Research On Off-line Truing And Measuring Technology Of Bonnet Polishing Tool

With excellent performance, aspheric optical elements are widely used in military and civil products. And the requirements of performance and accuracy are also increased. As the most important and the final procedure of aspheric precision machining, polishing has an important effect on processing quality of aspheric surface. But there are obvious disadvantages in the traditional polishing technology. The bonet polishing as a new developing polishing technology, uses an inflated bonnet as polishing tool, of which the inner pressure can be precisely controlled. And due to the flexibility of bonnet, the polishing tool can fit various kinds of surfaces. In polishing, the profile of bonet tool will influence machining accuracy directly, so it is necessary for the bonnet polishing tool truing.According to the composition and structure characteristic of bonnet polishing machine and polishing tool, the paper proposed an off-line truing and measuring device and study the device design, parameter analysis of truing technology, truing error analysis and measuring method. Firstly, the whole design of off-line truing and measuring device, including mechanical structure and electrical control design, is finished, and the trajectory and the envelope of diamonds on the grinding wheel are analysed to verify the feasibility of the truing device scheme. And then the anslysis by MATLAB simulation is carried out to find the influence on tuing parameters to truing efficiency and trajectory distribution. To obtain the uniform truing trajectory, truing scheme with variable speed ratio is also examined.Further, considered the profile error of bonnet tool, the influence on error radius to curvature, center position and surface accuracy of the bonnet polishing tool are analyzed and compared. And finally, for the whole truing process, the paper puts forward the method of the bonnet tool profile evaluation, solving method of tool curvature radius, data fitting and processing method, which will provide the basis for the evaluation of tool truing.