Lightweight Silicon Carbide Mirrors via Binder Jet Additive Manufacturing

The United States Navy has identified a need for improved manufacturing methods and materials for optical mirrors for use in space based, next generation microsatellites. Additive Innovations, LLC is proposing to develop a silicon carbide material for lightweight mirrors using Binder Jet Additive Manufacturing (AM) to meet the goals set forth by the Navy. Optical substrate materials can vary from metals, to glass, to ceramics, and even composite materials. Silicon carbide (SiC) is an ideal optical substrate material due to its low density, high stiffness, low coefficient of thermal expansion and high thermal conductivity. The thermal properties of SiC are ideal because thermal gradients during service will be quickly dissipated, and thermal expansion is low thereby maintaining optical performance. SiC has, however, been traditionally expensive and difficult to manufacture because it cannot be readily machined. Mold processes can be expensive with high tooling costs amortized over one or very low quantities.  SiC also is non-toxic, doesn’t outgas, and is slightly electrically conductive. An additively manufactured silicon carbide mirror substrate can meet material requirements and overcome traditional manufacturing challenges.