Selective Laser Sintering Selective laser sintering is an additive rapid prototyping technique that uses a high power laser to fuse small particles of thermoplastic, metal, polyamide (nylon), ceramic, or glass filled nylon. SLS offers the key advantage of making functional parts in essentially final materials, depending on use of the part. Brian Reniker

SLS prototypes like many rapid prototyping processes are constructed from a .STL file. A .STL file is is simply a mesh of triangles wrapped around a CAD model (this was defined by 3D CAD systems in 1980s). .STL’s name is derived from a rapid prototyping process, StereoLithography, also known as abbreviation of Standard Triangulation Language. This very simple format has become an industry standard for the Rapid Prototyping sector. The Solid Models as a: (a) Solid Model, (b) an STL file, and (c) in Sliced Layers.

A thermoplastic is a plastic that melts to a liquid when heated and freezes to a brittle, very glassy state when cooled sufficiently. The process of Selective Laser Sintering (SLS) is somewhat similar to sterolithography, in that a prototype is produced rapidly through layering of material. From thermoplastic powders mostly, although SLS is useful in that many different materials can be used.

Such as, polyamide (Nylon), material allows the production of fully functional prototypes with high strength. Glass Filled Nylon is suitable for high thermal resistance and high impact strength prototypes. SLS Somos 201 is used for functional rubber like parts. Depending on the use of the part being constructed these parts may be functional, a capability which is exceptionally useful.

Price - Multiple pieces of the same part are much cheaper than ordering a single piece. Even various SLS models ordered at the same time as a single batch are much cheaper to make than ordering separately. Speed - It could be few hours or a day it really depends upon the build size, shape, and accuracy needed.

Size of SLS single-made parts are generally 13. 3” x 13. 3” x 2’ Size of SLS single-made parts are generally 13.3” x 13.3” x 2’. Although larger parts can be constructed by making many smaller parts to assemble, and form a larger part. The thickness of an individual SLS layer is 0.15 to 0.2 mm layer thickness, depending upon the material used.

The process of Selective Laser Sintering is actually quite simple The process of Selective Laser Sintering is actually quite simple. The entire internal system is heated to below the melting point of whatever substance is being used. So that when heat is applied by the high energy CO2 laser melts and fuses (sinters) the substance. To do this two piston-like platforms, a roller, an optical sensor, and whatever material is being used to form a part are used in co-ordination with the laser.

The first piston contains most of the substance The first piston contains most of the substance. When this piston is raised it makes the substance available to the roller. The roller moves the material over the second piston to cover the part being constructed. The material which has been moved to the second piston will then be sintered by the laser, to form an additional layer on the part.

Bibliography http://www.conceptual-reality.com/sls.htm http://home.att.net/~castleisland/sls_int.htm http://www.arptech.com.au/slshelp.htm http://www.me.utexas.edu/~rbarr/rapid/Types_Of_RPS.html http://www.3drg.com/our_process.php