Every overhead crane depends upon the strength and durability of wire rope for its operation, and like any other machinery part, wire rope must be maintained. Neglected or poorly-maintained wire rope will experience a needlessly-short lifespan and add to the operational expense for users who must replace it. Worse, wire rope that hasn't been maintained is prone to catastrophic failure and could be the cause of serious injuries or death for workers.
Below is more information on maintaining wire rope, primarily through the effective use of lubrication.
Why wire rope requires lubrication
Most individuals recognize that wire rope, being crafted from strands of ferrous metals, is vulnerable to corrosion. Lubrication is an inexpensive, easily-applied solution for preventing wire rope from rusting. However, what is often not obvious to workers is that wire rope is a mechanical device.
The typical wire rope used for overhead crane operations consists of dozens of strands of wires in various diameters, and they are arranged in a variety of complex patterns. Engineers design wire rope so strands bend, slide and mesh in predictable ways to accomplish particular jobs; these intricate relationships will only succeed in working if friction isn't permitted to interfere. Lubrication plays an integral role in ensuring that wire rope can function as intended by removing the harmful effects of friction.
Wire rope lubricant categories
An all-encompassing program for lubricating wire ropes requires that the above needs be met when using lubricants. No single lubricant is ideal for providing the protection from corrosion needed for the surface of wire rope as well as also reducing internal friction. Therefore, lubricants are divided into these categories:
- Coatings—Coating lubricants are used to provide corrosion protection. Their ability to reduce internal friction is a secondary concern, and coating lubricants cannot substitute in this area. However, protection against external friction is of importance and should be factored into the decision-making process. The ideal coating lubricant is resilient to environmental forces, not easily washed from the surface of the wire rope and is inexpensive.
- Penetrants—This class of lubricants is designed to move past the external layer and reach the internal core of the wire rope. To do so, a readily-evaporated liquid vehicle such as a petroleum distillate, carries the lubricant itself through the spaces between the wire and dispenses it to where friction is apt to be present. Penetrants typically have little protective ability against corrosion and should not be used for this purpose.
Considerations regarding wire rope lubrication
To effectively handle the specific lubrication needs of your wire rope, the following considerations will help ensure you are on the right track:
1. Use lubricants specifically-approved for your wire rope—The first resource to consult when obtaining information about lubricating your wire rope is the manufacturer. They can provide specific recommendations about appropriate coating and penetrating lubricants that will best match the specific alloys that comprise your rope.
2. Create a lubrication schedule that is customized to meet your needs—Since not all wire ropes are the same in composition or diameter, and since overhead cranes are used in both outdoor and indoor settings, it is impossible for a one-size, fits-all approach to work when deciding when to lubricate wire rope.
For example, if your operations involve working close to the seacoast, then obviously the corrosive effects of salt will require an enhanced program of lubrication. In general, lubricants should always be visible to the naked eye in the form of a sheen; a dried wire rope is one that requires lubricating. Beyond that specific observation, consult with the manufacturer and engineering staff if you are concerned about how often to lubricate your wire rope.
3. Do not rely on lubrication alone—No matter how effective a given lubricant may be, it cannot substitute for other aspects as they relate to the proper care of wire rope. For example, wire rope should be kept clean through the use of cleaning with brushes and solvents, if necessary. Dirt will adhere to lubricants and lessen their effectiveness. Do not store wire rope in damp locations or in other areas where it is exposed to corrosion-inducing factors.
4. Know when and where to apply lubricants—Since wire rope isn't static but is dynamic as it proceeds through its usage cycle, there are certain intervals when it is advantageous to apply lubricants. For overhead cranes, applying penetrating lubricants as the wire is flattened and slightly opened on the drum is helpful in ensuring core penetration. For coating lubricants, application is best when the entire circumference of the wire rope can be reached and coated at one time.
Learn more about your options by contacting companies like Wazee Crane.