- Buyer's Guide
“A watched pot never boils.”
- Elizabeth Gaskell
Recently, as I was watching a pot filled with water and potatoes come to a boil prior to a grand holiday feast, my mind wandered to the old proverb “a watched pot never boils.” There are numerous scientific variables that influence the time it takes for water to boil, including the pot’s size and materials, the volume of water, the ambient temperature and atmospheric pressure in which the pot resides, the heat source, etc., . . . watching is not among them. The proverb, of course, is figurative, not literal, and espouses the virtue of patience. The proverb’s origins have been traced to Elizabeth Gaskell’s book “Mary Barton,” published in 1848.
An underlying assumption of the proverb is that it is a good thing for the water in the pot to boil. In the world of machinery reliability and maintenance, this is usually not the case. In fact, most maintenance managers want to prevent situations from reaching the boiling point. Applying a little inverse logic, however, one can spin the same proverb into advice to keep a close watch on things in an attempt to prevent them from reaching the boiling point, so to say. Lubrication surely qualifies as one of those areas where we want to keep things under control. Watching lubrication closely helps to achieve this goal.
Mechanics and/or operators regularly walk-down machines. In most cases, the equipment is looked over every day, every shift in some instances. What a wonderful opportunity to verify that machinery lubrication is OK. However, except for the obvious things like checking the level indicator, it is rare to find the lubrication system on the inspection list. Many variables can be quickly and easily monitored with a small time commitment. These inspection items can be revealing, and will serve as the foundation of a precision lubrication management program.
I have found that keeping lubrication inspection routes simple produces the best results. This is especially true if routes are completed by staff members who possess only a basic knowledge about machinery lubrication. In fact, I like to design lubrication inspection routes comprised almost entirely of questions that the inspector can answer “yes” or “no,” or as “OK” or “not OK.” This keeps the process fast and simple. After all, the primary purpose for performing the routine inspections is to uncover possible problems that require further investigation.
Every plant, and for that matter every machine, will require a slightly different inspection routine and frequency. I have outlined six items to consider when setting up an inspection program.
1. Frequency - No, not all machines in the plant are created equal. Some are highly critical and should be inspected on a regular basis, in some cases every shift or every day. Others require only weekly, biweekly or monthly inspection. Because the lubrication inspection process is simple, err on the conservative side and inspect the machines frequently. The program can always be adjusted later. Consider the machine’s tendency to fail, its impact on production and the cost, time and difficulty of restoring it upon failure when deciding upon your inspection frequency. Too often, the sump volume is the primary determining factor. Sump volume is an easy way to group machines, but the cost of the lubricant is usually the least of your concerns. Use a more thoughtful approach.
2. Observed Parameters - For many machines, the number of observable parameters can reach the hundreds, even thousands in some cases. Obviously some priorities must be established. Select inspection parameters based upon their relative importance. How will an aberration affect the machine’s performance? How frequently do problems detectable with a given inspection occur? For a detailed discussion about various inspection parameters, refer to Noria’s publication “The Lubrication Field Test and Inspection Guide.”
3. Training - Those performing the inspections must have some understanding about machinery lubrication, contamination control, etc. They needn’t necessarily be experts in the area if they have experts to turn to, but they do need a basic understanding. They also require task-based training on performing the inspection. For example, they must know that desiccant is deemed failed when it turns from blue to pink. Machinery lubrication will be new to many of the people performing the inspections. Don’t hold the team accountable unless they have been properly qualified to do the job.
4. Collection Method - The trusty 3” X 5” index card will work for performing inspections, but this requires the individual to remember the inspection criteria or refer to an inspection list, and make notes about his observations. A clipboard with a predefined set of questions (that can be answered yes or no) for each machine is a definite improvement on the index card method. Be sure to leave a space for comments. Both the index card and and clipboard approach require manual entry of the data once it is collected. A more modern approach is to set up the inspection in an industrial-grade personal digital assistant (PDA). For each machine, the inspector can answer yes or no, and as required, write short comments. The data can then be uploaded to a host computer for storage. This speeds the process, assures that the data will be captured and reduces transposition errors.
5. Information Management - Be sure to track inspection findings carefully. Software is the best way to do this, and I have found it is best to keep inspection data where other machine condition information is kept to facilitate diagnostics and failure root cause analysis. Tracking the data also helps identify frequently recurring problems, or lubrication “bad actors.” It also helps optimize inspection frequency. It may be necessary to assign a number to the nominal (yes or no) data collected to conform to the requirements of the software used. Usually, zero and one can be used. Some questions will be answered yes if things are OK, others will be answered no if things are OK. I like to consistently assign zero to the OK condition to simplify graphical trending. A scale of one to three or one to five could also be used. It really doesn’t matter as long as it is simple and consistent.
6. Next Steps - It seems that anytime a problem is encountered with any part of the lubrication system, an oil change is immediately scheduled, assuming this will solve the problem. This is lazy lubrication maintenance - try to drop this habit. Indeed, in many cases the oil must be changed as a part of a complete and cohesive corrective action. In many cases, however, an oil change is not required. Investigate the problem, identify its root cause and implement a thoughtful corrective action that addresses the problems and eliminates any unnecessary steps.
Ineffective lubrication remains one of the leading causes for machinery failure, and in most cases, it is the leading cause by a large margin. Routine inspection of the machine’s lubrication system is among the easiest and most productive ways to avoid equipment failure, and should play a pivotal role in the pursuit of precision lubrication. A positive externality of this program is that operators and mechanics who perform the routine inspections will have new awareness of the importance of effective lubrication, and quality with which lubrication is applied is bound to improve across the board.
That’s my viewpoint. As always, I am interested in yours.