Navy Metalworking Center Addresses Thin Plate Panel and Insert Fit-Up Process in DDG 51 Construction

Working with thin steel plates in shipbuilding often creates distortion-related manufacturing issues caused by internal plate stresses and thermal cutting and welding. These distortion issues result in significant rework and added cost. The need to improve the insert and panel fit-up process in order to avoid significant rework and to reduce plate distortion is a priority as the use of thin plate panels is projected to reach 90 percent for future ship construction.

This Navy Metalworking Center (NMC) ManTech project is improving the fit-up and welding of DH-36 thin plate components to produce panels on DDG 51 class ships.
NMC is using a three-step process to install inserts into cutouts of thin plate panels with resultant precise weld root openings:

1. Rapidly measure the insert opening while the plate is being processed on the panel line
2. Use the dimensional output of the opening measurement as an input to a computer numerically controlled or robotic milling cutter to facilitate trimming of the edges of an oversized insert plate to accurately fit into the actual panel opening
3. Develop techniques and tooling, based on insert shape, to minimize distortion during the welding process
    

Project results will reduce fit-up time and improve quality; avoid costs associated with mitigating panel distortion; and enhance panel line capability for DDG 51 class thin panels. Ingalls Shipbuilding estimates saving more than $2.6 million related to the reduction of thin plate distortion over the next five years.
 

The NMC project team will provide a weld process analysis and process improvement report summarizing welding tooling and techniques to minimize distortion of the inserts. The project will also produce a scaled prototype measurement / trimming system that will be built as an implementable station to demonstrate the capability and benefits to the panel insert fit-up process. The results of the project are targeted for integration into DDG 51 class panel lines at Ingalls in Pascagoula, Mississippi, by the end of 2013.

In addition to NMC and Ingalls, the project team consists of the DDG 51 Program Office; Naval Surface Warfare Center, Carderock Division; and the University of New Orleans.