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.