Robotic Waterjet Systems
In the late 1970s, before the Space Shuttle made its flight
debut, NASA recognized a problem in the fact that the Shuttle's
two solid rocket boosters were reusable; they were designed to
operate for two minutes on a Shuttle mission, then separate and
drop Earthward to a parachute-softened splash in the ocean for
recovery and refurbishment.
The problem lay in the refurbishment process: how to strip
away multiple layers of tough, removal-resistant paint and thermal
protection material, and do it in such a manner that the booster's
casing would not be damaged. Clearly, NASA saw, something substantially
more advanced than conventional manual stripping would be required.
The Ship ARMS Decoating System employs a high pressure water
pump to strip unwanted coatings from large ships and other vessels.
Marshall Space Flight Center (MSFC) teamed with United Technologies'
USBI Company, Huntsville, Alabama, NASA's contractor for booster
refurbishment, to develop an advanced stripping system based
on hydroblasting, or high pressure waterjet cleaning. To compress
eight years of complex research and innovative development into
a paragraph, the NASA/USBI team developed a waterjet capable
of slicing through the thermal protection material and blowing
away the particles; found a way to regulate the jet stream to
strip paint and primer beneath the outer protective coating,
one layer at a time; and developed a computer-directed six degrees
of freedom robot for precise control of the waterjet, in order
to prevent damage to the casing. The end result was a system
that could strip a booster in a fraction of the time required
by manual methods.
This technological solution and its subsequent commercialization
is a prime example of high value spinoff from aerospace technology
(in this case NASA and, later, Department of Defense technology).
It is an example of a technology transfer that not only resulted
in formation of a new company, but also spawned a whole new industry.
The innovative technology offers a broad range of benefits to
maintenance and overhaul organizations in cost and time savings,
worker protection and a variety of environmental protection advantages.
United Technologies Corporation took advantage of the apparent
commercial potential of the system by investing company funds
in refining the NASA/USBI technology, advancing it in new directions,
and-in January 1993-establishing a company to commercialize and
market the technology. The company is Waterjet Systems, Inc.,
Huntsville, Alabama, operated by United Technologies' Pratt &
Whitney division. Waterjet Systems pursued the military potential
of the technology under an Air Force MANTECH (manufacturing technology
transfer) program to adapt the booster-stripping technology to
large aircraft, then extended the technology to ships through
a Navy MANTECH program.
With these and other extensions of the technology, Waterjet
Systems established a family of hydroblast systems under the
general designation ARMS® (Automated Robotic Maintenance
Systems). Generally, they employ high pressure water pumps to
create waterblast streams at 55,000 pounds per square inch that
are controlled by target sensitive robots maneuvering precisely
over one-of-a-kind surfaces. The ARMS family includes:
Aircraft ARMS®. The first application of Aircraft
ARMS, a fully automated version derived from the NASA/USBI technology
and refined under the Air Force MANTECH program, is the LARPS
(Large Aircraft Robotic Paint Stripping) system for Air Force
use. Introduced to operational service in 1995, its goals are
to reduce stripping time by 50 percent and use of hazardous chemicals
by 90 percent. Aircraft ARMS systems are designed for painting
and depainting commercial as well as military aircraft.
The decoating system can reach high surfaces, eliminating
the need for scaffolding.
Ship ARMS®. The Ship ARMS Decoating System was
designed for use on large ships, boats, barges, floating drydocks
and other vessels. It is a semiautomated, totally mobile system
that includes a trailer-based high pressure high flow water pump,
a precision computer-designed nozzle and a specialized robotic
manipulator and end effector. The system not only strips a ship's
multilayer anticorrosion and antifoulant coatings, one layer
at a time, but also captures all process effluent; a specially
designed vacuum shroud and water recovery/reuse system collects
stripped materials and prevents hazardous materials from running
off into the water or onto the dock. The U.S. Navy was the first
customer; the process has been demonstrated on the aircraft carrier
USS Nimitz and two other ships. Among a lengthy list of benefits
are environmental gains, such as no airborne particles, reduced
waste disposal, reduced eco-impact, and cost-related gains, such
as no need for scaffolding or masking, shorter strip and drydock
time, and less cleanup.
Engine ARMS®. Turbine engine parts-vanes, combustors,
blades, for example-have a variety of coatings to protect them
from the hot operating environment. At overhaul time, the engine
is disassembled and the parts are stripped of their coatings,
customarily by acid bath and grit blasting, processes that are
both labor intensive and hazardous to personnel. Engine ARMS
does the job faster and cheaper with bonuses in reduction of
toxic chemicals, waste disposal and human protection equipment.
Component ARMS®. Components in this sense means
major segments of aircraft or military/industrial systems. Among
examples that can be decoated by Component ARMS are engine cowlings,
rudders, flaps, radomes, helicopter blades, horizontal stabilizers,
tail cones and small vehicles (Humvees, armored personnel carriers,
tanks, etc.).
®ARMS, Aircraft ARMS, Engine ARMS, Ship
ARMS and Component ARMS are registered trademarks of United Technologies
Corporation.
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