What's it about?

Hard ceramic conformal windows and domes provide challenges to the optical fabricator. The material hardness, polycrystalline nature and non-traditional shape demand creative optical fabrication techniques to produce these types of optics cost-effectively. VIBE™ is a high-speed, high-pressure, conformal optical fabrication process that is capable of rapidly polishing hard ceramic materials and non-traditional shapes such as toroids and tangent ogives. This paper will overview the recent progress made to rapidly manufacture hard ceramic conformal windows and domes as well as the challenges associated with it. Results will show 10-50x increase in removal rates using the VIBE platform to polish hard ceramic materials compared to conventional methods.

1. CONFORMAL WINDOWS AND DOMES

Conformal windows or domes on air vehicles will improve aerodynamic, mechanical, electrical or thermal performance [1]. The conformal window is an optic that conforms to a surface shape, for example the fuselage of a plane or wing of an aircraft. The aerodynamic dome can replace a hemispherical dome that covers the front of the missile seeker[2]. The aerodynamic shape allows for reduced drag [1] and lower probability of failure due to rain or sand erosion by decreasing the impact angle[3]. The shape of the conformal dome might be an ellipse, hyperbola, spline or other aspheric formulas that produce a higher fineness ratio[4]*. As the fineness ratio increases the drag induced by the dome decreases[2]. Figure 1 shows a graphical representation of the drag coefficient versus the dome fineness ratio for spherical and conformal domes at Mach 2.