Figure 1.

Examples of additive manufacturing (AM) systems that use polymer materials: (a) Material jetting, where a photo-sensitive photopolymer is deposited in droplets that are then polymerized by a passing light source. The process is repeated so that the solid object is built up layer by layer on the build tray. (b) Vat polymerization, where a photosensitive polymer contained in a vat is polymerized in a layer-by-layer fashion either by a light-beam (stereolithography and multi-photon polymerization) or by light-projection (digital light processing ). (c) Material extrusion, where the polymer filament is softened as it passes through a heating block and extruded in a layer-by-layer fashion.