Abstract: An extruder for additive manufacturing extends about, and along, a longitudinal axis and has an extrusion nozzle having a polygonal cross-section and a mounting member provided with: a ring configured to be mounted to a bearing coaxial to the extruder and allowing the rotation of the mounting member about the longitudinal axis; a hollow body arranged within the ring and configured to house, in part, an extrusion screw; and a plurality of spokes for connecting the hollow body to the ring so as to define compartments between the spokes-adjacent the hollow body and the ring.

Abstract: The invention relates to a method and an apparatus for the three-dimensional printing of articles made of thermoplastic polymeric material. The method comprises the steps of: providing an extrusion head equipped with a nozzle having a dispensing opening; feeding the extrusion head with a thermoplastic polymeric material; melting the thermoplastic polymer material in the extrusion head; moving the extrusion head along at least three axes in accordance with a predefined three-dimensional model; and dispensing, during step d), the molten thermoplastic polymeric material through the dispensing opening of the nozzle, depositing it according to superimposed layers on a printing plane or surface to form a moulded article.