In addition, as bearing technology accelerates, opportunities for technology transfer mean that bearings can play a wider role in reducing the whole life costs of machines. This is achieved by applying the latest materials, sealing and lubrication technology to improve the machine design and reduce its maintenance costs.
As a supplier to food and beverage companies, NSK has designed and manufactured a range of bearings, the Spacea series, which is intended to help beverage equipment OEMs and equipment users to achieve all the above objectives; solving problems, improving performance and enabling continuous improvement into the future.
The Spacea series of bearings provides high performance and reliability under all types of demanding operating conditions: corrosive, super-clean, high/low temperature, high speed vacuum and non- magnetic.
The bearings meet the widest range of technical requirements with a programme of high performance materials, surface finishes and specially developed lubricants, including solid types.
To enable customers to meet the demands of a broad range of applications in water, alkali and strong acid environments, NSK has developed the Aqua-Bearing, a special highly corrosion resistant bearing for light load applications in the operating temperature range up to 40°C.
The use of a special fluorine plastic for the inner and outer rings and a fluorine plastic cage, enables the Aqua-Bearing to achieve corrosion resistance equal to ceramic bearings and better than that of previous generations of plastic rolling bearings made of PE (Polyethylene) or PPS (Polyphenylene Sulphide).
The effectiveness of NSK's materials specification means that the Aqua-Bearing is even able to handle applications in strong acids or alkalis, ozonised water, various kinds of vapour and halogen gases.
In addition to providing improved corrosion resistance, the fibre- reinforced fluorine material gives the inner and outer bearing rings increased strength and rigidity.
It also provides an endurance life of more than 1000 times that of A1S144OC stainless steel bearings and five times that of previous PE (Polyethylene) bearings under a light load in an acid solution.
For operations in corrosive environments where higher temperatures are encountered (up to 200°C) NSK has developed Spacea bearings with (nickel coated) inner and outer rings of Martensitic stainless steel, ceramic balls and fluororesin cages.
These bearings are grease free, employing a solid high performance fluorine solid lubricant. They offer higher corrosion resistance than stainless steel bearings, and have longer operating life than hybrid bearings and stainless steel bearings in acid solutions: four times as long for hybrid types, and twelve times that of stainless steel units, when tested in a NaClsolution.
Here the problem is more lubricant than material based, NSK offers its stainless steel range of Molded Oil bearings. These units employ a special solid lubricant to transform the performance of machinery and equipment, in terms of reliability, maintenance free intervals and operation, in environments exposed to high humidity, corrosion and contamination.
The effectiveness of Molded Oil technology enables machine builders to make real cost savings by replacing existing, and often costly, methods of lubricating machine parts.
In real world tests, Molded Oil offers more than twice the operating life of grease lubrication in water contaminated environments. In addition, the technology means that operating environments are kept free of grease; and there is no need for refilling of lubricant, as Molded Oil provides a continuous supply of lubricating oil.
The benefits of Molded Oil technology also extend to beverage applications where manufacturers want to employ the prefabricated advantages of ball bearing units. The bearing units: pillow block, flange and take-up types, are manufactured from stainless steel. They are suited to applications where cleanliness and a high resistance to corrosion are required.
In addition to Molded Oil lubrication, customers for the bearings have the option of a special USDA H1-compliant, food grade grease.
Offering a lower cost option in applications where frequent wash-downs are required is NSK's Silver-Lube range of ball bearing units. These are a range of corrosion resistant mounted bearing units designed specially for use in industries where hygiene considerations and corrosion and chemical resistance are important; typically bottling and brewing, food processing, pharmaceuticals, fisheries and chemical processing.
Silver-Lube housings - pillow block, two and four bolt flange types - are manufactured from PBT. This is a high quality glass filled thermoplastic polyester resin, which has excellent strength, stiffness, dimensional stability and chemical resistance.
Integrated into the housings are bearing inserts with stainless steel raceways, cage, balls and grub screws. The inserts are charged with a food industry approved grease, and are easily regreaseable via a stainless steel grease nipple in the housing. They are protected against contamination by a stainless steel flinger and seal arrangement.
NSK's Molded Oil bearings are also being used to cut maintenance intervals, and deliver extended periods of bearing reliability on a new beefburger-packaging machine, which has been custom designed by Autowrappers for Unilever-Birds Eye Foods.
The Molded Oil bearings are also expected to reduce the total cost of ownership of the new machine, by removing the downtime associated with relubrication intervals, and by cost savings achieved through reduced requirements for replacement bearings and bearing lubricants.
The new Unilever machine is the latest in a long line designed and manufactured by Autowrappers for food packaging applications. The company regularly supplies equipment ranging from a stand alone machines for low speed, hand- fed applications to fully automatic integrated systems that match the exacting demands of high volume fast moving consumer goods (fmcg) and food processing and packaging lines.
The problems of supplying machines for food processing applications are well known, one of the most prevalent being the frequent washdowns that machines are subjected to, to ensure high levels of hygiene. To protect against this procedure, most machines used for food processing are fabricated from stainless steel.
However, components such as bearings are not so easy to protect; a fact that made Autowrappers and Birds Eye look for an alternative on the beefburger machine.
The problem they were looking to solve concerned the tendency of lubricant to be flushed out of conventional bearings under repeated washdowns. The loss of lubricant is usually progressive rather than immediate, but the result is inevitably the same: premature failure of the bearing or bearings concerned. In the pressurised world of food processing, any downtime - planned or not - is costly, so any new design innovations that could overcome the problem are particularly welcome.
Replacing conventional lubricants
NSK's Molded Oil is one such innovation. A plastic composite material containing abundant lubricating oil (or grease), Molded Oil is a replacement for conventional lubricants.
Differing from other marketed oil impregnated plastics, where the oil content is a mere few percent by weight, Molded Oil permits a lubricating oil content of more than 50 per cent by weight.
NSK Bearings equipped with Molded-Oil are environmentally friendly, 'fit and forget' units that are designed to enhance the performance of machinery and equipment in all types of environments, especially those exposed to contamination such as water or dust. Importantly, they address the problem of loss of lubricant due to water ingress, a feature of particular importance on machines used in food processing, as it provides the benefits of increased reliability and longer maintenance free intervals.
NSK introduced Molded Oil to Unilever- Birds Eye during a visit with its local distributor. The response from Unilever's new product/improvement engineers was extremely positive, resulting in the specification of the bearings - sealed deep-groove ball bearings and sealed inserts mounted in Silver Lube corrosion-resistant housings - on the new machine.
To facilitate this process, NSK arranged for a senior application engineer to visit Autowrappers, and offer advice and technical support on all aspects of Molded Oil technology.
"The solution that we have provided to Unilver/Autowrappers clearly demonstrates the benefits of working with recognised bearing suppliers and authorised distributors," said Simon Grant, NSK's Aftermarket Business Development Manager.
"The engineering support provided by NSK, together with access to the latest technological bearing products, is a package that is simply not available from smaller bearing manufacturers and independent distributors. In addition, by supplying an innovative bearing solution, NSK have provided a value-added service to the customer, solving his problem and helping to reduce the cost of ownership on a what is considerable machine investment."
- NSK UK Ltd is based in Newark, Nottinghamshire, UK. www.eu.nsk.com