Development of manufacturing technologies for hard optical ceramic materials

Abstract

Hard ceramic optical materials such as sapphire, ALON, Spinel, or PCA can present a significant challenge in manufacturing precision optical components due to their tough mechanical properties. These are also the same mechanical properties that make them desirable materials when used in harsh environments. Premature tool wear or tool loading during the grinding process is a common result of these tough mechanical properties. Another challenge is the requirement to create geometries that conform to the platforms they reside in, but still achieve optical window tolerances for wavefront. These shapes can be complex and require new technologies to control sub aperture finishing techniques in a deterministic fashion. In this paper we will present three technologies developed at OptiPro Systems to address the challenges associated with these materials and complex geometries. The technologies presented will show how Ultrasonic grinding can reduce grinding load by up to 50%, UltraForm Finishing (UFF) and UltraSmooth Finishing (USF) technologies can accurately figure and finish these shapes, and how all of them can be controlled deterministically, with utilizing metrology feedback, by a new Computer Aided Manufacturing (CAM) software package developed by OptiPro called ProSurf. .

Modeling and Experimental Verification of Time-Controlled Grinding Removal Function for Optical Components

“…OptiPro Systems of the United States and the University of Rochester proposed a kind of wheel belt deterministic polishing technology, named UniForm Finishing (UFF) [ 15 ]. Fess et al [ 16 ] used UFF to process a sapphire window in 70 min, and the surface shape error converged from RMS 0.18 λ to RMS 0.028 λ. Liu et al [ 17 ] proposed a two-dimensional elliptical vibrating abrasive belt grinding (2D-EVBG) technology. The machining results show that lower surface roughness will be obtained with the increase in grinding depth and workpiece feed speed, which is also more likely to lead to brittleness removal for quartz glass.…”