A print head for a 3D printer includes a nozzle for dispensing molten material. A pipe is connected to the nozzle and carrying a heating resistor layer. The pipe is seated in an annular bracket. Spring contacts are mounted on the bracket, which contacts bear against the pipe at mutually opposite points and contact the heating resistor layer.

A device for centering an extrusion die for extruding an extrusion material wherein the device includes a housing means on or in which one or more centering elements are arranged or formed, wherein the one or more centering elements are configured to exert a centering force on an extrusion die to be centered, wherein the housing means comprises one or more fastening interfaces, by means of which the housing means can be fastened to an extrusion die to be centered or to an extrusion means comprising an extrusion die to be centered.

An extrusion die has first and second die bodies that define an extrusion cavity therebetween. The extrusion cavity has an inlet, a primary manifold that extends from the inlet along a flow direction, and an outlet that defines an elongate slot. In some examples, cavity has an intermediate chamber that extends from the primary manifold along the flow direction, the intermediate chamber having a back line and a front line that taper away from one another as they extend outwards towards opposing ends of the die. The primary manifold has a front end portion that is defined between opposing inner surfaces, at least one of inner surface tapering towards the other as it extends along the flow direction. In some examples, the inner surface has first and second curved portions that curve to provide a smoother transition from the primary manifold to a downstream chamber of the extrusion cavity.