Conformal Sensor Window

Ceramic transmission sensor windows offer advantages over axisymmetric surfaces in the ability to reduce drag and weight. Materials of interest include spinel, polycrystal alumina, and AlON. However, the description, fabrication and metrology of these surfaces can be costly, or even impossible. Fabrication of these surfaces is difficult, since they are not axisymmetric and can have varying local radii of curvature, rendering grinding, lapping and polishing of these surfaces untenable. A method to overcome these difficulties in fabrication is to apply ductile mode machining (DMM) to eliminate grinding, lapping and polishing. DMM has been successfully applied to spinel, AlON and sapphire in Phase I. Through the use of physics-based modeling, DMM conditions can be identified where material removal results in ductile chip formation, damage free surfaces and excellent surface finish. This SBIR activity extends the technology of DMM to transmission optical materials enabled by physics-based modeling technology. We will further develop and enhance its modeling capability for application to spinel workpieces. In Phase II we will demonstrate DMM of a spinel lens and perform the requisite metrology.