The blades were previously machined, leaving a lot of
waste. The nozzles required assembly of several pieces,
which now can be made from a unitized structure.
Northrop Grumman used titanium and the electron
beam-melting process to fabricate hot air mixers for
About 100 parts on an F/A- 18 are made from AM,
Ducting and piping are good candidates for AM.
“A single piece can be optimized for system performance as opposed to post-production assembly, avoids the
joints and seams that can restrict flow, and reduces extra
material and weight required to weld, bolt or screw parts
together,” Cheney-Peters said.
Shinbara’s presentation in June at the American Society
of Naval Engineers’ Hi-Per (High Performance) Craft con-
ference in Norfolk, Va., noted that, “if you haven’t heard
about AM, you should get smart about it, and if you have
heard about it, there’s been great progress for applications,
such as the small boat industry, and there was quite a bit
of interest in the combat craft community.”
AM is not just for fabrication. For maintenance and
repair, AM can be used to restore shape to damaged
parts by adding material to fractures or jagged edges.
“Most parts are made of standard materials, such as
stainless steel, titanium or copper, so it’s relatively easy
to have those materials available for repair. To repair a
crack or replace missing material, you can use a hopper or reel material feed process — much like a glue
gun — to only add material where you need it,”
The Army’s Mobile Parts Hospital in Southwest Asia
is a shipping container that will be equipped as an AM
repair shop. With the proper parts library, new parts can
be fabricated. If the digital file for a part is not available,
the part can be scanned and a new file created.
“3D models aren’t always available. Sometimes, all
you have are 2D drawings,” Shinbara said. “But that’s
OK, because 3D files can be generated.”
3D printing is actually a succession of 2D slices,
with layers added upon each other.
“When added together, they become your 3D contour,” Shinbara said.
Most new or refurbished parts still cannot come out
of the printer ready to be installed. A new part still may
need to be heat treated to give it the right metallurgical
properties, and surface finishing may still be required.
Shinbara said the future of AM is bright.
“There will be a vast increase in number of qualified
materials you can use. Simulation can be used for ‘
virtual testing,’ instead of waiting until the part is done to
see if it works. You don’t lose a build if you get laser
drift or have thermal inconsistencies. You can make
Invitation to Innovate
The Chief of Naval Operations’ Rapid Innovation Cell
(CRIC), managed by Navy Warfare Development
Command (NWDC), is aimed at giving junior leaders
the chance to identify, work with and rapidly field
emerging and disruptive technologies — such as AM
— that address the Navy’s most pressing challenges.
“We are looking for innovation-minded personnel
with a demonstrated ability to think and operate out-
side normal paradigms,” said Rear Adm. Terry B. Kraft,
NWDC commander. “The CRIC was established to
give our junior ‘disruptive thinkers’ a safe haven to
mature nontraditional solutions until they can effec-
tively demonstrate their value to the fleet.”
If complexity — usually one of the biggest cost drivers
— is not a factor in the manufacturing business case for
AM, speed and quantity certainly come into play. Efficient
manufacturing relies on making quality parts in econom-
ical quantities at high speeds. AM cannot do that. Imagine
printing tens of thousands of copies of the Washington
Post with a laser printer instead of high-speed presses.
The ease by which things can be copied also raises
numerous questions about intellectual property.
“Down the road, we can expect more materials, larger
volumes, better predictability, easier certification and
faster printing times at higher resolution,” said Lawrence
C. Schuette, acting director of research at the Office of
Naval Research. “With time, we’ll see tightly controlled
blending of materials. To fully capitalize on the advan-
tages of carbon fiber, we’ll grow structures instead of glu-
ing or bolting them together from different parts.”
“People think of the replicator on ‘Star Trek,’” said
Wolk. “AM has that potential, but we’re not there yet.” n
An X-47B Unmanned Combat Air System demonstrator
completes an arrested landing on the flight deck of the
aircraft carrier USS George H.W. Bush July 10 in the Atlantic Ocean. To create an urgently required tailhook point
for the aircraft, Fleet Readiness Center Southwest used
a Stereo Lithography Apparatus to generate a plastic
copy of the part so it could be shipped to Patuxent River,
Md., for a fit check on an X-47B. Then the actual part
could be machined from heat-treated, high-strength steel
for use on the aircraft.