Extrusion machines force or pull unformed material into
alignment guides and shaped dies to produce lengths of stock
forms and cross-sectional shapes. They are used mainly in the
plastics, metals, and composite-forming industries. Extrusion
machines are also used in automotive, aerospace, and
construction applications. The basic parts of an extruder
include a tubular barrel, a revolving screw, and a ram or
plunger within the barrel. An extruder also has a hopper at one
end from which the material to be extruded is fed to the screw,
ram, or plunger. A die at the opposite end is used for shaping
the extruded mass. Extrusion machinery that can cut extruded
materials into short or long intervals is also available. There
are many different types of extrusion machines. Often, suppliers
categorize products by the material extruded or the extrusion
technology. For example, plastic extruders are designed to shape
plastic materials in pipe extrusion, profile extrusion, and
sheet extrusion applications. Thermoplastic ex