Applying DFM improvements will reduce construction costs and improve performance for VCS weapons cradles. U.S. Navy photo
To improve the producibility of weapons cradles and reduce costs, the Integrated Project Team (IPT) will apply lean manufacturing and design for manufacturing principles to the complex design of the VCS weapons cradle.
VIRGINIA Class (SSN 774) submarine (VCS) weapons cradles are complex assemblies manufactured using extensive welding and machining processes. This complex design must be simplified in order to reduce cost and eliminate unnecessary labor to support the manufacturing rate required by the VCS Program. However, system performance must not be impacted.
This project anticipates an estimated cost savings of $60K per cradle or $1.1M per submarine hull. Overall, for a five-year period and 10 hulls, the estimated total cost savings are $11.1M.
Improvements include an estimated 30-part reduction, based on the planned configuration; improved quality, reduced rework and reduction in weldment fabrication times, with a projected 30 percent shorter build time for the machined cradle weldment; as well as product simplification and improved manufacturing consistency and repeatability. In addition, the improved quality will contribute to fewer engineering waivers and reduced scrap costs.
Implementation will occur on VCS at NNS and GDEB. The end block consolidation, balanced weld joint, and improved dimensional tolerance process improvements are on schedule for SSN 786 / 787 insertion in 2013. The welding system and fixturing hardware developed under this project will be transferred to NNS and will be used to build a full-scale prototype weldment to validate the improvements. Collective prototype and manufacturing process improvements, including gusset standardization and reduction is planned for implementation on SSN 789 (February 2014) or possibly SSN 788 (October 2013).
General Dynamics Electric Boat Corporation
Naval Surface Warfare Center, Carderock Division
Newport News Shipbuilding
PMS 450 Virginia Class Program Office
Naval Undersea Warfare Center- Newport