Ogive and free-form polishing with ultraform finishing

Abstract

UltraForm Finishing (UFF), OptiPro Systems' five axis sub-aperture polishing machine has evolved from an initial prototype into a robust aspheric manufacturing system that can rapidly produce finished aspheres directly from a ground surface. UFF utilizes a belt of polishing material 50" long supported by a polyurethane wheel to polish a wide variety of materials ranging from traditional glasses to IR materials. This belt polishing system provides a tuned stiffness that is capable of conforming to the polishing surface without replicating the surface roughness. When combined with state of the art figure correction algorithms, the UFF is capable of robust and deterministic figure correction for aspheric surfaces. Recently, OptiPro Systems has expanded the capability of the UFF to include deep concave ogive and free-form surfaces. Although these types of surfaces can be beneficial from an optical or aerodynamic standpoint they pose additional challenges both from their steep geometry as well as from a polishing tool path perspective. A brief description of these challenges as well as possible solutions to these problems will be presented. In addition, the current figure correction capability of the system utilizing feedback from OptiPro's five axis non-contact free-form metrology system will be presented.