SKF bearings increase maintenance intervals for Warburtons

Warburtons is a British baking firm founded in 1876 and based in Bolton, Greater Manchester. It remained a thriving family-owned business serving the North West of England until the late 1990s, when increased demand sparked an expansion programme. Warburtons is now one of the best-selling food and beverage brands in the UK, and so any improvements in efficiency within this expanding business will be felt on a large scale.

One area in which Warburtons wanted to increase efficiency was in the ovens at its Enfield site, where oven unloaders transport trays of product on rollers repeatedly throughout the day. The efficient daily repetition of this process depends on the use of resilient bearings that can cope with regular temperatures of up to 120degC (and local temperatures of well over to 200degC if unloader trays jam). In addition, the need for re-lubrication places a heavy burden on maintenance, both in terms of time and expense, since regular re-application with expensive high-temperature greases is required.

Despite the fact that frequent re-lubrication was being carried out, Warburtons had been experiencing a series of bearing failures on their oven unloaders and the maintenance downtime was proving costly. Automatic lubricators had been considered but were not a viable option as, in this application, they would have been prone to frequent failure like the bearings, and so maintenance engineers were required to apply lubrication in hard-to-access points that posed a threat to their safety. With so many problems to address, Warburtons decided to tackle the issue of both the bearing failures and the frequent, expensive re-lubrication. Warburtons needed to try something different; not just a new set of bearings but a different kind of bearing approach.

Dry lubrication

The answer came in the form of SKF extreme temperature Y-bearings (VA228), a dry lubrication option that does not require any re-lubrication. These bearings are fitted with a graphite cage that releases minute amounts of graphite powder to lubricate the bearing, offering an excellent dry lubricant option for low-speed, high-temperature applications such as ovens. For hygiene-sensitive industries such as food and beverage, these bearings offer the significant additional benefit of eliminating the risk of product contamination from grease. This makes SKF extreme temperature Y-bearings a powerful option in a bread oven, minimising product contamination while withstanding temperatures of up to 350degC.

Paul Moodey, Engineering Manager, Warburtons, explains: "The SKF solution brought a number of benefits. As well as cutting unscheduled maintenance to zero on the oven unloader, SKF extreme temperature Y-bearings provided a greaseless solution that removes the need for re-lubrication, which was previously a difficult maintenance activity. The new bearings eliminate the risk of product contamination by grease, are extremely reliable and offer a long service life, reducing standstills and lost production. We have now extended maintenance intervals from 6 months to 3 years and counting."

The reduced costs of work related to repairs, manual lubrication, product or component consumption, and lubricant consumption achieved by installing SKF extreme temperature Y-bearings totals almost 7k per year, while the total benefits of MTBF against costs are expected to deliver a return on investment of 200 per cent.

Further information about SKF extreme temperature Y-bearings can be found at www.skf.com/uk.