Paul Dysiewicz, engineering manager at SKF, puts forward the environmental and economic case for the remanufacturing of bearings, and explains the engineering processes, considerations and options involved

‘ W

aste not, want not’ and ‘make do and mend’ may be old adages, but

the sentiments behind them have very modern applications in today’s industry. Remanufacturing of key components not only helps satisfy the growing demand for sustainability, but contributes to maintaining profitability in an increasingly competitive marketplace. Companies wishing to strengthen their

environmental credentials should try, where possible, to avoid simply discarding used bearings and replacing them with brand new components. Through remanufacturing, material waste is reduced and the kind of circular economy on which sustainable industry depends is encouraged. At the same time, fuel resources are conserved, and carbon emissions reduced, because remanufacturing bearings uses up to 90% less energy than producing new ones. As part of a holistic approach that also

includes predictive maintenance, remanufacturing extends a bearing’s service life, maintains its performance efficiency and improves its reliability. It minimises the chances of unplanned downtime due to bearing failure or, worse still, a catastrophic breakdown of vital machinery. Maintenance and repair costs are cut, uptime is increased, and loss of production is avoided. The bottom line is a significantly lower total cost of ownership. Remanufacturing makes most sense for

medium-to-large bearings working in arduous conditions. It is especially suitable for those with an outside diameter of 420mm or more, and for backing, slewing and caster bearings. The caster category includes spherical, cylindrical and CARB toroidal roller bearings. Machines used in heavy industries such

as metals, mining and mineral processing have much to gain from bearing remanufacturing, as do those used in harsh environments. Bearing damage can take the form of

excessive wear, corrosion, indentations or microcracks, often caused by contamination or sporadic metal-to-


SKF offers a range of predictive maintenance and related services which will maximise service life, minimise downtime and help control costs


A combination of bearing remanufacturing and preventative

maintenance is good for both the environment and for business

metal contact in the rolling contact zone. Detecting damage early, before it has progressed too far, enhances the prospects for remanufacturing and lowers the cost. Ideally, detection should be based on the use of condition monitoring technology. Having detected a problem, the bearing

is dismounted and examined to assess the nature and severity of the damage. Measurements including clearance, ovality and variation in wall thickness are taken, followed by further non-destructive testing where appropriate. A thorough analysis is carried out to

determine the feasibility and cost of remanufacturing, taking into account the work needed and the bearing’s size, complexity and price. Also considered are the bearing’s specific application needs, for which a compatible remanufacturing process must be selected from the choices available. In some cases, remanufacturing will not to be economically viable. In others it will achieve savings compared to buying a new bearing. Essentially, remanufacturing replaces

defective functional surfaces and, if necessary, other bearing components. The time taken, and the cost, depends on the bearing’s condition. It can be anything from a few hours to several days. Within this process, there may be opportunities to modify or upgrade the bearing’s specifications. Sensor attachment, application of integrated lubrication and the addition of various seals and coatings are amongst the options. The standards, quality assurance, equipment and processes applied by the remanufacturer should match those of the original manufacturer. Before returning the bearings, SKF’s

standard practice is to mark each one with a unique code and electronically record all data related to it. This makes the unit easily traceable, so its continued lifecycle can be tracked. The value of remanufacturing can be extended by introducing accurate status monitoring of a plant’s machinery and components, to prevent recurrence of similar damage. SKF offers a range of predictive maintenance and related services which will maximise service life, minimise downtime and help control costs. They include corrective action plans based on root-cause analysis of failures. Also available is SKF’s Rotation for Life

programme, which provides an economical, long-term contract benefitting from a single source of specialised bearing services, technology and components. Damage detection, bearing remanufacturing and maintenance of plant reliability are all covered by a monthly fee, payable on meeting agreed performance indicators. Optimisation of the customer’s spare parts inventory adds further savings, with less capital spending and minimal waste.

SKF (U.K.)


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