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Polyurethane (PU) timing belts are high-performance, toothed power-transmission belts made of durable thermoplastic PU elastomer reinforced with high-strength steel or aramid (Kevlar) cords. These polyurethane synchronous belts combine superior wear resistance and low stretch, ensuring precise, synchronized motion. They excel in precision-driven environments like automated assembly lines, CNC machinery and robotics, and are widely used on conveyors, packaging machines and other material-handling systems where accurate, low-noise operation is critical.
Manufacturing Process of PU Timing Belts
Raw Material Preparation
The process begins with high-quality PU materials and tensile cords. PU may be supplied in granule or liquid resin form, often mixed with color pigments, anti-static agents, or other additives to enhance performance.
The cords—either steel wire or aramid fibers—are precisely cut and tensioned to meet design requirements. These cords form the skeleton of the timing belt, providing tensile strength and dimensional stability.
Extrusion and Pre-Forming
The PU material is melted and extruded through precision molds to create the basic belt profile and tooth geometry. This produces an open-ended belt section that can later be cut or welded into endless loops.
For sleeve or casting processes, PU is poured or layered onto a rotating drum or mandrel until the desired belt thickness is achieved.
Cord Embedding
The tensile cords must be evenly embedded within the belt body.
In casting (sleeve) processes, the cords are helically wound onto a mold under constant tension before PU is poured around them.
In continuous extrusion processes, the cords are fed directly into the molten PU as the belt is formed.
Cord tension and spacing are critical for achieving high tensile strength, low stretch, and long belt life.
Molding and Vulcanization
The formed belt is cured in a heated mold or vulcanization chamber, typically at 180–200°C. Under heat and pressure, the PU polymer cross-links tightly around the cords, producing a dense, precise, and uniform belt structure. Controlled cooling follows to prevent deformation and residual stress.
Tooth Finishing
After curing and cooling, the belt teeth are precision-machined to achieve perfect geometry. CNC milling or grinding ensures each tooth’s pitch, root, and flank meet strict tolerances—often within 0.02 mm.
Any burrs are removed, and belts are cut to the required length or width.
Surface Treatment and Backing Application
To improve wear resistance, reduce noise, or increase friction, additional materials can be applied to the tooth or back surface:
- PAZ fabric on the tooth side to reduce friction and noise.
- PAR fabric on the back side to enhance strength and slip resistance.
- Rubber, foam, or PVC coatings for conveying applications.
- Custom weld-on profiles such as cleats or guide bars for positioning or transport functions.
Quality Inspection and Packaging
Every timing belt undergoes strict quality control before shipment, including dimensional inspection (width, pitch, total length), tensile testing, tooth profile verification, and visual checks.
Qualified belts are cleaned, coiled, labeled, and packaged to prevent deformation during transport—ready for immediate installation upon delivery.
Puteken’s Advantages as a Professional PU Timing Belt Manufacturer
Strict Material Quality Control
Puteken implements rigorous inspection standards for every batch of raw materials and in-process production. We use high-purity polyurethane and advanced testing methods to prevent early belt wear and minimize machine downtime. With ISO-certified manufacturing systems and SPC statistical controls, Puteken ensures consistent belt hardness, elongation, and cord tension across all production lots.
Precision Tooth Consistency
Every PU timing belt produced by Puteken is processed with CNC machining and high-precision molds. Our production accuracy reaches ±0.02 mm, guaranteeing perfect tooth geometry and smooth pulley engagement. This precision delivers stable transmission performance and reduced noise for high-speed industrial applications.
High-Volume Production Capacity
Puteken operates multiple automated extrusion lines and curing systems, ensuring stable, large-scale output with fast delivery. Whether you require bulk orders of standard PU timing belts or urgent replenishment batches, we provide a dependable supply chain and efficient logistics support to keep your operations running smoothly.
Comprehensive OEM/ODM Customization
As a flexible manufacturer, Puteken offers a wide range of customization options — including special lengths, widths, tooth profiles, surface coatings, and backing materials. We also support branding, cleat welding, and functional modifications such as anti-static or flame-retardant treatments. Our engineering team works closely with customers to deliver tailored PU timing belt solutions that perfectly match each industrial application.
