Analysis Of Measuring Curved Surface Roughness Method Based On Oblique Laser Scattering Style

Surface roughness has a great influence on the performance of the products. Due to the rapid development of mechanical, electronic and optical industries, the surface quality requirement of precision products is increasing day by day and the measurement of surface roughness was more and more important due to the miniaturization of industrial. Measuring surface roughness by optical has advantages of non-contact, no damage and high accuracy. However, for some curved surfaces in complex cases such as the narrow space, surface roughness measurement is difficult to achieve due to the optical probe is difficult to approach the surfaces.Aiming at the problems of roughness measuring on curved surface in narrow space, the relationship between the measurement voltage value and the curved surfac e roughness was researched, and a roughness measuring system based on oblique laser scattering style was proposed. The system measuring principle based on light scattering was analyzed and the curvature was regarded as an important factor for the optical characteristic value for first time,at the same time the fiber optic sensor for the system was designed for the system.The system measuring principle base on light scattering was analyzed and the curvature was regarded as an important factor to the optical characteristic value for the first time.At the same time,a fiber sensor was designed for the system.Aiming at the measurement requirements,the motion control and data acquisition function for the curved surface roughness measurement system was designed,and feedback neural network was processed to optimize the data.Through the experiments,the relationship among the parameters of the measurement voltage value, the incident angle of the laser, the distance between probe and target surface and the curvature of measured surface was established. And through the calibration experiment, the characteristic curve between the roughness value and the measurement voltage value was obtained, and the curve is monotone and coincides with the result of theoretical analysis. At last, roughness measurement experiments were carried out by using the test rig. The results indicate that the proposed method is certain feasible, and the measurement error could be controlled below 5% compared with the stylus method, it can achieve the requirement of measuring the curved surface roughness in narrow space.