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Silicon mold for small production
Introduction to Rapid Prototyping
SLA(Stereolithography)
RIM
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we use 3D Systems
SLA
® machines for
rapid
prototyping and pattern making for
use with secondary molding or casting processes.
Stereolithography is an additive
manufacturing process which employs a vat of
liquid ultraviolet curable photopolymer "resin"
and an ultraviolet laser to build parts' layers
one at a time. For each layer, the laser beam
traces a cross-section of the part pattern on
the surface of the liquid resin. Exposure to the
ultraviolet laser light cures and solidifies the
pattern traced on the resin and joins it to the
layer below.
After the pattern has been traced, the SLA's
elevator platform descends by a distance equal
to the thickness of a single layer, typically
0.05 mm to 0.15 mm (0.002" to 0.006"). Then, a
resin-filled blade sweeps across the cross
section of the part, re-coating it with fresh
material. On this new liquid surface, the
subsequent layer pattern is traced, joining the
previous layer. A complete 3-D part is formed by
this process. After being built, parts are
immersed in a chemical bath in order to be
cleaned of excess resin and are subsequently
cured in an ultraviolet oven.
Stereolithography requires the use of supporting
structures which serve to attach the part to the
elevator platform, prevent deflection due to
gravity and hold the cross sections in place so
that they resist lateral pressure from the
re-coater blade. Supports are generated
automatically during the preparation of 3D
Computer Aided Design models for use on the
stereolithography machine, although they may be
manipulated manually. Supports must be removed
from the finished product manually, unlike in
other, less costly, rapid prototyping
technologies.
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