Extrusion is a well-known processing technology that has been developed
over the last century and spans many diverse industrial ﬁelds. Extrusion can be simply deﬁned as the process of forming a new material (the extrudate) by forcing a material through an oriﬁce or die under controlled conditions. The historical use of extruders, and especially of twin-screw extruders, has been
with the processing of foods and the manufacturing of plastics. Developments
in multiscrew extrusion-based processing have occurred throughout the
industrialized world, with the major early advances occurring in Germany,
the United Kingdom, and later in the United States.