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| The
prototype weld seam facing tools were tested in June 2009 at the
shipyards where DDG 1000 is being manufactured. This photo shows the
tool automatically shaving weld reinforcement on exterior hull panels
on a DDG 51. Photos courtesy of BIW |
Weld Seam Facing Tools Developed
through Navy Metalworking Center Project Delivered to Shipyards
Two prototype (preproduction) weld seam facing tools, which were
developed under a Navy
Metalworking Center (NMC) project, were recently delivered to
Bath Iron Works (BIW) and Northrop Grumman Shipbuilding-Gulf Coast
(NGSB-GC). These tools will greatly reduce or eliminate the need for
manual grinding of certain weld reinforcements on the DDG 1000 class of
ships.
The butt welding of exterior ship panels produces a weld protrusion
that exceeds DDG 1000 fairness requirements. As a result, approximately
23,000 feet of weld reinforcement would have required manual hand
grinding to bring the weld flush with the hull. The manual weld removal
is slow, which increases shipbuilding costs, and the repetitive nature
of hand grinding causes frequent injuries (e.g., carpal tunnel, eye,
back) and costly medical expenses. The cost savings from using weld
seam facing technology for removal of butt welds alone on DDG 1000 is
estimated at $750,000 per hull.
The preproduction tools remove the weld automatically at a minimum rate
of 20 feet per hour versus the current rate of three feet per hour. The
tool is capable of removing the majority of weld reinforcement height
with minimal or no further hand grinding. The preproduction tools now
at BIW and NGSB-GC will enable the shipyards to begin to take advantage
of their benefits, identify potential tool enhancements for future
production tool acquisitions and identify other processes that can
leverage this technology. Currently, a modified version of the tool is
being considered for back-gouging and welding.
The NMC project team consists of BIW, NGSB-GC, General Dynamics
Electric Boat, Naval Surface Warfare Center-Carderock Division
(NSWCCD), DDG 1000 Program Office (PMS 500) and PushCorp, Inc. NMC
developed and validated the weld seam facing tool concept, and
PushCorp, Inc., designed and manufactured the preproduction tools and
is in the process of commercializing the product. The shipyards and
NSWCCD provided technical direction and support to help ensure
implementation.
For more information, contact:
Daniel L. Winterscheidt, Ph.D.
NMC Program Director
winter@ctc.com
814-269-6840
This article was prepared by the Navy Metalworking
Center, operated by Concurrent Technologies Corporation, under Contract
No. N00014-06-D-0048 to the Office of Naval Research as part of the
Navy ManTech Program. Approved for public release; distribution is
unlimited.
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![[NMC Image]](http://nmc.ctc.com/images/header_logo.gif){kind=logo}
