And Medium-sized Non-spherical Grinding Molding Theoretical And Experimental Research,

The development of modern optical technology makes aspherical optical elements be widelyused in optical system, and the manufacture of large aspherical mirrors often reflects the compositive scientific and technological strength of a country. As an indispensable stage of the manufacture of large aspherical mirrors, the shape error and surface quality of aspherical grinding forming affect the total efficiency of the whole process. In this article some theoretical and technical problems are studied in aspherical grinding forming based on the aspherical optical compositive machine tool(AOCMT). The main content and innovation include:1. The general methods of aspherical grinding are introduced and a unified mathematical model of grinding forming is given. For the grinding of axisymmetric aspherical surface and off-axis aspherical surface the geometric models are derived, and the correctness of the models are proved by experiments; the residual error in grinding process is analyzed and the mathematic condition of avoiding overcutting is deduced.2. The aspherical compound machine tool AOCMT is introduced and its main technical parameters are given.; based on the AOCMT, a unified mathematical model of effects of all the geometric errors to the shape error is established by using the multiple bodies system theory; aimming at the main source of shape error, the practical mathematical model is derived, and their propagation coefficients to shape error are calculated, then the simulation is carried out to get intuitionistic impression.3. The method of on-site measuring is studied, the state of arts of the evaluation theory for geometrical errors and the evaluation sofeware WLEE are introduced. Two methods of software error compensation are introduced and used in the error compensation of aspherical grinding forming. The practical mathematical model is derived and its correctness is proved, the proper weights are determined through a series of experiments.4. Based on the characteristic of aspherical grinding forming, the method of selecting grinding wheels and processing parameters is summarized, and the process flow is introduced. The problem of tool alignment in grinding axisymmetric aspherical surface is solved . Then the other factors affecting the accuracy in aspherical grinding forming are studied and proved by experiments.