Wire & Cable Extrusion Process
What Is Cable Extrusion?
Cable extrusion is the process of melting a polymer and applying it around a conductor to form insulation or a protective jacket. The conductor is drawn through a crosshead die where molten material, typically PVC or polyethylene, coats it at a controlled thickness, then cooled in a water trough to set the layer. It is how a bare conductor becomes a finished, protected cable.
| Construction | What it is | Typical use |
|---|---|---|
| Single-layer | One insulation or jacket layer over the conductor | Hookup wire and simple cable constructions |
| Dual / co-extrusion | Two layers applied in a single pass | Color-coded skins, or a tough outer over a softer inner |
| Multi-layer | Three or more bonded layers | Combined electrical and mechanical requirements |
| Foam-skin | Foamed inner layer with a solid outer skin | Controlled impedance and dielectric tuning |
During the extrusion process, wire and cable is coated with a protective sheathing or insulation using a specific type of material – typically a thermoplastic such as Polyvinyl Chloride (PVC) or Polyethylene (PE). The plastic is first melted in an extruder, which then forces the liquefied plastic into what is known as a crosshead die.
The actual coating or extrusion of the wire occurs in the crosshead die where the wire is pulled through the die containing the liquefied plastic. As the coated wire exits the die, it is immediately immersed into a water bath that cools and sets the meted plastic onto the conductor. During the extrusion process, extrusion operators continuously inspect cooled wire for compliance with size as the product is coiled onto a spool.
At Mercury Wire, we offer a broad selection of dies and crossheads that accommodate a variety of sizes and configurations. Our processes and equipment are designed to handle traditional jackets, foam skin, and customized coatings. Our capabilities and expertise allow us to provide you with high quality extrusion processes including:
- Single Layer
- Dual Layers
- Multi-Layers
- All with Multiple Stripping and Printing Options
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QWhat is cable extrusion?
Cable extrusion melts a polymer and applies it around a conductor to form insulation or a jacket. The conductor passes through a crosshead die, gets coated at a set thickness, and is cooled to solidify the layer.
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QWhat is the difference between insulation extrusion and jacket extrusion?
Insulation is extruded directly onto the conductor for electrical performance. Jacket extrusion applies the outer protective layer over the assembled cable for durability. Both use the same core process with different materials and wall thicknesses.
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QWhat materials can be extruded onto wire and cable?
Common thermoplastics include PVC, polyethylene (PE), polypropylene (PP), polyurethane (PUR), chlorinated polyethylene (CPE), and nylon. Material choice depends on temperature, flexibility, and environmental requirements.
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QWhat is foam-skin extrusion?
Foam-skin extrusion pairs a foamed inner layer with a solid outer skin. The foam lowers the dielectric constant for controlled impedance, while the skin protects the surface and holds dimensional consistency.