English: Schematic representation of the 3D printing technique known as Fused Filament Fabrication; a filament a) of plastic material is feeded through a heated moving head b) that melts and extrudes it depositing it, layer after layer, in the desired shape c). A moving platform e) lowers after each layer is deposited. For this kind of technology additional vertical support structures d) are needed to sustain overhanging parts.