DETERMINISTIC HIGH SPEED GRINDING OF SAPPHIRE DOMES

Sapphire, and other hard brittle materials, are highly regarded as missile domes because of their high mechanical strength and thermal characteristics. Conventional finishing processes used to provide for the final configuration of the domes can be as much as 50 percent or more of the total cost. A new fabrication process for sapphire domes is proposed to reduce the cost of grinding from a scooped dome blank to a prepolished stage by 20 to 30 percent. Specialized sapphire grinding tools and abrasives will be integrated with the high speed, statistically controlled CIM prototype system currently in use at the University of Rochester. The OPTICAM System had already demonstrated a 20 to 30 percent reduction in the fabrication times for several common glasses. A new fabrication process for grinding a saphire dome to a prepolished condition will be developed and tested. We seek to prove that a similar time reduction can be achieved in sapphire. A second sapphire dome will be fabricated from a scooped blank to the same accuracy using conventional methods. These times will be used as a baseline for evaluation of the high speed technique.