RepRap



The RepRap project is a British initiative to develop a 3D printer that can print most of its own components. RepRap (short for replicating rapid prototyper) uses an additive manufacturing technique called fused filament fabrication (FFF) to lay down material in layers; a plastic filament or metal wire is unwound from a coil and supplies material to produce a part. The project calls it fused filament fabrication to avoid trademark issues around the "fused deposition modeling" term. As an open design, all of the designs produced by the project are released under a free software license, the GNU General Public License.

Source: Wikipedia