To apply elastomer as insulation or sheathing to the conductor, the material is processed in an extruder. Hot extruders are used for this purpose, which usually consist of a motor, barrel, screw and extrusion head.
In the first step, the plastic granulate is fed into the barrel via a hopper and continuously melted with the help of frictional energy. The screw, as it is called, conveys and compresses the molten mass, which is then shaped with constant pressure via the extrusion head and a suitable die. Pressure and processing temperature vary depending on the material used.
Following extrusion, crosslinking must be carried out in the case of elastomers. This "upgrading" is what makes it possible to use the material in environmental conditions that it would otherwise not be able to withstand.