BINDERS

Although often considered incidental in the design of a cable, there are many reasons, both production and performance based for applying foils and tape binders.

The two primary types of tapes and foils used by Habia Cable are polyester (also known as mylar) and PTFE.

Each is available in a hard ‘foil’ and soft ‘tape’ version. Polyester is typically used for general purpose and halogen free constructions whilst PTFE provides a high temperature option. 

Other tapes and foil include:

• - Al/Pr foil - A polyester-backed, aluminium foil used for electrical screening.
• - Polyimide - Foil used for high temperatures and high radiation. Can be FEP coated for sintering.
• - Low noise - Carbon-loaded tape that can reduce electrical noise and interference.
• - Mica - Used as a flame barrier in Habiaflame2 constructions.
• - Mμ-Metal - A metallic foil that provides magnetic shielding.
• - Water-swellable - Used to absorb water and prevent it from tracking through the interstices of the cable and into the connector.

Cable manufacture is a process that has to be carried out in many stages. It is therefore often necessary to apply a foil or tape in order to physically hold a cable together as it moves between the different stages in production. As a general rule, any cable with 8 or more cores in the final layer of cabling, or a cable with a filling compound to remove all air-spaces in the cable will require a foil or tape to be applied for this purpose.

A typical overlap is between 25% and 50%.

 

Braided electrical screens and armours can be abrasive to the cores over which they are placed. The application of a foil or tape can often prevent wear and tear to the cores within the cable as it is flexed.

Some tapes and foils such as PTFE are very soft and low friction. This can enable the elements within a cable to move past one another, improving both the overall flexibility and flex-life of the cable.

 

The addition of a binder can also improve the roundness of a cable, particularly when used beneath a pressure extruded outer sheath. Pressure extrusion allows the sheath of the cable to be made perfectly smooth and round, however this pressure also forces the sheath material into the interstices of the braid and/or cores which makes it very difficult to remove the sheath by hand and virtually impossible to remove with automated cut-and-strip equipment. The addition of a binder gives a smooth surface over which to extrude, enabling the sheath to be removed with relative ease.