What Constitutes World-Class Reliability and Maintenance? (part 4)
by Christer Idhammar
Note: This column is a continuation of the January, February, and March P&P maintenance columns by Christer Idhammar. In these columns, Mr. Idhammar asked readers to evaluate how well their mills had implemented the systems and practices required to become a "world-class" facility.
In this column, I continue discussing the systems and practices that indicate to me that a mill is "world class." To evaluate how far your mill has to go to achieve this designation, I would suggest reading this column with a group of operations and maintenance employees that includes both management and craftspeople.
On a scale of zero to ten, rate your mill's use of the following systems and practices, with ten meaning that you are so good that it would probably not pay off to do more improvements in this area. A five indicates that you feel you do a good job, while a zero means that your performance is a disaster.
15. The very basics of maintenance are instituted. I have mentioned many times before in this series of columns that the only major difference between the best performers and others is that the best performers implement what others only talk about.
Best performers continuously work on improving the very basics of maintenance while others often overlook them. Some of the maintenance basics that I will discuss in this column include:
- Detailed cleaning of components
- Operations practices.
CLEANING OF COMPONENTS. Detailed cleaning of components and equipment is often a “no man’s land,” because everybody agrees that it is important, but nobody wants to do it. In a world-class reliability and maintenance organization, components and equipment are cleaned in detail. Such an organization realizes that good inspections cannot be done without this level of cleaning and that cleaning also extends the life of components. For example, the life of electric motors (electric life) varies between five months for a dirty motor and over 20 years for a clean motor.
LUBRICATION. Best performers also work on continuously improving lubrication. Their lubricators—because they do believe they need skilled lubricators—are trained in component wear criteria and required lubrication.
Good lubrication must include such work as improving the choice of lubricant, method of lubrication, filtration of oil, cooling systems, prevention of water content, and removal of water content. There are many examples of how this work results in significant life extension, lower lubrication costs, and increased production throughput.
ALIGNMENT AND BALANCING. Best performers have, and adhere to, alignment standards of, for example, 0.002 in. or less parallel misalignment for an 8-in. to 10-in. diameter coupling running at 1,500 rpm in most installations. Precision alignment and balancing of rotary assemblies results in reduced levels of vibration, longer component life, lower costs, and increased equipment reliability. On average, a world-class value is 0.1 in./sec or lower. Several experts in this area have shown a strong correlation between low vibration level and high reliability and increased production throughput.
FILTRATION. Another maintenance basic is filtration of hydraulic fluids, lubrication systems, and seal water for mechanical seals. In most cases, standard filters are not good enough. If you use filters that filter out particles smaller than 5 microns (0.0002 in.), you will have much fewer problems with leaking hydraulics, bearings, and mechanical seals. For example, hydraulics will not leak, bearing life will be extended by up to four times, and the average life of mechanical seals will be over eight years.
OPERATIONS PRACTICES. Best performers teach the operators essential care and inspection of components and equipment. This includes how to start up and shut down processes and equipment without causing any damage. In many mills, it is not uncommon that equipment fails because a steam system was started up too fast, causing equipment failures because of water hammer and thermal stresses, mechanical seal failure because pumps were started up before seal water was turned on to the seals, and so forth.