A 3D printer prints parts by adding material, layer-by-layer. Unlike other CNC machining techniques that are subtractive (they remove material from a workpiece block), 3D printers are a form of additive manufacturing. But, they are still CNC machines.
There are many methods of 3D printing: fused deposition modeling, stereolithography, selective laser sintering, multijet fusion, and more. But at the hobby level, the most common types of 3D printers use FDM (fused deposition modeling), or LCD, which is a form of resin printing.
FDM 3D printers use a filament, which is a coil of long and narrow string of thermoplastic. They have a nozzle that’s heated at the end (called the hot-end). This heat melts the filament, just like a glue gun, and then the extrusion system feeds this filament thorough the nozzle and deposits it on the print bed.
