The filament of the 3D printer allows the fused deposition modeling 3D printers to work. This kind of 3D printer works by melting the filament through a heated nozzle and extruding it to build up something three-dimensional, layer by layer. Filaments come in different diameters but are usually 1.75 mm or 2.85 mm; they are also available in different materials, colors, and properties and, hence, intended applications and finishes.