A finishing shaft for printing and textile production needs two properties simultaneously: a smooth, mark-free surface that does not contaminate the product, and durability against constant abrasive contact with paper or fabric. A metal shaft wears the product surface and corrodes on moisture; a rubber layer is soft but wears quickly and leaves pigment. Polyurethane shaft coating from TIMOL solves this: wear resistance 2-5 times higher than rubber, no corrosion, no marks on the product, and the ability to restore the same shaft by re-lining rather than purchasing a new one. This article explains the lining technology, material comparison in numbers, and how to order shaft coating.
What Polyurethane Shaft Lining Is
Shaft lining (from German Futter — lining) is the application of a functional layer of polymer material to the working surface of a metal shaft or roller. The metal core carries the structural loads — bending, torsion, operating forces in the drive — and the polyurethane layer is responsible for the working surface: it takes abrasion, impact, friction, and contact with the product or transported material.
This separation of functions gives the lined shaft an advantage over both a solid metal shaft and a solid polyurethane one. A solid metal shaft is strong but wears the contact surface, corrodes in moisture, and transmits vibration. A solid polyurethane shaft is limited in strength for large diameters and lengths. A lined shaft combines both: structural strength of metal and a wear-resistant, resilient working surface of polyurethane.
The polyurethane is cast onto the prepared metal surface rather than bonded in a separate operation. The shaft is cleaned of old coating and surface oxidation, degreased, and coated with an adhesion primer that creates a chemical bond between the polymer and metal. The polyurethane is then poured into a mould around the shaft and polymerises directly on the metal. The result is a monolithic coated shaft where the layer adheres to the metal for the full service life without delamination under vibration and bending. Substrate preparation and lining technology are described in the reference information section.
Why Polyurethane Coating Outperforms Rubber and Steel
The comparison covers three main materials used for shaft working surfaces. The table shows the parameters that determine service life and operational suitability.
| Material | Abrasion DIN 53516, mm³ | Operating t, °C | Density, g/cm³ | Tensile strength, MPa | Oil resistance | Corrosion resistance | Impact damping |
|---|---|---|---|---|---|---|---|
| Polyurethane TIMOL | 38-39 | -60…+100 | 1.05-1.25 | 39-87 | excellent | excellent | good |
| SBR rubber | 100-200 | -40…+80 | 0.94-1.1 | 8-20 | poor | good | good |
| Structural steel St3 | n/a | -40…+500 | 7.7-7.9 | 370-700 | n/a | poor | poor |
Polyurethane wins across the parameters critical for a shaft working surface: abrasion 4-8 times lower than SBR rubber, oil resistance that rubber cannot match, corrosion resistance that steel lacks, and impact damping that steel does not provide. Rubber is elastic and damps impact, but wears quickly and swells in oil contact, losing its geometry. Steel is strong and heat-resistant, but corrodes, transmits every impact to the structure, and in printing and textile applications damages the product surface.
Engineer’s tip: before ordering shaft lining, check the condition of the metal core. Cracks, deep pitting, or significant bending of the shaft are reasons for replacing the core rather than applying a new coating — even a high-quality layer on a damaged substrate will delaminate prematurely. A shaft that is geometrically sound but has surface wear or a corroded surface is the ideal candidate for lining: the metal continues its full service life, and the restoration cost is several times lower than a new shaft.
Applications: Which Shafts Are Lined with Polyurethane
Finishing shafts for the printing industry receive a polyurethane coating because the layer does not release pigment onto the printed sheet, is resistant to printing inks and solvents, and provides a controlled friction coefficient for stable sheet feed. In the textile industry, polyurethane-coated shafts pull and guide fabric without marking or snagging fibres.
In the paper and pulp industry, polyurethane rollers for paper web guidance and pressing work in a wet abrasive environment where rubber wears quickly and metal corrodes. The combination of oil resistance and corrosion resistance of polyurethane makes it the standard material for shafts in oil-wetted nodes of machine tools and presses.
In food processing, polyurethane-coated shafts meet hygiene requirements: no pigment transfer, no moisture absorption, resistance to food acids and washing solutions. In agricultural machinery — seed dressers, sorting machines, grain conveyors — polyurethane rollers work in an abrasive environment with dust and chemicals without corrosion. The full range of shaft lining by industry is covered in the services section; the product catalogue by equipment type is at /katalog.
Re-Lining: A Second Life for a Worn Shaft
The economic advantage of polyurethane lining that distinguishes it from other solutions is re-lineability. When the working layer wears down to the minimum permissible thickness, the shaft does not go to scrap: the old polyurethane is stripped, the metal surface is inspected, re-prepared, and a new layer is cast. The metal core continues in service for the second and sometimes third lining cycle.
For large-diameter finishing and printing shafts — where the metal part itself is expensive — re-lining reduces restoration cost by 3-5 times compared to a new shaft. Even for standard-size rollers, re-lining saves machine time and lead time: the customer sends the shaft to the factory, it is lined and returned, while a new shaft would require ordering, manufacturing, and waiting.
Restoration at a customer site is also possible for large-diameter shafts that are difficult to transport: a factory team arrives with the equipment and performs lining in place. Cost in this case is agreed individually and depends on shaft dimensions and working conditions. For consultation on re-lining and restoration, contact TIMOL factory.
How to Order Polyurethane Shaft Coating
To place an order, provide the shaft dimensions (length, diameter, type of surface to be coated) and describe the operating conditions: shaft function, contact medium (dry, oily, wet, product contact), temperature, rotational speed, and load per linear metre. Based on this data the technologist selects hardness, formulation, and coating thickness.
TIMOL factory accepts both new shafts to be coated for protection and worn shafts to be restored. Both single shaft restorations and batch production for a fleet of equipment are handled. The free-casting process ensures precise dimensions and full-contact adhesion of the layer to the metal. For consultation and ordering, contact TIMOL factory. Engineers will assess the shaft condition, select the optimal formulation, and estimate the full coating service life.