Advanced Metalworking Solutions for
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Sliding Door Manufacturing Improvements

This project will apply design for manufacturing improvements to reduce cost and weight for the LCS sliding doors. U.S. Navy photo

Objective

The objective of this project is to apply lean manufacturing and design for manufacturing and assembly (DFMA) principles to the existing LCS Freedom Class sliding doors to reduce acquisition cost, weight, and total ownership cost.

Background

The first Freedom Class Littoral Combat Ship (LCS) sliding door ship sets were manufactured under difficult schedule constraints. These door sets are challenging to manufacture because they must meet fire, water-tightness, and pressure loading requirements. Several welds are accomplished in a labor-intensive manner, leading to higher cost and weight than otherwise would be necessary.

Technical Approach

This project is identifying improvements that can be readily implemented in new construction and backward retrofitted to maximize benefits. In order to reduce weight while maintaining structural integrity, the interior components of the door panels are being converted from a conventional plate and stiffener type design to a dual-skinned, engineered sandwich structure built using hybrid laser arc welding (HLAW) technology. To improve corrosion resistance, the materials of construction are primarily corrosion resistant stainless steel (CRES) 2003/2205 with 300 series stainless steel used where material strength is not critical. The project is being performed by an Integrated Project Team comprised of PMS 501; Lockheed Martin; Gibbs & Cox; Marinette Marine Corporation; the Naval Surface Warfare Center, Carderock Division; American Bureau of Shipping; and Navy Metalworking Center.

Benefits

This project aims to reduce labor and assembly costs of the Freedom Class LCS sliding watertight doors. Overall acquisition costs are expected to be decreased by 18 percent per door through improved fabrication methods; additional total ownership cost reductions are projected per hull over the life of the ship for weight savings, improved corrosion resistance, and elimination of painting / re-painting. The improved design also reduces weight by 20 percent over the legacy door. In addition, the redesigned door provides a flat door surface, which reduces installation complexity, weight of the fire insulation blanket, and the number of studs applied.

Implementation

A prototype door will be fabricated and tested in this project. Pending successful completion of all performance evaluations and approval by Gibbs & Cox and PMS 501, the improved door configuration will be implemented. The improved sliding doors are planned for implementation on LCS 9 in late 2013; however, the team is working to achieve early implementation on LCS 7 in July 2013.

Status

Completed

Stakeholder

Anthony C. Smith
PMS 501 Naval Sea Systems Command

Partners

American Bureau of Shipping
Gibbs & Cox
Marinette Marine Corporation
Naval Surface Warfare Center, Carderock Division
PMS 501 Littoral Combat Ship Program Office
Lockheed Martin