions using 100W halogen lamps and Fresnel lenses, and the surface roughness R_a at various regions on the specimen is calculated. As a result, , the surface roughness of good or defective specimens is measured with an error less than ± 25 %.
公益社団法人精密工学会の論文
1999-03-05