FEATURE SEALS & BEARINGS
When remanufacturing beats replacement
cement, pulp and paper, and marine.
MAIN BENEFITS There are several potential advantages to remanufacturing, and the most significant one is cost. The work required to repair a damaged bearing is usually far less costly than installing a new one. At the same time, there are also knock-on benefits such as reduced maintenance costs. The remanufacturing process breathes
new life into a bearing, helping to extend operating life beyond its original expected lifespan. Linked to this, the process can also increase the uptime of a production line by boosting asset reliability. Lastly, there is a significant
improvement in sustainability. The energy required to remanufacture a bearing can be as little as 10 per cent of that needed to make a new one.
by Phil Burge, marketing and communications manager, SKF A
damaged bearing does not always need to be replaced – but can
instead be remanufactured, leading to significant cost savings, lifecycle improvement and sustainability benefits. The first stage is to assess the damage to the bearing. This involves visual inspection to determine the extent of the damage and can include parameters such as residual magnetism and clearance. This is followed by non-destructive testing to gain a more detailed picture. The remanufacturer must be
experienced in bearing manufacture, as well as understanding the exact conditions under which the remanufactured bearing will be used, as this will ensure the work carried out is appropriate to the application. This includes taking account of factors such as bearing load, lubrication conditions and the time in
operation.The work required to remanufacture the bearing, along with the cost, will be carefully detailed before any order is placed. Although remanufacturing may be seen
as a ‘slower’ option that straight replacement, as the specific part needs to be disassembled, shipped to the supplier for repair, then shipped back and reinstalled, the process can be relatively quick. For instance, as part of a service contract with paper manufacturer Voith, SKF included fast-track remanufacturing services. Here, if a bearing was deemed
1 NOVEMBER 2018 | FACTORY EQUIPMENT 0
suitable for remanufacture, it was sent to SKF and returned within 10 days. The remanufactured bearing then included a new warranty. In many cases, short lead times like this
can be achieved during normal line shutdowns, which ensures there is no loss in productivity. In some cases, remanufacturing can take just a few hours.
REPAIR SUITABILITY Not all bearings are suitable for remanufacturing. Firstly, those that have suffered heavy damage, fractures or sub- surface initiated fatigue, should simply be replaced because the damage is too serious to repair. However, those that have suffered some form of surface- initiated fatigue can often be restored using honing or grinding. However, many other types of bearings
lend themselves to remanufacturing, as long as the damage is not too serious. These include: • large bearings with an outside diameter of 420mm or more; • backing bearings; • caster bearings, such as spherical roller bearings and CARB bearings; • railway bearing units; • bearing housings; and, • slewing bearings. Overall, the remanufacturing process is
more appropriate for use in heavy industries, such as metals, mining,
A damaged bearing does not always need to be replaced – but can instead be remanufactured, leading to significant cost savings, lifecycle improvement and sustainability benefits
KEEPING TRACK A remanufactured bearing is as unique as one that has just rolled off the production line, and issues such as traceability are equally important. Advanced management processes can
be used to register all the data of each case and can apply a unique code to each asset. In this way each remanufactured bearing can be tracked through its future life cycle. Remanufacturing can also be used to add bearing feature modifications for different or higher specifications, such as mounting sensors, providing integrated lubrication or offering different sealing or coating solutions. Once remanufacturing has been
carried out, it is important to try and avoid the original damage recurring. This can be done by using predictive maintenance to gain information about the ongoing status of plant machinery using techniques such as vibration analysis. In addition, suppliers like SKF can offer root-cause failure analysis to identify the reasons behind bearing damage and come up with a ‘corrective action’ plan to prevent the problems from returning. The tell-tale signs of bearing wear
SKF
www.skf.uk.com T: +44 (0)1582 490 049
can strike fear into the heart of both production and maintenance managers. However, the option of remanufacturing, especially for larger bearings, is a way of returning to as- new condition, as well as being a more sustainable and potentially economical way of extending bearing lifecycle.
/ FACTORYEQUIPMENT
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