Automated Fillet & Cap Seal

Fillet and Cap Sealing for F-35 Lightning II is currently a labor‐intensive process in which assemblers manually apply sealant to the aircraft using a variety of disposable tips and hand-smooth the material to final shape. This process was very time-consuming and had multiple application issues such as material overflow leading to slump, dripping, voids, and excessive material usage, which increased cost and subsequently increased aircraft weight. This sealant was utilized on a variety of grooves requiring fillet seals and hardware requiring cap sealing on Eddie‐Bolts®. An automated sealant dispensing system had significant potential to reduce labor costs and increase uniformity of fillet and cap seal, which minimized aircraft weight. This Composites Manufacturing Technology Center (CMTC) project, which included Lockheed Martin Aeronautics (LM-Aero) and Encore Automation, implemented a phased approach to develop and demonstrate an automated application system capable of transitioning to production.

The benefits of developing an automated solution for fillet and cap seal have a major payoff in process savings alone, with the additional benefit of potential material and quality savings. Total cost savings for the left / right F-35 Lightning II wings only were estimated at over $7.0M. A follow‐on implementation was expected on center wing, resulting in total F-35 Lightning II cost savings of over $13.7M. In addition, the automation led to decreased variability in total wing weight, which was expected to provide additional weight margin for incorporating new potential capabilities into the aircraft.

Initial implementation is expected at the chosen LM-Aero facility in FY2025 with a follow‐on implementation at an additional LM-Aero facility. Implementation is expected to include procurement of the capital system, performing qualification testing, and any necessary changes to procedures, work instructions, and drawings.

*Prepared under ONR Contract N00014-21-D-7001 as part of the Navy ManTech Program.

*DISTRIBUTION STATEMENT A. Approved for public release: distribution unlimited. DCN# 2024-11-6-309; Approval Date: 11/14/2024