The extrusion head is the processing tool that shapes the extrudate i.e. the tool that
determines shape, properties, structures and dimensions of the extrudate as well as
mutual position of the elements in the extrusion process. The extrusion head is the tool
with an open forming cavity i.e. the extrusion die. The extrusion head has to ensure the
occurrence of proper physical and chemical processes in the polymer during its flow
through the flow channels [65, 67].
The extrusion head is fixed to the end part of the plasticizing system of the extruder.
Small extrusion heads are fixed mainly by means of bolt connections or bolt-pin
connections (usually hinge-type connections) or by means of a screwed shape ring.
Larger extrusion heads are fixed by means of bolt-pin connections, shape semi-rings that
are attached and fixed with bolts as well as by means of bolt connections that are very
often provided with a vertical support on the extruder foundation. More and more
frequently, auxiliary preparatory devices such as a polymer filter, a gear pump or a static
mixer (or a set of two or three such devices) are attached and fixed to the plasticizing
system. The extrusion head, usually provided with a vertical support, is connected to the
last preparatory supplementary device.