Power Cord Extrusion Line

Power Cord Extrusion Line

A power cord extrusion production line is a specialized complete set of equipment used for manufacturing the insulation layer and sheath of power cables. Its core process involves heating plastic (such as PVC, rubber, etc.) to melt it, and then continuously and uniformly coating it onto the metal conductor (like copper or aluminum) through a precision die, forming the insulation protection and outer sheath.

Core Components

A complete power cord extrusion production line mainly consists of the following systems, arranged in the order of material flow:
Pay-off System
Function: Bears and smoothly releases the conductor (copper/aluminum rod or preliminarily processed core wire).
Types:
Passive Pay-off: Relies on the pulling force from the downstream haul-off.
Active Pay-off (Key): Equipped with a motor and tension control system to ensure the conductor enters the die head with constant tension, avoiding thinning or uneven internal stress, and ensuring consistent conductor diameter.
Preheating System
Function: Preheats the conductor before it enters the extruder die head.
Purpose:
Removes surface moisture from the conductor, preventing bubble formation during extrusion.
Enhances adhesion between the plastic melt and the conductor, reduces internal stress, and improves insulation layer quality.
Extruder System
Function: Plasticizes plastic pellets (e.g., PVC compound) into a uniform molten state through heating and shear.
Core Components:
Hopper: Used for storing and feeding plastic pellets.
Screw and Barrel: Core working components. Screw design varies based on plastic characteristics (e.g., PVC or rubber), responsible for conveying, compressing, melting, and mixing the plastic.
Heating/Cooling System: Precisely controls the temperature of each section via electric heating bands and air/water cooling systems, preventing plastic degradation.
Drive Motor: Provides stable power for the screw, requiring steady rotational speed.
Die Head and Tooling
Function: Guides the molten plastic and shapes it precisely and concentrically around the conductor.
Types:
Pressure Die: Mainly used for extruding the sheath layer, providing a tight overall jacket for the core wire.
Semi-Pressure Die/Tubing Die: Used for extruding the insulation layer, capable of achieving very high concentricity, ensuring uniform insulation thickness.
Cooling System
Function: Rapidly cools and sets the cable coated with high-temperature molten plastic.
Form: Segmented cooling water trough. Water temperature needs precise control; cooling too fast or too slow affects the crystallinity and physical properties (like flexibility) of the insulation layer.
Online Diameter Gauge (Key Quality Control Equipment)
Function: Measures the cable's outer diameter in real-time, without contact, and displays it digitally or as a waveform graph.
Importance: Enables closed-loop control. It can instantly detect diameter variations (e.g., eccentricity, oversize/undersize) and feed back to the control system to automatically adjust process parameters, ensuring product tolerances remain within standard limits.
Spark Tester 
Function: Performs online detection of defects like pinholes or scratches in the insulation layer. It applies high voltage to the insulated wire; any defect causes a spark discharge which is recorded, ensuring insulation integrity.
Printing Device
Function: Continuously prints trademarks, specifications, model numbers, rated voltage, and other identifications on the cable sheath for easy recognition and traceability.
Caterpillar Haul-off
Function: Provides stable pulling force to draw the cable through the entire production line at a constant speed.
Requirement: Speed must be highly stable and jerk-free, typically using a belt-type haul-off to prevent slipping.
Take-up System
Function: Neatly winds the finished cable onto a reel.
Types:
Passive Take-up: Driven by the haul-off.
Active Take-up (Preferred): Equipped with a motor and tension control system, enabling constant tension winding, ensuring neat and consistent reel winding, and avoiding cable deformation.
Control System
Function: Centrally controls the entire production process.
Composition: Typically centers around a PLC (Programmable Logic Controller) and a touch screen HMI (Human-Machine Interface).
Control Parameters: Precisely controls temperature, screw speed, synchronization between haul-off and take-up speeds, tension, etc. Advanced systems can integrate the diameter gauge to achieve Automatic Process Control (APC).

Power Cord Extrusion Line Datasheet

Model	30	40	50	60	70	80	90
Screw Diameter (mm)	φ30	φ40	φ50	φ60	φ70	φ80	φ90
Screw L/D Ratio	25:1	25:1	26:1	26:1	26:1	26:1	26:1
Extrusion Amount (kg/hr)	25	40	70	100	140	200	250
Outlet Wire (mm)	0.2-1	0.4-3	0.8-5	1-8	2-15	3-25	5-35
Total Power (KW)	18	20	25	33	40	55	63
Traction Power (KW)	2.2	2.2	4	4	4	5.5	5.5
Production Speed (m/min (Max.))	600	600	600	500	500	300	300
Take-up Spool (mm)	φ200-400	φ300-500	φ400-630	φ400-630	φ500-630	φ800-1000	φ1000-1250

Power Cord Extrusion Line Application

The power cord extrusion line is a foundational equipment in the wire and cable industry. Its stability and precision directly determine the quality of the power cable—whether the insulation is safe and the sheath is durable. It is primarily applied in the following two core processes:
Conductor Insulation Extrusion
Content: This is the most basic and critical application. PVC or other insulating materials are melted and then precisely extruded onto a single or stranded copper conductor to form an insulated core wire.
Requirements: Ensure the concentricity and uniform thickness of the insulation layer, which directly relates to the product's voltage resistance capability and electrical safety performance.
Outer Sheath Extrusion
Content: Extrude an outer sheath over the cable core that has already undergone insulation, cabling (stranding of multiple cores), and even shield braiding.
Requirements:
Tight Encapsulation: The sheath should fit snugly against the cable core, providing good mechanical protection.
Uniform Thickness: Provides balanced protection against abrasion, oil, weather, flame retardancy, etc.
Material Variety: Select sheath materials according to the application scenario, such as:
PVC: Universal type, low cost, offers certain flame retardancy.
Rubber: Extremely flexible, cold-resistant, and abrasion-resistant, used for heavy-duty mobile equipment cables.
Low-Smoke Zero-Halogen (LSZH): Produces low smoke and is non-toxic when burning, used in densely populated places (e.g., subways, shopping malls).