| Along with the rapid development of space optical system, the lightweight requirements for optical components are more and more critical. Compared with traditional optical materials, the specific stiffness of SiC is much bigger. If the structural dimension is the same, the lightweight extent of SiC components is the highest. Furthermore, SiC have these merits of low thermal distortion, excellent optical performance, isotropy, innocuity and molding for complex shape. Accordingly, SiC is the first of all optical materials which are made for space mirrors.As a kind of polyphase ceramics, SiC is very hard and crisp. It is difficult to accurately machine SiC components. At present, the shape precision of SiC mirrors can't still meet the requirement for high-precision optical system, and this status restricts their application. Consequently, it is a key issue to research the processing property of SiC materials. In this dissertation, quantificational lapping and polishing technologies of SiC materials are thoroughly studied. The main content and innovation include:1. The shaping principle and removing feature of SiC materials in plane polishing process are studied. The mathematics model of workpiece's relative motion path is founded. When the eccentricity distance is different, the distribution form of average pressure density in machining zone is given. In the lapping and polishing experiment, SiC materials can be evenly removed by choosing reasonable process conditions and parameters, and the surface will convergence to prefect shape. This is helpful to the study on quantificational machining technologies of aspheric components.2. The machining manners and error convergence characteristic in computer controlled optical surfacing (CCOS) are analyzed. Dual-rotors machinery is developed, and its removal function distributes as Gauss curve. The solution formula of dwell time is deduced by using the pulse iteration method and the smoothing Fourier transition method, and the formula can be simplified referring to workpiece shape. According to the anastomotic status of the tool and workpiece surface, we present the new model of the inherent relation among local pressure density, removal rate, convergence ratio and residual errors, and the corresponding formulas are given. The forming cause of the edge effect in the polishing process is analyzed, and the means which reduces the edge effect is put forward.3. Aspheric optical compound machine tool (AOCMT) which integrates grinding, lapping and polishing is developed. The influences of motion errors on grinding accuracy are analyzed. According to homogeneous coordinate transition model, the postposition processing algorithm in multi-axis numerical control machining is deduced. Based on 5-axis NC linkage, AOCMT can generate freedom-form surface in normal manner, and grinding accuracy is better than 8 m.4. According to the error component of various wavelength, feeding step length, convergence ratio and anastomotic status, a new method which determines the dimension of thepolishing tool is presented. The tool's path planning is profoundly studied. Process flows and technical specifications in CCOS are also established.5. Magnetorheological finishing (MRF) is a new style machining technology of super-smooth optical surface. The stability, rheology, chain structure and consecutive medium model in magnetorheological fluids are analyzed. According to the contribution of shear stress and normal pressure in polishing zone, the quantificational machining model of MRP is presented. As an example of plane workpiece, the influences of machining parameters on removal rate and surface roughness in MRP are studied.
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