PU-Coated Steel Wire Rope Extrusion Line

PU-Coated Steel Wire Rope Extrusion Line

The PU-coated steel wire rope extrusion production line is a specialized automated complete set of equipment used to continuously and uniformly coat a layer of polyurethane (PU) elastomer onto the surface of bare steel wire rope. Its core process utilizes a plastic extruder to tightly coat molten PU material onto the steel wire rope moving at a constant speed. After cooling and setting, the final PU-coated steel wire rope product is formed.
Compared to PE and PVC, the PU coating layer offers unique performance advantages, which make the production line and technical requirements more specialized:
Exceptional Abrasion Resistance: PU's wear resistance is extremely outstanding, often considered 5-10 times better than ordinary rubber, ranking among the best of all polymers.
High Elasticity and Flexibility: Good rebound resilience and high elongation at break, capable of withstanding repeated bending and impact.
Excellent Oil Resistance and Tear Resistance: Good resistance to grease and mineral oils, coupled with high tear strength.
Wide Hardness Range: Shore A hardness can be adjusted from approximately 70A to 95A through formulation changes, meeting needs from soft to tough.
Good Fatigue Resistance: Maintains performance under dynamic loads, ensuring a long service life.
High Coefficient of Friction: Unlike the smooth surface of PE, PU provides greater friction, suitable for anti-slip transmission and traction applications.

Production Line Composition

A complete PU-coated steel wire rope extrusion production line, based on a general structure, has specific requirements for PU's processing characteristics and mainly consists of the following systems:
Pay-off System
Core Equipment: Pay-off stand.
Function: Supports and releases the bare steel wire rope from the carrier reel.
Key Requirement: Provides extremely stable and precise pay-off tension control. Tension fluctuations directly affect the uniformity of the PU coating layer.
Pre-treatment System
Core Equipment: Cleaning device, Pre-heater.
Function:
Cleaning: Must thoroughly remove all oil, moisture, and impurities from the steel wire rope surface. Any contamination will severely affect the bonding between PU and the wire rope.
Pre-heating: Precise pre-heating (temperature typically ranging from 120-180°C, depending on the PU formula) is crucial to ensure optimal bonding between the PU melt and the steel wire rope.
Extrusion System
Core Equipment: Precision extruder, PU-specific screw and barrel, Precision extrusion die (Head).
Function: Melts, plasticizes TPU (Thermoplastic Polyurethane) pellets, and extrudes them uniformly to coat the steel wire rope surface.
Extruder: Requires high temperature control accuracy. The screw and barrel usually feature special materials and design to adapt to TPU's viscous characteristics and potential shear heat, preventing material degradation.
Head (Die): The design is critical. It must ensure uniform distribution of the PU melt, forming a coating layer with high concentricity. The flow channel design needs to minimize dead zones to prevent TPU stagnation and decomposition.
Cooling and Setting System
Core Equipment: Cooling water tank.
Function: Cools and solidifies the high-temperature PU coating layer.
Process: The cooling process needs to be gradual. As PU elastomer is sensitive to cooling rate, gentle gradient cooling is typically employed to avoid product deformation, uneven shrinkage, or compromised elasticity due to internal stress.
Pulling System
Core Equipment: Puller (high-precision dual-caterpillar type).
Function: Provides smooth, slip-free pulling force.
Key Requirement: Speed control must maintain ultra-high precision synchronization with the extrusion speed. This is key to ensuring the thickness and surface quality of the PU coating layer.
Take-up System
Core Equipment: Take-up stand.
Function: Winds the finished product neatly.
Type: Active take-up, equipped with a precision traverser and constant tension control, ensuring neat winding and preventing crushing or deformation of the elastic PU layer.
Electrical Control System
Core Equipment: High-performance PLC, Touchscreen (HMI), High-precision temperature control modules, Frequency converters, etc.
Function: Achieves precise closed-loop control of parameters such as temperature, tension, and speed, with particularly high requirements for the temperature control of the extruder and pre-heater.

PU-Coated Steel Wire Rope 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

PU-Coated Steel Wire Rope Extrusion Line Application

The PU-coated steel wire rope extrusion production line is a special extrusion line with extremely high requirements for precision and process technology. Its resulting PU-coated steel wire ropes perfectly combine the strength of steel wire rope with the unparalleled wear resistance and elasticity of polyurethane, primarily serving high-end industrial and consumer product fields with stringent demands on dynamic performance, durability, and special physical properties. Specific applications are as follows:
Industrial Machinery and Automation
High-wear transmission ropes/belts: For precision transmission, synchronous drive applications, such as in textile machinery, printing machinery, and internal robot drives.
Cleaning equipment brush core shafts: Serve as the central skeleton for brushes in cleaning machines and sweepers, offering abrasion resistance and resistance to chemical cleaners.
Escalator drive ropes: Meet high safety standards, offering wear resistance and smooth operation.
Sports and Fitness Equipment
Strength equipment steel wire ropes: Used for weight stack cables in fitness machines, being flexible, quiet, and durable.
Ski lift haul ropes: Resistant to low temperatures and abrasion, with good handling feel.
Special Vehicles and Marine
Remote-control model vehicles: Control cables for models like aircraft and boats, offering flexibility and responsive control.
Marine control cables: Used in mechanical control systems for some small yachts.
High-end Furniture and Medical Equipment
Lifting cables for height-adjustable office chairs and medical beds: Operate quietly, smoothly, and are durable.
Other Special Fields
Wear-resistant guide ropes: Serve as guidance and support in equipment requiring frequent reciprocating motion.
Traction ropes in oily environments: For use in industrial environments where oil contamination is present.