Selective laser sintering
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Selective laser sintering (SLS) is an additive rapid manufacturing technique that involves using a high power laser (for example, a carbon dioxide laser) to fuse together small particles of plastic, metal, or ceramic powders into a mass respresenting a desired 3 dimensional object. The laser selectively fuses powdered material by scanning cross-sections generated from a 3D digital description of the part (e.g. from a CAD file or scan data) on the surface of a powder bed. After each cross-section is scanned, the powder bed is lowered by one layer thickness, a new layer of material is applied on top and the process is repeated until the part is completed.
Compared to other methods a relatively wide range of powder materials can be processed. Commercially available materials include polymers (nylon, also glass-filled or with other fillers, and polystyrene), metals (steel, titanium, alloy mixtures and composites) and foundry sand. The physical process can be full melting, partial melting, liquid-phase sintering, etc., and depending on the material up to 100% density can be achieved and material properties comparable to those from conventional manufacturing methods. In many cases large numbers of parts can be packed within the powder bed, allowing a very high productivity.
SLS was invented originally by R.F. Housholder who patented the concept in 1981 but did not commercialize it. A variation was developed at the University of Texas in the mid-1980s and was licensed to an Austin, Texas Company (DTM Corporation) that commercialized the technology. The process is carried out in machines called Sinterstations and is in wide use around the world initially for building prototypes of parts early in the design cycle of articles. The technology is now moving into limited run manufacturing, taking advantage of its ability to easily make very complex geometries directly from digital CAD data. In 2001 3D Systems, Inc. in Valencia, California acquired DTM Corporation and now manufactures and sells Sinterstations.
External links
SLS providers
- Rapid Prototyping, Stereolithography, Selective Laser Sintering (http://www.paramountind.com) at Paramount Industries
- Rapid Prototyping, Rapid Tooling, Selective Laser Sintering (http://www.protocam.com) at ProtoCAM