Selective Laser Sintering (SLS) is a rapid prototyping process that uses bonded
powdered material to form models, prototypes, and patterns [Marcus et al, 1990 a and b;
Manthiram et al, 1993]. Within SLS, a compartment contains a laser and the platform
upon which the model is built. The compartment walls consist of infrared heat panels,
which act to heat the powdered material to just below the material’s melting point. The
workspace consists of a platform that lowers the model as each successive layer is
added. A powder cartridge supplies the powdered material used to produce the part, and
a roller is used to distribute the material evenly across the workspace (Figure 2.7).
The SLS process begins with a thin layer of powdered material spread evenly across the
workspace. The laser traces the pattern of the slice on the layer of powdered material,
heating and fusing the material it comes in contact with. Only the material in the laser’s
path is sintered; careful modulation of the laser beam intensity assures that the
surrounding powdered material remains unaffected. The movable platform lowers the
workpiece to allow for the construction of the next layer. After one layer of the
component is formed, the area is prepared for the next slice of CAD data as another
layer of powdered material is deposited on the workspace and distributed by the roller.