Different types of heads and dies
Extrusion lines in the cable industry. - Manufacturing steps

The plastic material exits the extruder in the form of a rod. An extrusion head is needed to shape this material into a tube, which is then placed on a conductor (to insulate a wire) or on an assembly of wires (to sheath it).

What's more, the extruder outlet flow is parallel to the extruder axis, whereas the formed insulation tube must be perpendicular to it, to allow the conductor (or wire or wire assembly) to pass through. Indeed, a head whose formed tube would have an axis parallel to the screw would prevent the conductor from passing through. This function is performed by the connection between the extrusion head and the trumpet.