Originally developed at the University of Texas and commercialized
by DTM Corporation (now 3D Systems), the SLS rapid prototyping process
uses the heat of a CO2 laser to “sinter”
or melt powdered thermoplastic materials (or thermoplastic binders
in high temperature resistant powdered materials such as ceramics
and metals) in layers of .003” to .006”.
The laser is guided across the part bed by a scanning system
and “selectively” sinters or melts the material based
on cross-sectional slice information of the 3D CAD data file. The part or parts are built in an atmosphere
that controls the thermal distribution and thus requires very little
laser power to sinter the material.
The powder in the build chamber acts as a support for the
part during fabrication and thus no additional support structure
is required. SLS is able to produce parts with tolerances
and detail similar to SLA, but with the added advantage of strength.
Although new SLA rapid prototyping resins have proven to
be stronger than in the past, they do not have the durability and
long-term stability of SLS rapid prototype and rapid production
thermoplastics that do not lose shape, post-cure and/or become brittle
The primary benefit of the SLS rapid prototyping process
is the durability of the materials.
The SLS process has arguably the widest range of engineering-grade
rapid prototyping materials available in the rapid prototyping industry. These include the nylon-based DuraForm™
and DuraForm GF™ for functional plastic rapid prototypes,
CastForm™ for rapid prototype investment casting patterns,
Somos 201 and FR85A for rubber-like rapid prototypes and LaserForm™
A6/bronze for metal rapid prototypes.
With the exception of the LaserForm metal material, the SLS
rapid prototyping materials also do not require any post-curing
and are ready for use after minimal clean up and finishing.
There are other materials currently in development that will
not only be valuable for rapid prototyping applications but also
for end-use production applications.
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