Wire and Cable Extrusion

Wire and Cable extrusion allows for the conductive copper wires/cables to be insulated with a polymer coating. The main application areas are in telecommunications and electrical/electronics The wire/cable is pulled through a crosshead (T-shaped) die as molten polymer is coated around the whole circumference. Due to the molten nature of the polymer it coats not ony the outer circumference but also penetrates between the outer layers of a multi-strand wire/cable to allow for greater adhesion to the conductive metal. This allows for better strength when the cable is flexed and reduces the chances of splits and cracks as there is a greater thickness adhering to the cable/wire. Specialist compounds are used to impart colour, flame retardency, improved flexibility, greater wear resistance etc. In cases where a multiple coating is needed, for example where power cables need live/negative/earth to be combined, then a second stage will combine and overcoat the gathered pre-coated cables into one structure. There are various polymers used in wire coating applications. The characteristics of each polymer(s), are chosen for a specific purpose of flexibility, electrical properties, ability to withstand abuse, and durability. Typical polymers are as follows:

Polyethylene

Polyvinylchloride

Polyamide

Polybutylene terephthalate

Thermoplastic elastomers

Ethylene propylene copolymers

Polypropylene

Fluoropolymers