Extrusion device and 3d printer

A three-dimensional (“3D”) printer, comprising:

• an extrusion device including:
• first means for feeding reinforcing filaments;
• second means for feeding an at least partially molten thermoplastic material;
• at least one impregnation chamber for impregnating reinforcing filaments with said thermoplastic material so as to provide an impregnated multifilament, said impregnation chamber extending around an axis;
• at least one device body that defines:
• (a) first openings for transit of the reinforcing filaments from the first feeding means to the impregnation chamber;
• and (b) at least one second opening for transit of the thermoplastic material from the second feeding means to the impregnation chamber;
• at least one dispensing nozzle for dispensing the impregnated multifilament;
• and
• at least one twisting member arranged fluidically upstream of and rotatably with respect to the dispensing nozzle so as to produce a vortex movement of the thermoplastic material inside said impregnation chamber and, therefore, said vortex cause twisting of the reinforcing filaments.