Most bearing failures occur due to poor installation or maintenance, how can these problems be countered?

Written by: Eureka! | Published:

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.

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.

Within the framework of AIP, NSK can perform on-site inspection of both bearings and operating conditions. Company experts can then make a specific proposal on which bearings to use, supporting their recommendation with a cost analysis.

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 dramatically: 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.

The latest Cloud-capable condition monitoring systems from Schaeffler, such as the Smart QB and the SmartCheck, offer a suitable platform for managing and processing ‘Big Data’. These systems are quick and easy to install and set up, with the user requiring no specific skills or knowledge of vibration diagnosis.

With the Smart QB fixed online monitoring system, when changes occur in the condition of the equipment, the system automatically generates plain text messages on a display, providing the user with clear instructions for action, enabling any corrective maintenance work to be undertaken and any replacement parts to be ordered if required. These ‘automatic fault assessment’ CM systems are groundbreaking, as they do not require specifically trained vibration experts to analyse the data.

With ready-to-use, preset measurement configurations, these systems are helping users identify the main causes of faults, e.g. bearing damage, imbalance and temperature increases. For general changes in vibration patterns that cannot be clearly attributed to one of the above, the system can request, via the cloud, additional analyses from a specialist.

The advantages are that analysis can now be carried out anywhere at any time, with the expert being located anywhere in the world within a company or externally. Similar equipment can be compared across global manufacturing plants, to compare and/or develop trends.

Schaeffler’s components, such as bearings, are used in important parts of plant and machines which produce critical information about conditions and movements. Schaeffler is continuing to invest heavily in research and development and has incorporated sensors, actuators and control units with embedded software into its products, including rolling bearings and linear guidance systems. With these new digitalised, Industry 4.0 technologies, it is now possible for these products to collect and process valuable data on the condition of a machine or process and then convert this data into added-value services.

Schaeffler’s Cloud-capable SmartCheck CM device, for example, allows a simple and flexible point of entry into the digitalisation of machines and equipment based on vibration monitoring.

Components equipped with sensors are central to the drive systems used in machines and equipment – they record data and are the fundamental “enablers” for these digital services. Schaeffler’s aim is to continuously transform conventional mechanical products such as bearings and integrate these into the digital world. This represents an important step towards a future in which not only complex systems but also simple assemblies and machines will have easy access to digitalisation and the Internet of Things (IoT).

The recorded vibration data from bearings can now be transferred via a flexible Schaeffler Gateway to the Schaeffler Cloud, where the company’s rolling bearing domain expertise is made usable in the form of digital services. For example, automated rolling bearing diagnosis and ‘remaining useful life calculations’ can be used to provide precise information on the condition of the bearing and therefore of the machine or process being monitored which in turn, allows specific actions to be recommended. It will even be possible to use actual load data to make adjustments to operational machine processes in real time.

Bearing child safety in mind with igus

As part of its Young Engineers Support (YES) programme, igus supports innovative student projects such as ‘EMKindersicherung’. In Germany, the 94,000 calls made to the Poison Information Centre for burns and intoxications of children every year show that household cleaners constitute a real threat. To prevent these accidents, a team of seven students of TU Darmstadt at the Faculty of Electrical and Information Technology have developed a special child safety lock.

Called EMKindersicherung, the safety device allows personalised access to household chemicals via a smartphone app. It is 3D printed for the most part and consists of a housing that is placed over the lid of the cleaning agent bottle and engages with the cover plate under the plastic ring of the bottle. Using a lever the cover plate can be moved manually and the device can be secured. The closing mechanism consists of an electro-thermal actuator. Its current feed heats and deforms so that the safety device opens and can be removed from the bottle. The actuator is attached to a pin. By turning the lever, the pin mounted with an iglidur plain bearing engages and prevents an unauthorised opening.



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