Selective laser sintering (SLS) is used to build your design with nylon 12. The models are printed layer by layer by a laser that draws thin lines in the powder, which melts and bonds it together in order to form a thin layer of the model. After a layer is printed, a new layer of fresh powder is spread over the surface by a roller. The printer has a print chamber that is heated to just below the melting point of the powder; the laser beam adds the extra energy to melt the powder, forming a solid model.