It was seeing failures on cam followers, all-metal roller wheels which provide unpowered linear motion, that transport product through the process. The lines included sticky and messy environments, and so were exposed to high-pressure washdown with caustic solutions. They experienced a high rate of failure in bearings; many were collapsing on a monthly basis.
The time required to perform a repair varied, depending on machine, from four to six hours up to 24. The location of the parts often limited the speed of repair, as technicians might have to strip down machinery or remove the surrounding structure to access the parts. Speed of repair also related to supply of spare parts, and as the operator was expecting failures, it kept supplies on hand.
The existing parts supplier was only too happy to provide replacements and continually turn over the stock. However, from the manufacturer’s point of view, the most efficient way to increase production throughput, is to reduce any potential for downtime. In addition, on-site stores staff will be able to identify the parts currently being specified, but do not necessarily know why particular parts have been chosen or the causes of failure.
As part of its specification service, IKO’s team of technical sales engineers is encouraged to walk the production line, talk to the people running the machinery, take photos, identify the parts of the equipment that are failing, and as a result offer professional observations and opinions on where improvements can be made.
As part of this process, IKO collected some of the failed bearings for inspection and issued the client a detailed report of its professional opinion on the root cause of the failure. After inspection it was apparent that the washdown procedure used to clean the lines was washing away the lubrication. This caused excessive corrosion to the rolling elements, which inevitably led to the collapse of the cage and resulted in rotational seizure and finally total collapse. It is important to understand that the term ‘sealed for life’, when applied to bearings and cam followers, only means for the life of the seal, and this life is impacted by the operating conditions they are subjected to.
To resolve these issues, IKO suggested three interventions: using its solid C-lube technology, or alternatively its centrally-lubricated cam followers and, in some areas, an external C-lube unit to lubricate the cam follower track and mating rolling surfaces.
The C-lube system in the IKO SG line is available for head diameters of between 13-52mm, consists of an FDA-compliant resin impregnated with an NSF H1 certified lubrication oil. This resin deposits a small amount of lubricant on to any dry contact surfaces via capillary action. This ensures that the surface is never over-lubricated and removes the requirement for a regreasing regime. It also protects the internal mechanics because all rolling elements are encased in solid lubricant. Second, for cam followers outside of washdown areas, IKO’s centrally lubricated cam followers were specified. These allow connection to an automatic lubrication system via three different ports, adding extra flexibility to the mounting arrangements.
In total, some 3,000 cam followers were changed during a period of line shutdowns over three to four months.
With these changes implemented, the frequency of planned maintenance was reduced from every month – when they were greased or replaced – and is now incorporated into the annual facility shutdown (where a pre-selected number of cam follower units are replaced). Not only did IKO drastically reduce the maintenance costs, which included grease, shutdown time, loss of production and of course replacement bearing, but also had the added benefit of increased production rates and improved production volumes.
