Over jacketing extrusion

Over jacketing extrusion allows for the application of an outer layer of plastic onto an existing wire or cable. This is the typical process for insulating wires.

There are two different types of die tooling used for coating over a wire, tubing (or jacketing) and pressure. In jacketing tooling, the polymer melt does not touch the inner wire until immediately before the die lips. In pressure tooling, the melt contacts the inner wire long before it reaches the die lips; this is done at a high pressure to ensure good adhesion of the melt. If intimate contact or adhesion is required between the new layer and existing wire, pressure tooling is used. If adhesion is not desired/necessary, jacketing tooling is used instead.