<P> Fused filament fabrication (FFF) is a 3D printing process that uses a continuous filament of a thermoplastic material . This is fed from a large coil, through a moving, heated printer extruder head . Molten material is forced out of the print head's nozzle and is deposited on the growing workpiece . The head is moved, under computer control, to define the printed shape . Usually the head moves in layers, moving in two dimensions to deposit one horizontal plane at a time, before moving slightly upwards to begin a new slice . The speed of the extruder head may also be controlled, to stop and start deposition and form an interrupted plane without stringing or dribbling between sections . Fused filament fabrication was coined by the members of the RepRap project to give a phrase that would be legally unconstrained in its use, given patents covering fused deposition modeling (FDM). </P> <P> Fused filament printing is now the most popular process (by number of machines) for hobbyist - grade 3D printing . As other techniques, such as photopolymerisation and powder sintering, may offer better results at greater cost, they still dominate commercial printing . </P> <P> The 3D printer head or 3D printer extruder is a part in material extrusion - type printing responsible for raw material melting and forming it into a continuous profile . A wide variety of materials are extruded, including thermoplastics such as acrylonitrile butadiene styrene (ABS), polylactic acid (PLA), high - impact polystyrene (HIPS), thermoplastic polyurethane (TPU), aliphatic polyamides (nylon), and recently also PEEK . Paste - like materials such as ceramics and chocolate can be extruded using the fused filament process and a paste extruder . </P> <P> Additive manufacturing (AM), also referred to as 3D printing involves manufacturing a part by depositing material layer by layer . There is a wide array of different AM technologies that can make a part layer by layer, including material extrusion, binder jetting, material jetting and directed energy deposition . </P>

What is the extruder in a 3d printer