Plastic extrusion of tubes, hoses, pipes, profiles, cables and wires is a steady-state process for converting a thermoplastic raw material into a finished or semi-finished annular product.

The raw material is usually in the form of plastic pellets or powder, and the conversion takes place by forming a homogeneous molten mass in the extruder and forcing it under an extrusion die orifice pressure which defines the shape of the product's cross section. The formed material or extrudate is cooled and drawn away from the die exit at a controlled rate. This extrudate can then be wound on a spool, cut to a specified length or directed into another in-line process.