Rapid
Prototyping -- Electron
Beam Melting - EBM
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Metal
Part made by
Arcam's EBM Process
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With Arcam's Electron
Beam Melting method a 100% solid metallic
object is produced directly from metal
powder. The part, which is to be produced,
is designed in a three-dimensional CAD
program. The model is sliced into thin
layers, approximately a tenth of a millimeter
thick. From a magazine of powder, an
equally thin layer of powder is scraped
onto a vertically adjustable surface.
The first layers geometry is then
created through the layer of powder
melting together at those points directed
from the CAD file, with a computer controlled
electron beam. Thereafter, the building
surface is lowered just as much as the
layer of powder is thick, and the next
layer of powder is placed on top of
the previous. The procedure is then
repeated so that the object from the
CAD model is shaped, layer by layer
by layer, until a finished metal part
is complete.
The usage of a highly
efficient computer controlled electron
beam in vacuum provides high precision
and quality. EBM makes possible the
fabrication of homogeneous metal components
such as complex tooling for spray-forming
and injection molding tools and functional
prototypes in a very short time. The
production process is fast in comparison
with conventional manufacturing methods.
The highly efficient system produces
parts from titanium powder and does
so between three and five times faster
than other additive fabrication methods.
One other advantage is that reworking
of the part is minimized. In contrast
to laser sintering (SLS), the electron
beam fully melts the metal particles
to produce a void-free part. The process
occurs in a high vacuum, which ensures
the part is completely solid, without
imperfections caused by oxidation.
The EBM process is ideal
for applications where high strength
or high temperatures are required. The
machine creates parts comparable to
wrought titanium and better than cast
titanium, with a 95 percent powder recovery
yield. Medical product manufacturers
can benefit from the parts' high flexural
strength for bone implants requiring
cycle life exceeding 10 million cycles
(or movements). Automobile makers can
build strong parts for high temperature
testing, including under-the-hood applications.
Aerospace engineers will be interested
in the combination of a high strength
yet light weight titanium part. And
because the EBM process produces a homogenous
solid, parts can be flight-certified.
The process uses a
high power electron beam that is 95
percent efficient -- 5 to 10 times more
so than a laser beam. This efficiency
results in the creation of parts 3 to
5 times faster than other metal additive-fabrication
methods, and it uses only seven kW of
average power. With laser-based systems,
like sintering, 95 percent of the light
energy is reflected by the powder rather
than absorbed, significantly reducing
efficiency.
Two variations of titanium
"six four" alloy are available
for the EBM S400: Ti6AL4V and Ti6AL4V
ELI. Titanium parts created on the system
are accurate near-net shape and are
HIP heat treatable. The system builds
parts up to approximately 8 x 8 x 7
in. (200 x 200 x 180 mm), with a layer
thickness range of 0.002 to 0.008 in.
(0.05 - 0.2 mm).
EBM systems are manufactured
by Arcam AB and distributed in North
America by Stratasys. Outside North
America, the system is available from
Arcam as the EBM S12.