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STEREOLITHOGRAPHY
Spectrum 3D's specialized stereolithography (SLA) services focus
on the needs of Mechanical Engineers and Industrial Designers. For
years we have met and exceeded their deadlines and quality expectations.
Our attention to detail serves our clients well. Being only partial
reliant on automated equipment during the clean up stages, coupled
with extensive continuous SLA experience, sets us apart. Spectrum
3D's total quality equation provides excellent cosmetic and dimensional
results.
Video courtesy of 3D Systems
Stereolithography (SLA) is often considered the pioneer of the
Rapid Prototyping industry. The first commercial system was introduced
in 1988 by 3D Systems. The SLA system consists of a ultra-violet
laser, a vat of photo-curable liquid resin, a perforated platform
immerged in the vat, and a controlling system.
A platform is lowered into the resin such that the surface of the
platform is a layer-thickness below the surface of the resin. The
laser beam then traces the boundaries and fills in a two-dimensional
cross section of the model, solidifying the resin wherever it touches.
Once a layer is complete, the platform descends a layer thickness,
resin flows over the first layer, and the next layer is built. This
process continues until the model is complete.
Once the model is complete, the platform rises out of the vat and
the excess resin is drained. The model is then removed from the
platform, washed of excess resin, and then placed in a UV oven for
a final curing. The model then undergoes a cleanup process in order
to achieve the desired finish.
SLA MATERIALS
SI-50: A durable, accurate SL material that simulates
molded ABS, and is equally well suited for functional prototypes
and master patterns.
SI-40: The first SL material to combine high temperature
resistance with toughness.
SI-45HC: Perfect for small parts with fine detail.
Photo courtesy of 3D Systems |
SLA LEAD TIMES
Spectrum 3D's SLA lead times are normally between 2-3 days. Larger
projects may require more time, but seldom over 7 business days. Expedite
services are available upon request.
BUILD POSITION OPTIONS
Vertical build - This is used for parts that have geometrical attributes
which will be represented by the SLA more efficiently due to the
absence of "stair stepping" on a complex or finely detailed
surface. The wavy surfaces will face tangent to the build platform.
Build layer thickness - Spectrum 3D's choice of Ciba SL 5170 photopolymer
permits a layer thickness variation of .002 - .006 in. Thinner layer
thickness allows for the successful build of tiny parts or geometrical
attributes without "stair stepping". This process eliminates
clean up and the possibility of distortion or damage caused by abrasives.
FINISHING OPTIONS
All of our SLA work always meets a high level of quality. Our clients
are offered the option of "mold ready" or finely detailed
cleanup of their parts at a reasonable cost. This is specifically
indicated for SLA parts that are not quoted for molds and castings.
A "mold ready" cleanup is included in the mold quote.
Level 1 - This is the most economical finish.
The supports are removed and the parts are cured with minimal finish.
Level 2 - The Level 1 finishing is included. After
curing and support removal, parts are sanded lightly and bead blasted
for an accurate finish. Included is the removal of the build lines
and support structures, and treating the part with light abrasives.
Level 3 - All of the previous finishing levels
are included. Parts are more thoroughly sanded and then coated with
primer.
Level 4 - Parts are sanded and primered plus painted
to customer color, for a fully painted and "trade show"
quality finish of the exterior surfaces. Painted parts are quoted
assuming a textured surface. The paint may be color matched for
a $100 fee.
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