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An Overview
Selective Laser Sintering (SLS) builds a part in layers by sintering a heat-fusible powder with a laser beam. The part is built upon a platform that is placed just below the surface of the powder. The laser beam sinters the powder by heating the powder just above the melting point which cools to a solid once the laser beam passes. The laser beam is directed toward the platform in such a manner that the first cross-sectional slice of the part is first sintered. The platform is then lowered the depth of one layer and the next cross-sectional slice is sintered. This process is repeated until all of the layers of the part have been sintered. Once the part is entirely built, the platform is raised above the surface of the powder and any excess powder is brushed away. Any manual finishing can then be performed.
Some powders that can be used for this technology include polymers (nylon and polystyrene), metals (steel, titanium, alloy mixtures, and composites) and green sand. Some examples of powders for specific types of parts include nylons and glass filled nylons for functional parts; and polystyrene for investment castings applications.
Parts built using this technology are porous and depending on the application may require some finishing consisting of filling any voids with another material and/or applying a painted finish.
The strength, details, and quality of these parts tend to be very good although some fine details and sharp edges can loose some definition. Large numbers of parts can also be built on a platform at the same time increasing productivity. This technology is known for the ability to handle complex part geometries and is used for limited production runs. Supports are also generally not required when building parts using this technology.
This technology was developed in the 1980s and patented in 1989 by Dr. Carl Deckard at the University of Texas at Austin. Dr. Deckard developed this technology for his mater's thesis and is considered to have been instrumental in contributing to the initiation of Rapid Prototyping.
Disclaimer
DPT may not provide some of the services and/or techniques presented in the Knowledge Center. For a full list of services we do offer, please visit our rapid prototyping page.
