Accelerated Reconnaissance Window Development

Grinding is used to satisfy figure and finish requirements for optics, removing successive layers of material to ensure alleviation of any damage created from the prior operation. Consequently, fabrication times are slow and expensive. The optics manufacturing industry currently lacks physics-based models needed to understand the impact of process and material variables on final part quality and costs. As a result, there exists a limited ability to improve these material removal processes. Our goal is to provide high throughput, low cost grinding processes enabled by physics-based modeling for accelerated development of reconnaissance windows. We will advance the physics-based machining models to simulate grinding in ceramics. Our AdvantEdge FEM software will provide the baseline technology to be enhanced for grinding process modeling. Technical objectives include: (1) advancing physics-based machining modeling for grinding of AlON, (2) validating physics-based model and (3) demonstrating process improvements for AlON via simulations. Anticipated results will demonstrate physics-based models to: (1) reduce per part lead times and grinding costs of optical windows by 50%, (2) enable high rate, low cost manufacture of optics, (3) eliminate expensive, time consuming trial-and-error process development, and (4) accelerate the insertion of new optical materials via significant reductions in process development time. BENEFIT: Selection of fabrication method for constructing aerial reconnaissance and airborne sensor windows are tightly coupled with the choice of the materials, the sizes of the optics and desired costs. Considerable resources are spent in making material choices, performing trial-and-error tests, and developing specialized equipment for proving out the product and process design. Insertion of new optical materials is frustrated by the slow pace of process development, thwarting their ability to achieve full potential. In optics manufacturing, the need for better figure and finish for the final surface – along with reduced subsurface damage and per-part costs – imparts special challenges on the grinding process design. Difficulty in observing material removal mechanisms during grinding makes it difficult to understand and control process factors that influence the final part quality. The goal of this project is to develop a first-principles, physics-based modeling approach that will allow for the identification of high-opportunity process operating envelopes and new tooling innovations, which would otherwise not be achieved without expensive, time-consuming trial-and-error approaches. Anticipated long-term benefits of the proposed research will improve the cost and performance of optical systems through improved understanding of material behavior under grinding and reduced process development costs. Commercial and societal benefits of this proposal include increased product performance and reduced manufacturing and maintenance costs for a variety of military and civilian optical systems. Benefits will be realized through: • Reduced component lead times and grinding costs of optical windows via high throughput grinding process • Elimination of expensive, time consuming trial-and-error process development • Process innovation enabled within the industry through validated digital simulation • Utilization of a highly automated, repeatable manufacturing process for a variety of optical materials and applications • Accelerated insertion of new optical materials via significant reductions in process development time • Validated, generalized physics-based models that can be readily applied to a wide range of optical sizes, geometries and materials • Advanced knowledge of material removal mechanisms in optical grinding In addition to the direct commercial benefits to industry, this project will: » Further increase the science and engineering knowledge base in both industry and academia regarding the fundamental relationships between materials, processes, and product quality; and » Remove significant cost barriers that exist when investigating truly innovative manufacturing methods and implementation thereof.