Oils And Lubricants-Article

SEPARATING FACT FROM FICTION

Common Lubrication Myths

By Eric Fleischer Mobil Oil Corp., Fairfax, VA

Myth No.1: Oil is oil

Some characteristics differ obviously between oils-for example, viscosity. But other differences are not so obvious. There are hundreds of industrial lubricants, each formulated for specific applications, and each contains additives specially blended for those applications. Using the wrong lubricant is a major cause of lubricant-related machine breakdowns. Using the right lubricant can help improve machine efficiency and extend component life.

Myth No.2: Oil never wears out Oil does not wear out.

The primary enemy of oil life is heat. At operating temperatures of 150 F and higher, oil begins to oxidize and thicken. Sooner or later, depending on oil quality and operating temperature, the oil will leave a trail of sludge and varnish throughout the machine. To prevent sludge and varnish, change the oil every 6 months in machines that operates at high temperatures, and every year in others. Some oil suppliers will take regular oil samples from critical industrial machines, run them through a battery of tests, and provide a report on oil condition. Such reports can pinpoint the right change intervals.

Myth No.3: An oil’s only job is to lubricate:

In many applications, oil must also flush away dirt and wear particles and carry them to the machine’s filters. Oil also dissipates heat. Both oil and grease may help seal bearings to prevent the entry of contaminants.

Myth No.4: If a little oil or grease is good, a lot is better:

Applying too much grease can rapture seals and thus allows contaminants to enter the machine. In an electric motor bearing, the grease can also penetrate the motor windings and cause the motor to burn out. Excessive grease in a bearing can also generate heat because fluid resistance is greater, contributing to a costly bearing failure. Excessive oil can also generate heat because of increased fluid resistance: This heat shortens oil life. Overflowing reservoirs sometimes noticeable only after the machine stops and all oil has returned to the reservoir-can contaminate the process and create unsafe work conditions. Overfilling splash systems can rapture seals.

Myth No.5: The cleaner the oil is, the better the oil is :

In some cases a dirty oil is satisfactory. Internal combustion engines, for example, create large amounts of unburned carbon and other materials that are carried in suspension in the oil until they can be deposited in the filter or the oil can be changed. Here, a dirty oil is probably doing its job. But in hydraulic systems in numerical control machines, even minute amounts of contaminants are intolerable because they quickly clog the servovalves. In short, for some applications the oil should look dirty, and for others, it must be clean. Monitoring oil condition is always advisable.

Myth No.6: Anyone can do the job of lubrication:

In addition to being careful and thorough in following a machine’s lubrication chart, a good oiler knows the machines he works with and will look and listen for problems. He has been trained to check for excessive heat, unusual machine noise, and any abrupt changes in color or odor.

Myth No.7 : Lubrication is a costly headache

Lubrication, when compared to the cost of downtime, is not costly. In plant after plant, machine breakdowns can be traced to half-hearted or unsystematic lubrication practices. When these same plants have tightened their lubrication practices, they have been downtime rates plummet, production increase, and overall operations run more smoothly.

Myth No.8: The cost of lubricants is the highest of all lubrication costs:

The ratio between the cost of the lubricants and the cost of applying the lubricants is usually about 1:5. That is, it costs five times as much as to apply the lubricants (lubricator, supervisor, storage, handling, and dispensing manhours, and equipment) as it does to purchase the lubricants. In some plants, this ratio is much higher.

Myth No.9: A lot of money can be saved by conserving fuel, but conserving lubricants isn’t worth the effort:

By using lubricants best suited to the machines and operating conditions, practicing efficient machine maintenance, filtering or reclaiming lubricants, and when appropriate, lengthening drain intervals, a plant can reduce lubricant consumption dramatically. Often, thousands of dollars can be saved. Consider these two examples. * A manufacturer of metal products reduced its lubricant costs $ 33,000 a year by switching to premium, long life lubricants that do not have to be changed frequently. * A plastic products plant cut hydraulic oil consumption in half when it began reclaiming contaminated hydraulic oil. In addition, oil condition was improved several hundred percent, thereby reducing oil-related downtime, lost production, and machine maintenance costs.

Myth No.10: When it comes to lubrication, nothing is new:

Industrial machines have been getting more powerful and more complicated, and industrial lubrication has had to keep in step with technology. For example, synthetic oils have been developed to meet the simultaneous demands of high-power machines and energy conservation. Today’s lubricants on the basis of performance and using them as long as they are doing their job safely, will help hold down the rising cost of maintenance.