A maintenance engineer needs a bushing for a hydraulic cylinder — a non-standard diameter that is not available as a finished product. Standard options: machine it from a capron rod that absorbs moisture and cracks in frost, from PTFE that creeps under load, or from a polyurethane rod that combines machineability with wear resistance, elasticity, and chemical stability. Polyurethane rod (round stock) from TIMOL allows any rotational geometry to be machined on a lathe: bushings, seals, wheels, guides, and dampers to the exact required diameter and hardness. This article covers properties, machining methods, comparison with analogues, and how to order in Ukraine.
What a Polyurethane Rod Is and Why It Is Used
A polyurethane rod is a cast blank of circular cross-section produced by the free-casting process in a closed mould. The rod is the source material for machining: a finished part of the required geometry, diameter, and surface quality is obtained from it on a lathe or milling machine. This allows non-standard sizes, complex profiles, and close-tolerance fits to be produced where a finished cast part would be too expensive or impossible to obtain.
Rods are used where the geometry of the part must be matched precisely to the seat. A bushing for a worn shaft, a cuff for a hydraulic cylinder, a guide for a press, a wheel for a trolley — all of these can be machined from a polyurethane rod to the exact diameter and fit. The rod is also convenient for prototyping and repair: the engineer machines the part on site without waiting for a mould to be made. The product range produced from rods is presented in the product catalogue.
A separate advantage of the rod format is flexibility in hardness selection. Hardness is set at the casting stage, from 50 Shore A to 70 Shore D, so a soft formulation is available for a seal or damper and a hard formulation for a wear-resistant guide or gear. Both grades are machinable by the same methods, and the part receives both the required geometry and the required elasticity from a single rod blank.
Machining Properties and How to Work with Polyurethane Rods
Polyurethane round stock is machined on standard metalworking equipment — a lathe, milling machine, or grinder — without special tooling. The material cuts cleanly without chipping or tearing, holds the set diameter to an accuracy of ±0.1 mm, and does not leave burrs when well-sharpened tooling is used. This allows complex profiles — grooves, flanges, internal bores, tapers — to be machined with quality comparable to metal.
The working recommendations for the machinist are brief: use sharp tooling, reduce feed rate compared to metal, and apply cutting fluid (water-based emulsion or compressed air) to prevent heat build-up at the contact zone. The main risk is thermal deformation: if the tool is blunt or the feed rate is too high, friction heats the polyurethane locally, the material temporarily softens, and the part becomes oversized. With sharp tooling and moderate speed this effect is eliminated and the machined surface holds tolerances for the service life of the part.
Polyurethane round stock is also sawn, ground, and bonded to metal substrates using structural adhesives. A ground polyurethane surface on a shaft or roller gives a wear-resistant and resilient working layer. The machining process and adhesion to metal are covered in the reference information section.
Comparison of Polyurethane Rod with Capron, UHMW-PE, and PTFE
Rods from different materials compete in the same applications: capron (PA6/PA66), UHMW-PE, and PTFE are the main alternatives to polyurethane in machining practice. The table shows the key parameters from which the choice for a specific node follows.
| Material | Abrasion DIN 53516, mm³ | Operating t, °C | Hardness | Rebound elasticity, % |
|---|---|---|---|---|
| Polyurethane TIMOL | 38-39 | -60…+100 | 85A-95A | 34-61 |
| Capron PA6/PA66 | 30-90 | -40…+100 | 75D - 85D | 5-15 |
| UHMW-PE | 15-30 | -200…+80 | 60D - 70D | 5-10 |
| PTFE (fluoroplastic) | 200-500 | -200…+260 | 50D - 65D | n/a |
UHMW-PE has the best abrasion, but its rebound elasticity is only 5-10 %, so parts made from it take impact rigidly without absorbing energy — in a dynamic node this means faster fatigue of the adjacent structure. Capron is close on abrasion but absorbs moisture (up to 8 % by mass), which causes swelling and dimensional change in a wet environment. PTFE is chemically inert and slippery, but its abrasion of 200-500 mm³ is the worst in the table, and under sustained compression it creeps — the part loses its geometry over time. Polyurethane finds the best balance: abrasion nearly as low as capron, rebound elasticity 6-13 times better, no moisture absorption, and a wider temperature range than capron.
Engineer’s tip: when ordering a rod for dynamic application — bushings, seals, shock absorbers — select a hardness in the middle of the Shore A range. A too-soft formulation deforms under load and does not hold tolerances; a too-hard one loses the elasticity that prevents edge cracking at the end of the machined bore. For sliding guides and gears, closer to Shore D. Always specify the operating medium: if there is oil, an oil-resistant formulation is selected at the casting stage.
Applications: What Is Machined from Polyurethane Rods
In hydraulics and pneumatics, polyurethane rods are the primary source material for seals, cuffs, and guide rings. The cuff profile requires exact dimensions and a clean surface — both are achieved on the lathe from a polyurethane blank. The cuff’s operating range of -60 to +100 °C covers the full range of conditions from cold-climate machinery to heated process cylinders.
In mechanical engineering and production equipment, rods are used for bushings, guide sleeves, pressure rollers, and wear elements that work against abrasion. Machining from a rod to the exact shaft diameter with the required interference fit gives better contact quality than a finished standard-size bushing. In noise and vibration applications — presses, stamps, impact machines — polyurethane rods are used to machine springs and dampers replacing metal springs: the material absorbs impact and reduces noise at the same time.
In conveyor and transport equipment, wheels for trolleys and carts are machined from hard polyurethane rods. A wheel machined from a rod with a hardness of 60-70 Shore D carries the load, wears slowly on a concrete floor, and does not mark the surface — this is critical for food production and clean-room environments. The full list of equipment types and industries served by TIMOL is available in the services section.
How to Buy Polyurethane Rods in Ukraine
To place an order, specify the required diameter, length, and hardness grade, and describe the part to be machined from it: this allows the factory technologist to recommend the optimal formulation. Standard diameters and hardness grades are in stock; non-standard dimensions are cast to order.
TIMOL factory is in Dnipro and ships throughout Ukraine. Both individual rods for a one-off repair and batches for production machining are supplied. Free casting keeps the price of a non-standard diameter reasonable: the mould cost is minimal, so even a small batch of rods is produced economically. For consultation, stock check, and ordering, contact TIMOL factory. Engineers will select the hardness, agree the dimensions, and arrange shipment.