An extruder is a continuous pressing device used in production, which works on the principle of Archimedes’ screw. Extruders may have one or two worm shafts.

In cable technology, for example, the material for extrusion may be granulated plastic for cable insulation, which is heated, compressed, mixed and pressed through the die under high pressure.

Extrusion was in use as early as the late 19^th century, when the process was used for producing submarine telegraph cables.