Bearings are highly stressed drive components which, over a period of time, become susceptible to wear. With this in mind, it is particularly important to include bearings when developing a maintenance plan, as this strategy will help extend the operating life of machinery or equipment.
Ignoring this factor can have major consequences. For instance, the failure of just a single bearing can often cause the stoppage of entire manufacturing systems or production lines. Different approaches to best practice bearing care are summarised by NSK as part of its AIP Added Value Programme.
With up to 20 per cent of all bearing issues caused by incorrect installation, maintenance staff should first be properly trained and, secondly, use the right tools. For this reason, NSK provides training courses for customer maintenance departments. With the maintenance and service package AIP+, NSK offers high-quality, workable tools for facilitating the typical bearing tasks found in industry. The AIP+ portfolio includes mechanical and hydraulic assembly tools, as well as induction heaters.
If bearings have a tendency to fail while machines are in mid-operation, it is often because the optimal bearing type was not selected, or they have not been correctly adapted to the application and/or environmental conditions. Typical examples are machines that need frequent cleaning, such as those in the food processing sector. Cleaning with jets of high-pressure water or steam causes grease to be flushed out, and contamination to penetrate the bearings. However, these problems can be overcome by using NSK’s Molded-Oil bearings, which have the grease durably incorporated in a carrier medium.
Within the framework of AIP, NSK can perform on-site inspection of both bearings and operating conditions. Company experts then make a specific proposal on which bearings to use, supporting their recommendation with a cost analysis.
Reduced bearing failures
A case in point can be seen at a German automotive manufacturer, where motor spindle bearings frequently required replacement in 15 identical production centres. NSK discovered that the premature failures were caused by external contamination and suggested using sealed high-precision bearings. As a result, bearing failures were reduced: service life increased from 12 months to more than 36, which in turn delivered annual savings of slightly more than €50,000 in installation costs alone.
As an alternative strategy, condition monitoring represents a more preventative approach to prolonging the service life of bearings. NSK also offers this service within the framework of AIP+, whereby a company service technician first visits the site to record parameters such as vibration, temperature and the speed of machine components. Then, using a specially developed measurement technique, the technician records and analyses the data with the help of powerful software in line with a standardised procedure. The customer is provided with a comprehensive CMS report that includes a description of the current state of the bearing. Any shaft alignment or adjustment errors, insufficient lubrication, or any premature wear in the drive components, are also highlighted in the report. In practice, this not only acts as preventive maintenance, but makes it possible to optimise the bearings with the goal of extending their service life, largely because any problems can be addressed as soon as they are detected.
In another example, a manufacturer of rolled metal products was experiencing variations in output during slab production. The required maintenance work resulted in reduced production time and greater costs. NSK identified the cause in the drives of the main oven fan and introduced regular CMS inspections at shorter intervals. Predictive maintenance made it possible to establish a time-optimised replacement rota for the bearings that allows the user to save approximately €70,000 per year.
In summary, maintenance engineers have many possibilities at their disposal for increasing the lifespan of bearings. Experts from NSK support both machine manufacturers and users with various services and reliable technical solutions.
Go to www.nskeurope.com for further information.