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Reduced Cost Fabrication of Optical Sapphire Hyper-hemispheres for Submarine Masts
Navy SBIR 2016.1 - Topic N161-036 NAVSEA - Mr. Dean Putnam - [email protected] Opens: January 11, 2016 - Closes: February 17, 2016 N161-036 TITLE: Reduced Cost Fabrication of Optical Sapphire Hyper-hemispheres for Submarine Masts TECHNOLOGY AREA(S): Materials/Processes ACQUISITION PROGRAM: PMS435, Submarine Electromagnetic Systems OBJECTIVE: Develop a cost effective set of tools or processes for fabricating sapphire hyper-hemispheres or similar shaped optical window components. DESCRIPTION: The Navy is developing multi-spectral imaging masts, modules, and components that exist outside the pressure hull of a submarine. The appropriate material selection for optical windows for multi-spectral (visible and infrared) systems is limited, consisting of a variety of ceramic materials as well as industrial sapphire that produce affordable submarine imaging mast components. However, these materials are expensive to manufacture into multi-spectral windows. In addition, some optical windows exist in systems covering large fields of view, which results in curved windows similar in construct to a fish eye lens. These shapes add additional challenges to the manufacturing process. Sapphire is currently the most technically mature material for multi-spectral windows. Sapphire is a very hard material and very expensive to grind to shape when dealing with curved surfaces and components of the thickness required in a subsea environment. The Navy seeks to develop innovative machining tools or processes to reduce the time of grinding a hyper-hemispherical window by 50% in order to produce affordable submarine imaging mast components to support future production programs. This would lead to multi-million dollar savings in production costs. Examples include ultrasonic machining and laser based machining (references 1 and 2). Appropriate ways to reduce cost would include objectives such as increasing the material removal rate during grinding or decreasing downtime to perform in-process metrology during fabrication. In addition, use of sapphire for hyper-hemisphere will lead to life cycle support cost avoidance of greater than $10M due to the inherent durability of the material. The normal development process of any optical component would consist of grinding the raw materials, polishing, and coating. These new innovative machining tools or processes would replace the current grinding process. PHASE I: The company will develop a concept for a set of tools or processes for grinding multi-spectral windows to specific shapes for which drawings will be provided. The company will demonstrate the feasibility of the concepts in meeting Navy needs. In addition, the company will present calculations of the time required for sapphire (multi-spectral window) grinding. Sample material grind or analytical modeling will establish design feasibility. Phase I Option, if awarded, will include the initial layout and capabilities description for the process or tools in Phase II. PHASE II: Based on the results of Phase I and the Phase II Statement of Work (SOW), the company will develop a prototype of the tools or processes for grinding sapphire to specific shapes for evaluation as appropriate. This tooling will be used to manufacture an Optical Sapphire Hyper-hemisphere to demonstrate the cost reduction. The prototype tools or process will be delivered at the end of Phase II. The company will prepare a Phase III transition plan to transition the technology to Navy use. PHASE III DUAL USE APPLICATIONS: During Phase III the company will support the Navy in transitioning the process for manufacturing of Optical Sapphire Hyper-hemispheres for Submarine Masts technology to Navy use for the Task Oriented Technology Insertion Mast (TOTIM) program. The company will utilize the developed process to manufacture and thoroughly evaluate optical window components for evaluation to determine the effectiveness in an operationally relevant environment. Commercial use of this technology includes sapphire lens and window development. Sapphire is rapidly becoming a commonly used optical component that must be produced at lower cost across all elements of its development. REFERENCES: 1. Mahmud, Yaseen; Morgan University, "Ultrasonic Machining", April 1999; http://www.eng.morgan.edu/~mahmud/IEGR563/ultra.html 2. Purcher, Jack, "Apple Reveals Laser Cutting Techniques for Processing Sapphire", 20 March 2014., http://www.patentlyapple.com/patently-apple/2014/03/apple-reveals-laser-cutting-techniques-for-processing-sapphire.html KEYWORDS: Hyper-hemisphere; multi-spectral head window; sapphire head window; ultrasonic machining; laser based machining; imaging mast TPOC-1: Jose Barbosa Phone: 401-832-7032 Email: [email protected] TPOC-2: Eric Rabe Phone: 401-832-8037 Email: [email protected] Questions may also be submitted through DoD SBIR/STTR SITIS website.
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