"Lubrication is the lifeblood of rotating components," says Ralph Whitley, director of engineering, Boston Gear http://www.bostongear.com, "but it is one of the most overlooked and typically misunderstood failure modes."
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Recent economic pressures have exacerbated the problem. Many plants are stretching equipment service lives while pinching maintenance resources and pressuring purchasing departments to seek the lowest prices at any cost. "Supply-chain optimization has resulted in many plants being forced to use the cheapest lubricants accompanied by severely limited services," says Eric Bevevino, business unit manager, industrial and integrated solutions, ChevronTexaco Global Lubricants http://www.chevrontexaco.com.
The resulting brain and manpower drain has left many facilities with little expertise in or emphasis on lubrication, and even many of the best are not pursuing better practices. "They need to get from straight preventive and predictive practices to reliability-centered maintenance [RCM]," Bevevino says. "Now that supply chain has run its course, that's where the next big savings will come from."
In this environment, careful, comprehensive attention to lubrication is raising reliability and lowering costs, giving some plants a competitive edge.
"The focus is on reliability," says Al Kastonek, predictive maintenance manager, Keewatin Taconite, Keewatin, Minn. "If you're not doing that, then what are you doing? What's the alternative?"
Reliability gets attention
Methods for improving reliability range from hand-written records to the latest predictive technologies, but the key trend is actually doing it. At the high end, more plants are making reliability a job or department function, supported with training, software and authority.
An effective reliability engineering department includes "a cross-trained group of highly skilled technicians whose main focus and function is to keep equipment running at optimal performance continuously," says Mike Holloway, director of technical development and reliability, NCH Corp. http://www.nch.com. Its RCM program uses both predictive maintenance (monitoring vibration, temperature, alignment, wear debris, oil analysis, etc.) and proactive maintenance: monitoring and correcting failing parts, identifying root causes and setting up corrective action plans.
Holloway says the best implementations are taking full advantage of equipment maintenance management software to "not only generate and schedule work orders, but to track equipment repair costs and identify failure modes."
Most plants are still far short. "If they have world-class practices, they have a fairly comprehensive oil analysis program," says Dave Como, U.S. lubricants expertise group, Dow Corning Molykote http://www.dowcorning.com. "Progress will come when they actually take that data -- take that software -- and put it to use. Perhaps 30% are doing that. A lot of them are taking the samples, then changing the oil every six weeks."
Keeping it clean
As a lubricant expert for a tribology company in a former life, Noyan Ercan, reliability engineer for the Shell Co. of Australia http://www.shell.com.au, learned, "You can buy the most expensive lubricants, but if you don't keep them clean, it's all for naught."
But it was the third-shift catastrophic failure of a forced-draft fan that made him a crusader against poor storage and dispensing practices. The fan bearing housing had been topped up using a common metal oil container kept near the blower for that purpose. A post-mortem investigation found the oil in the container included about 50% water. Water in the bearing led to loss of lubrication, metal-to-metal contact, and destruction of the motor as well as the bearing, shaft and seal.
Conventional drums and top-up cans breathe with changes in temperature, collecting condensed steam, rainwater and airborne contaminants, Ercan says. They end up containing a mixture of oil, water, dust and dirt. "Even sealed drums breathe through the bung threads and collect water over time," he says. "You can have a brand-new drum and if it's been sitting around, when you open it and shine a flashlight in, you can see water at the bottom."
Water can also enter equipment directly through seals, vents or breathers. It may come from humidity, rain, temperature changes, steam quenching or washdown. "Humidity sensors can measure the amount of water vapor present in the lubricating oil," says Rojean Thomas, manager of engineering, Trico Mfg. http://www.tricomfg.com. A sensor can be submerged in the oil or mounted above it to measure the relative humidity in the headspace.