SLS technology uses a laser to harden and bond small grains of nylon and elastomer materials into layers in a 3D dimensional structure. The laser traces the pattern of each cross section of the 3D design onto a bed of powder. After one layer is built, the bed lowers and another layer is built on top of the existing layers. The bed then continues to lower until every layer is built and the part is complete. One of the major benefits of SLS is that it doesn’t require the support structures that many other 3D printing technologies use to prevent the design from collapsing during production.

Stereolithography is a laser-based technology that uses a liquid photopolymer resin cured by an UV. A UV laser beam scans the surface of the resin and selectively hardens the material corresponding to a cross section of the product, building the solid model from supplied 3D data. SLA has many common characteristics with Direct Light Processing (DLP), another photopolymerization 3D printing technology. For simplicity, the two technologies can be treated as equals. The SLA process addresses the widest range of rapid manufacturing applications. The required supports for overhangs and cavities are automatically generated, and later manually removed.

Fused Deposition Modeling is an additive manufacturing process that belongs to the material extrusion family. In FDM, an object is built by selectively depositing melted material in a pre-determined path layer-by-layer. The materials used are thermoplastic polymers and come in a filament form. FDM is the most widely used 3D printing technology: it represents the largest installed base of 3D printers globally and is often the first technology people are exposed to. In this article, the basic principles and the key aspects of the technology are presented.