Viewpoint: think before you opt to replace large rolling bearings

Large rolling bearings often play a critical role in keeping high value production plant operating continuously and efficiently around the clock.

Bearings are still often dismounted and replaced as part of a company’s routine maintenance activities, particularly on machinery that is deemed vital to the production process. This occurs in applications such as paper mills, steel and aluminium processing, mining and quarrying, rail and marine.

In many cases though, bearings can be restored to a completely acceptable, functionally reliable condition using appropriate cleaning and rework techniques that save valuable time and money.

You don’t always need to approach the original manufacturer of the bearing. Some suppliers can provide reconditioning services for any product, regardless of the manufacturer. If you already have a good working relationship in place with a particular bearing supplier, it is worth asking them.

Fraction of the cost

Reconditioning or maintenance costs of a large rolling bearing range from 15-70% of the cost of a new one, depending on the work involved. Average costs are around 50% of new purchases.

Reconditioning or maintenance costs of a large rolling bearing range from 15-70% of the cost of a new one, depending on the work involved.

Schaeffler’s service normally involves an initial, free on-site inspection in order to determine whether reconditioning is appropriate – saving unnecessary transportation and inspection costs to the customer.

Guidance can be offered on how the life of the bearings can be extended in the future. For example, by using advanced materials or coatings on certain bearing components.

Visual inspection by trained, experienced engineers can also pinpoint factors that may be causing the bearings to wear prematurely, such as incorrect bearing mounting, inappropriate lubrication or loading conditions.

The expert from one of Schaeffler’s local technology centres will typically photograph the damage, sending the image to specialists at the company’s Wuppertal repair centre in Germany. A costing is provided to the customer, who can decide whether to proceed with an in-depth damage diagnosis and reconditioning work.

The reconditioning process

Reconditioning can be applied to all types of rolling bearings, including back-up rollers, radial spherical roller bearings, cylindrical roller and tapered roller bearings.

The process comprises appropriate cleaning and disassembly, preparation of comprehensive examination reports, including appropriate repair recommendations, and reconditioning proposals.

In many cases bearings can be restored to a completely acceptable, functionally reliable condition using appropriate cleaning and rework techniques that save valuable time and money

These range from simple polishing repairs, through grinding and replacement of individual components, to the substitution of a complete inner or outer ring. Predicted costs and the anticipated duration of repair are calculated.

If certain components cannot be repaired, they are completely replaced. Repaired rolling bearings provide the same performance as new ones.

Other services

In addition to reconditioning, rolling bearings can also be modified and a rolling bearing from replacement parts stock that is no longer required can be adapted to suit a different purpose.

Coatings can also be applied to prevent corrosion, reduce wear or contribute to energy efficiency by decreasing friction. Also, if damage is discovered, a request can be submitted for examination and assessment

Opting for reconditioning of rolling bearings allows companies to contribute to reducing energy consumption and resources. In the case of defective components, Schaeffler ensures correct separation of materials according to grade.

• Dave Wall is senior applications engineer at Schaeffler UK