Hull Fairness & Accuracy Control
Project Participants: Northrop Grumman Shipbuilding-Gulf Coast
Project Start: November 2007
Hull fairness/flatness and accuracy control requirements for DDG-1000 create a unique production challenge for Northrop Grumman Shipbuilding-Gulf Coast (NGSB-GC). Currently there is no technology solution that would meet these restrictive fairness fabrication requirements as they are more stringent than requirements for DDG‑51. With the DDG‑1000 design concept demands, NGSB-GC must explore the latest measurement technologies and their associated software applications to develop procedures that will provide more accurate results while decreasing the amount of labor required by the existing photogrammetry systems.
The purpose of this two-phased project was to investigate and implement the expanded use of metrology instrumentation during the shipbuilding process at NGSB-GC. The two key areas investigated were near-term training on the expanded capabilities of existing systems and new technology, equipment and software to meet more stringent requirements in a more efficient process for future naval ships. Phase I was a 12-month effort with three tasks: Requirements and Capability Survey (1 month), Process/Capability Improvement (2 months), and an expanded Inter-Sector and Market Technology Research (9 months). Phase II was a 12-month effort that field tested 3 technology systems (laser scanning, multi-camera photgrammetry and laser tracking), evaluating a multitude of technology applications.
Upon completion of field testing and evaluation, the API Laser Tracker 3 was selected for capital purchase by NGSB-GC for its versatility, relatively small footprint and portability, familiarity of software, accuracy, and overall ease of use within the manufacturing environment. This equipment was also shown to benefit other areas of the shipyard unrelated to hull fairness, as evidenced by its role in the calibration and installation of machine shop components. This “all purpose” nature of the Laser Tracker has prompted NGSB-GC to plan for the purchase another unit, for use in other applications such as combat systems alignment and calibration of precision machinery.