Reconstruction And Evaluation Of Surface Topography Of Optical Surface

Aspheric surface and free-form surface optical components can effectively correct the aberration, improve imaging quality, expand the field of view of the optical system,greatly simplify the structure of the optical system and reduce weight which makes the demand of aspheric surface and free-form surface optical components is increasing in the military, medical, aerospace and other industries. However, due to the complicated geometrical and optical properties of the aspheric surface and the optical free-form surface, the difficulty of the design, processing and evaluation of the surface is greatly improved which greatly limits its development in civil field. So it is very necessary to study the reconstruction and evaluation of the surface topography of the aspheric surface.In recent years, three-dimensional elliptical vibration cutting is considered to be the most promising processing method because of its specialty of friction reversal and intermittent cutting, which has a broad application space. However there are few reports on the evaluation about the three dimensional elliptical vibration cutting surface, therefore based on the research of measurement and reconstruction technology, this paper has carried out the research on the detection and evaluation of the surface topography of 3D elliptical vibration cutting.Firstly, in this paper, we set up the experimental platform for in-situ measurement and complete the trajectory planning. In-situ measurement of the surface topography of elliptical vibration cutting is realized by means of in-situ measuring device and the moving least square method is used to fit the measured data points, and the fitting method is obtained. The surface shape is obtained by the radius error compensation of the reconstructed surface, which lays a foundation for the evaluation of the optical surface.Secondly, by means of wavelet packet analysis, the high frequency error(surface roughness) and low frequency error(surface roughness) of surface topography are obtained by wavelet packet decomposition and reconstruction. Based on wavelet packet analysis and through the calculation of surface roughness, PV value, mean square error and other surface evaluation parameters, the influence of vibration parameters on the surface morphology of elliptical vibration cutting is revealed and the selection of vibration parameters in cutting process is analyzed quantitatively.Finally, research on cutting parameters based on the three-dimensional elliptical vibration, choose the main parameters affecting the surface topography of the three dimensional elliptical vibration cutting and carries on the variable design. The variables are constrained according to the actual cutting conditions of the three-dimensional elliptical vibration cutting parameters. Regarding the maximum residue height as the optimization goal, we established the three-dimensional elliptical vibration cutting parameter optimization model. Through genetic algorithm optimizes the elliptical vibration cutting parameters, provide certain theoretical guidance for practical machining.