Rubber rollers are essential machine components without which the production of many items would be impossible. From transporting material to precisely applying paints, varnishes and adhesives, rollers play an important role in many machines.
Regenerating the rubber coating of rollers or grinding rubber rollers is an economically sound solution for manufacturing companies, as it is much cheaper than purchasing new rollers.
This process ensures their repeated use, eliminating the need for new rollers. The process is designed to ensure optimal performance and consistent results in applications such as printing, lamination, varnishing and transporting manufactured components. Furthermore, when the rubber is damaged or worn, it can be repaired relatively easily, quickly and cheaply compared to purchasing a new roller. The use of rubber on rollers protects products thanks to the hardness of the rubber being selected appropriately for a given application. Thanks to its properties and flexibility, rubber often outperforms steel or aluminium rollers.
Using different types of rubber allows us to adapt the rollers to your needs in terms of shock absorption and resistance to impact, abrasion and corrosion. Properly selected rubber is also resistant to the chemicals it comes into contact with, such as solvents, paints, varnishes, oils and UV rays.
In this article, we will describe how to regenerate industrial rubber rollers through a series of repair measures.
What causes rubber roller wear?
Before discussing how to regenerate rubber rollers in detail, it is important to understand the main causes of wear and tear on these components.
- Mechanical wear: continuous use, friction and pressure cause abrasion to the roller surface, reducing its effectiveness.
- Oxidation: rubber exposed to oxygen and ozone loses its elastic properties over time and cracks.
- Chemical reaction: contact with aggressive chemicals such as oils, varnishes, paints, acids or solvents can lead to material degradation.
- Temperature changes: Extreme temperatures can cause the rubber to expand and contract, resulting in cracking and loss of properties.
- UV radiation: prolonged exposure to sunlight leads to ageing and degradation of the material.
How can the life of rubber rollers be restored? Rubber coating or roller grinding?
Although mechanical damage, ageing and wear and tear are inevitable, a number of maintenance and repair measures can effectively extend the life of rubber rollers and restore some of their vitality.
Remdruk, a company specialising in the regeneration and production of new rollers, offers rubber roller regeneration through hot rubber vulcanisation.
They also offer rubber roller grinding on an ad hoc basis to refresh the surface of the roller. A rubber roller can be ground multiple times until it reaches the minimum required diameter for each specific machine.
Roller rubberizing. How does it work in practice?
First, the condition of the rubber roller is checked.
The process begins with a detailed inspection of the roller. During this stage, we assess the condition of the journals and bearing seats to ensure that the roller has not worn to the point of being unusable. We then check the axiality of the roller and the dimensions of the journals and bearing seats, noting any deviations and irregularities.
If there is serious damage, we recommend repairing or replacing the journals. Please note that shafts with bent or worn journals are subject to much faster wear and tear, which can also lead to machine failure.
Once the inspection is complete, we start removing the worn rubber layer. This is done by cutting until the clean steel or aluminium core is visible on the surface of the roller. Thorough removal of the old coating is important to ensure perfect adhesion of the new layer.
The next step is shot blasting, i.e. cleaning the roller core of any contaminants, rubber residues or corrosion. This process increases the roughness of the surface, improving the adhesion of the new rubber layer.
We then apply a new layer of rubber.
Next, we apply a specialised adhesive to the roller’s surface. The adhesive must be applied evenly to ensure adequate bonding strength.
At Remdruk, we use two-component adhesives that are resistant to high temperatures and mechanical loads. These adhesives cross-link in an autoclave under the influence of high temperature.
We then apply a new layer of rubber to the prepared roller. The rubber compound used depends on the operating conditions and intended use of the roller. It is possible to use rubber compounds with different properties.
- antistatic
- conductive
- insulating
- some are certified for contact with food.
- resistant to high temperatures (silicone).
- resistant to aggressive chemicals.
- hard-wearing with enhanced mechanical properties.
We use the following rubber compounds: NBR, EPDM, CMS (Hypalon), HNBR, Ebonyte and silicone, as well as others on special order.
The raw material is wound from a roll onto a core to avoid air bubbles forming between the rubber layers.
To ensure perfect rubber pressure during vulcanisation, the roller is wrapped with a nylon bandage. This ensures even adhesion of the rubber to the core, removes air from the rubber layers, and eliminates the risk of the rubber ‘flowing out’. We use bandages that are highly resistant to temperature and pressure.
Rubber vulcanisation
The process takes place in an autoclave, where the roller is subjected to high temperatures and pressures for a specified period of time. Under these conditions, the elastomer undergoes a chemical cross-linking process that gives the rubber its final properties, such as elasticity, hardness and resistance to chemicals and mechanical forces.
The rubber roller is then cooled.
After vulcanisation, the roller is cooled under controlled conditions to prevent stress to the elastomer structure. The cooling process is gradual to allow the rubber to maintain stable technical parameters.
After cooling, the roller undergoes preliminary skinning, i.e. rough machining. The excess rubber layer is removed from the surface. This gives the roller a preliminary cylindrical geometry and prepares it for further grinding.
Roller grinding
This gives the roller surface its final smoothness and the correct parameters. Depending on the intended use of the roller, cylindrical or barrel grinding is used.
We can also grind rollers into cone or concave shapes. Rubber rollers can have either a smooth or a grooved surface. Grinding is performed on both conventional and numerically controlled machines.
We specialise in regenerating demanding rollers for varnish, paint and adhesive applications, where precision is essential.
Finally, we carry out detailed quality control, checking all the roller’s dimensions and parameters, such as diameter, rubber roughness and hardness. The finished roller is packaged to ensure safety during transport and protect it from mechanical damage and external conditions.
Why is it worth regenerating rubber rollers?
The condition of rubber rollers should be regularly monitored and, if necessary, they should be regenerated or ground. Regular grinding or regeneration ensures continuity of production and consistent quality of the final product.
Once the rubber coating has been reconditioned, the rollers should be used in the machine for a similar period to that of the original coating. If the rubber compound is chosen correctly, the properties and performance of reconditioned rollers should be the same as those of the original rollers.
It is becoming increasingly rare to purchase new rollers from machine manufacturers. As is well known, the prices charged by service centres and manufacturers for new rollers are significantly higher than the cost of reconditioning a roller at a specialised company. Customers are aware of these high costs and usually opt for reconditioning, which is much cheaper and produces an identical or similar final result to working with rollers from the machine manufacturer.
Summary
Rubber rollers play an important role in industrial processes, and their longevity directly impacts production efficiency and product quality.
Regenerating these components significantly extends their service life. Although roller replacement is inevitable, proper maintenance allows for maximum utilisation of their potential, reduction of operating costs, and increased production efficiency.
If you would like to learn more about our offer or have questions about the regeneration or production of new rollers, please contact us – we will help you find the best solution for your production.
e-mail: remdruk@remdruk.pl / tel.+48 506-172-147
