Selective Laser Sintering (SLS) technology uses laser beam as the heat source for melting of polymer powder, mainly different mixtures with the polyamide PA 12 as the primary component. The laser usually operates in near infrared range (with wavelength up to 10 μm), and the laser beam motion, which exposes selected areas of the powder bed to heating, as controlled by an optical system containing of mirrors and lenses.

Apart from the other properties of PBF technologies for polymer materials, the SLS technology has also the following properties:

• The concentration of the absorbed heat in the focus of the laser beam allows the SLS technology to be used for processing of wider set of materials then it is the case with MJF technology;
• The refreshment rate (the required ratio between the virgin powder and total mass of production powder mixture) is at least 50%, which is higher (and worse) than in it is the case with MJF technology; despite this, the material costs of the SLS technologies are not higher than those of MJF technology, because SLS technology does not require use of other materials besides the production powder.