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Selective Laser Sintering (SLS, a registered trademark of 3D Systems, Inc.^[1]) is an additive rapid manufacturing technique that uses a high power laser (for example, a carbon dioxide laser) to fuse small particles of plastic, metal, or ceramic powders into a mass representing a desired 3-dimensional object. The laser selectively fuses powdered material by scanning cross-sections generated from a 3-D 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 rapid manufacturing methods, SLS can produce parts from a relatively wide range of commercially available powder materials, including polymers (nylon, also glass-filled or with other fillers, and polystyrene), metals (steel, titanium, alloy mixtures, and composites) and green sand. The physical process can be full melting, partial melting, or liquid-phase sintering. And, depending on the material, up to 100% density can be achieved with material properties comparable to those from conventional manufacturing methods. In many cases large numbers of parts can be packed within the powder bed, allowing very high productivity.

SLS is performed by machines called SLS systems; the most widely known model of which is the Sinterstation SLS system. SLS technology is in wide use around the world due to its ability to easily make very complex geometries directly from digital CAD data. While it began as a way to build prototype parts early in the design cycle, it is increasingly being used in limited run manufacturing to produce end-use parts.

A process similar to SLS was invented by R.F. Housholder who patented the concept in 1979 but did not commercialize it. SLS itself was developed and patented by Dr. Carl Deckard at the University of Texas at Austin in the mid-1980s and was licensed to DTM Corporation of Austin, Texas. In 2001, 3D Systems, Inc. of Valencia, California acquired DTM Corporation and now manufactures and sells SLS systems and SLS powder materials worldwide.^[2]

Another manufacturer of selective laser sintering equipment is EOS GmbH of Munich, Germany.^[3] EOS (The acronym stands for "Electro Optical Systems") started as manufacturer of Stereolithography systems, and later expanded their portfolio to include laser sintering systems. The stereolithography business was subsequently sold, and EOS is now exclusively manufacturing laser sintering systems in variants for sintering Polymers (EOSINT P), Metal (EOSINT M) and Sand (EOSINT S, for foundry applications).

1. ^ http://www.3dsystems.com
2. ^ http://www.3dsystems.com
3. ^ http://www.eos-gmbh.de

• The Rapid Prototyping Home Page
• Castle Island's Worldwide Guide to Rapid Prototyping
• Comparison chart of rapid prototyping technologies at XPress3D.com
• Rapid prototyping provider specializing in selective laser sintering - Paramount PDS
• SLS prototype technology overiew, advantages, and materials - ProtoCAM