Surface Finising Polycrystalline Alumina Missile Domes

Increasing missile velocities coupled with higher sensor performance requires commensurate improvements in dome performance. Cutting large sapphire crystals into hemispherical domes has become a commercially viable, though relatively expensive, business. The machining and polishing of sapphire into more aerodynamic dome shapes, such as an ogive, is a much more difficult and expensive endeavor. Given the difficulty of single point turning of hard materials for ogive domes, CeraNova's team is proposing an alternative approach. The proposed approach involves applying a technology which is routinely used to grind precise shapes with highly polished surfaces from hard ceramic materials. This technology is an economical commercial manufacturing method that offers acceptable material removal rates, ultra-high precision, and optical quality surface finishes. Experience with this unique, practical method of machine finishing makes us highly confident that it is a viable and economical method for grinding missile domes with ogive shapes. CeraNova also proposes transparent polycrystalline alumina (PCA) as an alternative material for this application. CeraNova recently demonstrated a low-cost, powder processing route for producing transparent, fine-grained PCA that has the potential to meet or exceed the capabilities of sapphire in demanding infrared missile dome applications.