A worn bushing or roller in an assembly is done for, and there is no ready equivalent at hand: the factory catalogue does not cover the rare size, and waiting for delivery means equipment downtime. A polyurethane round bar solves the task on the spot: a part of precise size is turned from a cast blank in a couple of hours, and it lasts many times longer than a rubber or caprolon equivalent. This article explains how to choose a round bar, why it beats competing plastics and where to order a blank in Dnipro.
Why a polyurethane round bar is needed
A round bar is a cast blank of cylindrical shape that serves as raw material for the mechanical making of small parts. Its main advantage is versatility: from a single blank a turner produces any body-of-revolution part for a specific assembly, without waiting for a finished item from the catalogue. This is critical for repair services that restore equipment without stopping for a long delivery.
Polyurethane as the blank material combines machinability with high wear resistance. A round bar lends itself well to turning, cutting, drilling and grinding, while giving minimal waste. A turned part inherits all the properties of the material: abrasion per DIN 53516 at 38-39 mm³, operation in the range from -60 to +100 °C and resistance to oils and moisture.
Bushings, rings, rollers, guides, couplings, gears, cuffs for hydraulic and pneumatic cylinders and dampers are made from a round bar. In noisy mechanisms such parts reduce vibration and impact loads, which extends the service life of neighbouring assemblies and lowers noise in the workshop.
Comparison of a round bar with caprolon and UHMW-PE
For machining, polyurethane competes with two plastics: caprolon (polyamide PA6) and ultra-high-molecular-weight polyethylene (UHMW-PE). The table sets their key characteristics against each other using standard reference sources.
| Characteristic | TIMOL polyurethane | Caprolon PA6 | UHMW-PE |
|---|---|---|---|
| Abrasion DIN 53516, mm³ | 38-39 | 30-90 | 15-30 |
| Operating temperature, °C | -60…+100 | -40…+100 | -200…+80 |
| Tensile strength, MPa | 39-87 | 60-85 | 17-45 |
| Shore hardness | 85A-95A | 75D-85D | 60D-70D |
| Rebound elasticity, % | 34-61 | 5-15 | 5-10 |
| Moisture absorption, % | minimal | 2.0-8.0 | minimal |
Each material has its own niche. UHMW-PE slightly outperforms polyurethane in pure abrasion (15-30 versus 38-39 mm³) and has low friction, but it deforms under load and is not elastic at all (rebound 5-10 %). Caprolon is the hardest and strongest in tension (60-85 MPa), so it gives precise dimensions, yet it absorbs up to 8 % moisture and swells, and cracks on impact. Polyurethane wins where impact, vibration and moisture are added to wear resistance: its rebound elasticity of 34-61 % versus 5-15 % for the plastics makes the part resistant to dynamic loads.
Turner’s tip: polyurethane is springy, so when turning harder grades keep the cutter sharp and the feed moderate, otherwise the material will push away and give a wavy surface. Soft grades below 90 Shore A are better not turned but cast straight to size. After machining, leave a small stock: the part settles slightly, so bring the final size to the fit by grinding.
Hardness and choosing a blank for the task
The right choice of hardness determines both the machinability of the round bar and the behaviour of the finished part. For parts with precise geometry, threads and tight tolerances, a harder polyurethane in the 60-70 Shore D zone is taken: it springs less under the cutter and holds its size. For elastic elements, seals and dampers, softer grades closer to Shore A are chosen, which absorb impact better.
The overall hardness range of the factory’s products spans from 50 Shore A to 70 Shore D, which covers practically all tasks of machining and casting. The technologist helps select a grade to suit the function of the part, the machining method and the working conditions of the assembly. You can review the available blank and product positions in the catalogue, and the reference information about the material in the relevant section.
It is important to remember how polyurethane behaves under the cutter. Unlike metal, the polymer is springy and pushes away from the tool slightly, so for a precise part harder grades in the Shore D zone suit better than soft ones. The material is also sensitive to overheating: at a high cutting speed the surface may melt, so the feed is kept moderate and the tool sharp. Following these rules lets you obtain a clean surface and precise size without additional finishing.
Round bars made to size in Dnipro
Blanks at the TIMOL factory are cast by free casting into open and closed forms. The technology yields a solid billet with no seams or internal cavities, which matters for subsequent machining: a monolithic blank has no voids that show up under the cutter and spoil the part. The round bar comes out uniform across its whole cross section.
If the standard diameter is not in stock, the blank is cast to your drawing or a sample of the part. It is enough to specify the required diameter, length and desired hardness, or to hand over the worn part from which the dimensions will be taken. The factory’s location in Dnipro, a major transport hub, simplifies logistics across the whole of Ukraine. More about the made-to-order blank production service is in the services section.
How to order a polyurethane round bar at the TIMOL factory
You can buy a polyurethane round bar in Dnipro directly from the manufacturer, with no intermediary markups. Direct contact with the factory lets you obtain a blank of the required diameter and hardness for a specific part, and if needed a finished item turned to size.
To place an order, specify the diameter and length of the blank, the desired hardness and describe the part you plan to make. If the parameters are unknown, the technologist will help determine them from a sample or drawing. You can contact the factory and agree an order through the contacts page. A blank for a specific task saves machining time and gives a part with a predictable service life.