The traditional “subtractive” method of creating a part begins with a big piece of solid material, or “billet,” that you then “machine out.” Casting
and machining parts results in a significant amount of
waste. In contrast, additive manufacturing, or AM, creates
parts layer by layer, with a design based on a 3D model in
a computer, and builds it up. There is little waste.
Jennifer Wolk, a materials engineer at Naval Surface
Warfare Center Carderock Division (NSWCCD),
Bethesda, Md., said AM technology is not new.
“We’ve been following this technology for a long
time,” she said.
A number of commands are using and researching
AM, including Naval Warfare Development Command,
the Navy’s air, surface and undersea warfare centers, the
Space and Naval Warfare Systems Command, and others.
“There’s a lot of collaboration,” Wolk said. “We’re all
trying to make the technology more accessible for the
warfighter. When people think of manufacturing, they
think of the old paradigm. Today, there is a much larger
skill set involved.”
AM is not just for finished items. It is a communica-
tions and discovery tool, a way of explaining some-
thing. If a picture is worth a thousand words, then an
object that you can see and feel is worth even more.
Patterns and molds can be made for urethane or sand
castings. A test article can be created and evaluated and,
Just as printing a document by
creating very thin layers of differ-
ent colors of ink onto paper, a
process called material jetting can
create shapes with successive lay-
ers of material on an object.
Instead of ink, 3D printing uses
polymers or metals. Material jetting is one of many processes and
methods that come under the overarching category of AM, commonly
known as 3D printing or rapid prototyping.
Fused deposition modeling (FDM) involves super-thin layers of production-grade thermoplastic material.
Computer-aided design (CAD) files are sent to the 3D
printer the same way the print driver software works,
telling the 3D print head where to deposit both plastic
and soluble support material.
For intricate parts, the support material can keep
the plastic components apart and be dissolved after the
part is completed. Think “ship in a bottle.” AM can
even be used for parts with inner mechanisms.
There are a limited number of materials that are
suitable for AM. As a rule of thumb, any material that
can be welded can be used for AM. As with welding,
the melting and high temperatures involved with the
different layers must be precisely controlled to make
sure it has the right properties.
To create an urgently required tailhook point for the
Navy’s X-47B Unmanned Combat Air System, so the
test program for the experimental unmanned fixed-winged carrier-based aircraft could remain on schedule, Fleet Readiness Center Southwest (FRCSW) 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 aircraft. Then,
the actual part could be machined from heat-treated,
high-strength steel for use on the aircraft.
The Promise of
Additive manufacturing technology can
shave time, cost from naval applications
By EDWARD LUNDQUIST, Special Correspondent
3D objects can be made by building up many 2D layers.
n Additive manufacturing (AM) can create parts with inner mechanisms and embedded electronics.
n Cost is not driven by complexity.
n Being able to create objects with the click of a mouse may
seem too good to be true, but AM technology is a reality today.