Adaptable Five-Axis Polishing Machine Head

Introduction A growing demand on machining high precision aspherical and free-form optics derives from the continuous development of computer-assisted calculation and simulation methods and therefore improved possibilities of integrating numerous optical functions within one and the same lens or mirror. Applications include illustration as well as sophisticated illumination optics. State-of-the-art calculation methods enable the optical designer to create a free-form shape, detouring a coherent light beam into an image consisting of a well defined distribution of bright and shady regions. Production technologies for such high quality surfaces are the current limiting factor. The diamond machining is pursuit in a number of research activities, still being constricted to nonferrous or plastic sample parts. The alternative approach is the grinding and the subsequent polishing process, accessing a wide spectrum of applicable materials [Fig. 1]. Whereas the plane polishing of flat and spherical optics is a well established technology, the ultraprecise zonal polishing for the form correction of aspheric or free-form surfaces is still not developed to the point, where it can be used in industry as an ecconomically established process. Reasons for this drawback are the lack in the detailed chemo-mechanical process-understanding to deterministically predict or even closely control the local material removal on the optical part.