Selective Laser Sintering
OverviewDeveloped by Carl Deckard for his master’s thesis at the University of Texas, selective laser sintering was patented in 1989. The technique, shown in Figure 3, uses a laser beam to selectively fuse powdered materials, such as nylon, elastomer, and metal, into a solid object. Parts are built upon a platform which sits just below the surface in a bin of the heat-fusable powder. A laser traces the pattern of the first layer, sintering it together. The platform is lowered by the height of the next layer and powder is reapplied. This process continues until the part is complete. Excess powder in each layer helps to support the part during the build. SLS machines are produced by DTM of Austin, TX.
The SLS
technology uses a CO2 laser to sinter (fuse) a variety of thermoplastic
and metal powders to "grow" 3D objects layer-by-layer from 3D
electronic data (STL
This file format used in industry to define the geometry of the part to be made. STL files are created by CAD programs by translating their native or neutral files into the STL format. The STL file defines the coordinates of numerous triangular facets that approximate the shape of an object or part. This is the standard file format for all rapid prototyping processes. The extension stands for StereoLithography but the format applies to all major rapid prototyping technologies.'); return false">STL files). Because this is an additive process,
highly complex geometries can be built without issue, and because the
powder holds the parts, no support structures have to be added and
removed. The key advantage of SLS is its ability to rapidly produce
durable, functional objects for a wide variety of applications.
• Working parts and assemblies with good detail and surface finishing
• Variety of materials: rigid and flexible plastics, fully dense metal, rubber-like elastomer, foundry-friendly patterns
• Capable of living hinges, high-flex snaps, high stress and heat tolerance and service as short-run tooling
• Can be finished and painted for presentation, demonstration and video reproduction
• Dimensional tolerancing within thousandths of an inch
• Delivery of most parts and patterns in just a few working days
Figure
3: Schematic diagram of selective laser sintering.
