From: Terry T. Wohlers (firstname.lastname@example.org)
Date: Mon Jul 29 2002 - 05:38:01 EEST
A friend forwarded the following article to me. Some of you may find it of
Wohlers Associates, Inc.
OakRidge Business Park
1511 River Oak Drive
Fort Collins, Colorado 80525 USA
July 15, 2002
The Army's Secret Weapon: Repair Shops In The Field
These mini-factories can make and fix gear near front lines
Soldiers in medieval times would wage war attended by a retinue of
blacksmiths. Their job: to iron out the dents and dings in their
bronze-plated armor and repair their weapons.
Now the U.S. Army is updating that concept with a mobile factory that can
roll, fly, or float into battle. But instead of anvil, hammer, and tongs,
the Army's factory-to-go uses cutting-edge computerized tools to fuse
powdered metals into solid replacement parts for disabled weapons and
broken vehicles. The tools can even analyze and fabricate components no
longer being made.
The Army has spent more than two years and $16 million to create these
futuristic, smart-manufacturing platforms known as Mobile Parts Hospitals.
The task of putting together the MPHs was assigned to the Army's National
Automotive Center and its partner, Focus:HOPE, a training center
specializing in advanced machining technologies. To speed MPH development
while holding down costs, the Detroit-area team has focused on testing,
shrinking, and toughening up commercial machine tools selected for their
The real inspiration for MPHs, however, isn't machinery, but medicine. It's
the Mobile Army Surgical Hospital (MASH) units featured in Robert Altman's
1970 film. Such units revolutionized wound treatment in the 1950s, and the
MPH is poised to do the same for battlefield repair. The latest prototype,
built earlier this year, occupies a 20-ft. long container--narrow enough to
fit in a standard C-130 military transport plane. "The goal is to be able
to deploy anywhere in the world in short order," says Coryne Forest, a
civilian manager of the MPH program.
High-speed computer modeling and rapid prototyping are the key technologies
in MPH. Suppose, for example, a soldier shows up with a snapped tie-rod, a
steel part used to connect vehicle components. A technician checks to see
if digital blueprints for the rod are available, either on board or by
satellite-link from a U.S. maintenance center. If not, he sets about
reengineering the broken rod. First, he uses a 3-D laser scanner to create
a software model of the part. In about an hour, the tool, made by Israel's
Nextec Ltd., generates a "cloud" of spatial data points that define the
tie-rod's shape. Computer-aided design software then stitches this network
into a virtual model accurate to a few microns.
Next, the tie-rod data are fed to a machine called a laser engineered
net-shaping (LENS) tool, made by Albuquerque's Optomec Inc. By depositing a
fine path of powdered metal, it traces a cross section of the
part-in-progress. Trailing behind is a computer-controlled laser that fuses
and hardens the metal particles. Layer by layer, more material is fused
into place, so that--at a rate of about one cubic inch of material per
hour--a new part emerges from the smoke and dust. Once the rough spots are
ground off by a robotic milling machine, the part is ready to go. While the
tools aren't new, the labs' compactness and mobility is novel and
significant, says George Fadel, a mechanical engineering expert at Clemson
University in Clemson, S.C.
There are some limits. For one, the LENS machine can't yet mix materials in
one component. Also, the parts fabricated so far have been no bigger than
one cubic foot. And it takes about six hours of processing to make an
object that size.
But that's far better than the weeks or months required to fetch a part
from the U.S. What's more, the MPH promises to solve one of the military's
trickiest repair problems: how to replace discontinued parts. "Our legacy
fleet includes heavy vehicles first made as far back as the '40s," says
Forest. "Sometimes, the original manufacturer no longer exists." And some
older gear is made with materials such as uranium that is now blacklisted
because of toxicity. In such cases, the do-it-yourself approach of the MPH
may be the only way out of a rut.
To support the MPHs, the Army is considering some ambitious backup
infrastructure. It's developing the first of three planned agile
manufacturing centers that will be able to whip up replacement parts too
big or complex for the MPHs. By 2007, these centers could be connected by
satellite to a fleet of MPH units in the field, allowing specialists to
help the MPH crews diagnose tough problems.
If the Army can make it work, this on-demand manufacturing model could
someday show up in extreme commercial environments as well. "Think of an
offshore oil rig, a mine--or even space travel," says Forest. Until then,
though, the real action will be on the front lines.
By Adam Aston in New York
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