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Flow Forming Bomb Bodies
Navy SBIR 2019.2 - Topic N192-074 NAVAIR - Ms. Donna Attick - donna.attick@navy.mil Opens: May 31, 2019 - Closes: July 1, 2019 (8:00 PM ET)
TECHNOLOGY AREA(S): Weapons
ACQUISITION PROGRAM: PMA201 Precision Strike Weapons
The technology within this topic is restricted under the International Traffic in Arms Regulation (ITAR), 22 CFR Parts 120-130, which controls the export and import of defense-related material and services, including export of sensitive technical data, or the Export Administration Regulation (EAR), 15 CFR Parts 730-774, which controls dual use items. Offerors must disclose any proposed use of foreign nationals (FNs), their country(ies) of origin, the type of visa or work permit possessed, and the statement of work (SOW) tasks intended for accomplishment by the FN(s) in accordance with section 3.5 of the Announcement. Offerors are advised foreign nationals proposed to perform on this topic may be restricted due to the technical data under US Export Control Laws.
OBJECTIVE: Design and develop an alternate manufacturing process capable of producing improved bomb bodies that are less expensive and exhibit higher performance than the current methods, while increasing supplier base and manufacturing technology options.
DESCRIPTION: For decades, the manufacturing method used to produce general purpose and penetrator bomb bodies has been to forge the bomb bodies from steel and use welding and machining processes to complete the bomb case assemblies. General Purpose (GP) (i.e., MK 82, MK 83, and MK 84) bomb bodies are manufactured by heating and pressing welded steel pipes into forge dies and shaping them to the desired shape. After this process is complete, a number of cutting, welding, and machining processes are used to add in all the required parts to complete the case assembly. BLU-109 penetrator cases are made by performing extensive machining on a solid forging, along with additional cutting and welding processes. The forging and machining, welding, and cutting processes required to produce the current GP and penetrator bomb bodies are well defined, but have inherent limitations. GP bombs have very loose tolerance control due to the nature of the forging process used. Penetrator bombs are very expensive to manufacture due to the extensive machining required. Additionally, the current hot-forging process and subsequent heat treatment process utilized for GP bomb production results in relatively poor mechanical property control and repeatability, especially when compared to more modern steel forming processes. This results in a wide band of performance results (e.g., penetration, fragmentation) amongst the population of GP bombs in inventory. Alternate methods of production are being sought to improve the manufacturing consistency, tolerance control, and reduce manufacturing cost. One possible method, Flow Forming (also known as Spin Forming), may provide a solution to both of these issues, as it can hold much tighter dimensional tolerances than the pipe forging process used for GP bomb cases, and may be cheaper than the forging and machining process used for BLU-109 cases. Flow forming would also offer an alternative manufacturing process for GP bombs, enabling an increased supplier base and set of manufacturing technology options.
Flow forming offers much tighter mechanical property control than traditional forging and heat treatment processes. It even offers the ability to tune mechanical properties by adjusting the amount of cold work done on the part during the forming process. This enables flow forming to maintain much tighter control of mechanical properties from unit to unit, and to tune the mechanical properties of a fragmenting case to optimize penetration and fragmentation capabilities.
PHASE I: Design, develop, and demonstrate the feasibility of alternative manufacturing processes (e.g., Flow Forming) for GP and BLU-109 bomb cases. Cases range from approximately 5 feet to 8 feet in length, from 12 inches to 20 inches outer diameter, and from .250 inches to 1.50 inches in wall thickness. A preliminary manufacturing production process flow and tooling plan for the MK82, MK 83, and MK 84 bomb bodies, as well as preliminary cost curves for 500, 2000, and 10,000 units of each case type per year, would be the desired deliverable from Phase I. The Phase I effort will include prototype plans to be developed under Phase II.
PHASE II: Develop a prototype bomb body manufacturing production process. Design and produce prototype MK82 (500-pound class) bomb bodies for qualification testing to determine potential full-rate production costs, uniformity variability, and concentricity. Qualification testing will be performed by the government IAW MIL-STD- 2105, MIL-STD-810, and JMEM lethality and performance assessment tools. Flow formed prototypes must, at a minimum, meet all current production requirements for GP bomb bodies, and meet or exceed penetration and lethality capabilities of current GP bomb bodies. While the goal of this effort is maintain or reduce current production costs for GP bomb bodies, any unit cost increases will be evaluated vs. performance increases to determine the overall value and acceptability to the procuring agency.
PHASE III DUAL USE APPLICATIONS: Conduct further development, prototyping, testing, and Engineering and Manufacturing Development (EMD) transition.
This technology will be commercially applicable for use in fabrication of any metallic axi-symmetric items such as variable-diameter tubing and support poles. Potential applications include automotive, power, utility, and construction industries.
REFERENCES: 1. Wong, C.C., Dean, T.A., and Lin, J. "A review of spinning, shear forming and flow forming processes." International Journal of Machine Tools and Manufacture, Volume 43, Issue 14, November 2003, pp. 1419-1435. https://www.sciencedirect.com/science/article/pii/S089069550300172X
2. Marini, Daniele. "Flow Forming: A Review of Research Methodologies, Prediction Models, and Their Applications." International Journal of Mechanical Engineering and Technology (IJMET), Volume 7, Issue 5, September-October 2016, pp. 285-315. https://pureportal.strath.ac.uk/files- asset/64335735/Marini_etal_IJMET_2016_Flow_forming_a_review_of_research_methodologies.pdf
3. MIL-STD-810G, Department of Defense Test Method Standard: Environmental Engineering Considerations and Laboratory Tests (31 Oct 2008) http://everyspec.com/MIL-STD/MIL-STD-0800-0899/MIL-STD-810G_12306/
4. MIL-STD-2105D, Department of Defense Test Method Standard: Hazard Assessment Tests for Non-Nuclear Munitions (19 Apr 2011) http://everyspec.com/MIL-STD/MIL-STD-2000-2999/MIL-STD-2105D_34120/
KEYWORDS: Flow Forming; Spin Forming; Cold Working; Warhead; Bomb; Axi-symmetric
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