Mind Your "P's"
Preventive measures may save you more than just time

by William Hoyt

Did your mom ever tell you to "mind your P's and Q's?" Even if you were never quite sure what P's and Q's were it probably sounded like something that carried a lot of wisdom. Dad usually covered the basics about taking care of things before they break. "Make sure you check the oil next time you get gas," or "Clean and oil that tool before you put it away." Sound familiar? Of course Dad was talking about the basics of preventative maintenance (PM), even if he didn't use that term.

Preventative maintenance has been around for a very long time. If you have ever had the instinct to care for your tools or machines, you have been practicing some form of preventative maintenance. Preventative maintenance remained quite informal until common purchases accompanied an instruction booklet for the use and care of the product.

Emergence of "PM"
In the late 1930s preventative maintenance was recognized as a "system." The advent of World War II solidified its importance. Did PM significantly impact the war's outcome? While there isn't any substantial proof, scores of military maintenance people came out of the war firmly believing that it was the only way to do things. These military people became ex-military and soon began filling jobs in private industry, bringing strong beliefs on how a successful maintenance program should operate.

Preventative maintenance became commonplace in most of the major manufacturing companies in the United States. Written PM's became prevalent for anything as basic as a weekly cleaning and lubricate, to complete rebuilds on an annual calendar. Gradually, PM started to fall out of vogue. Figures from the mid-seventies claim to show that only about 25% of companies were using an effective system of PM. The obvious question is why? The answers are not easy to come by, but one of the theories is based on another P word, profit. 

Program profitability
The maintenance area in a company is not a profit center, it is an expenditure. Spending money reduces profits. This is of course an exaggeration, but with increased pressure to show continually improving profitability, the expense side of the ledger receives more scrutiny. One of the problems that PM encountered was a lack of data that was able to translate the positive impact of PM to the bottom line. Most companies realize that a good PM program can have a substantial positive impact on profitability by doing the following: 

• Increasing equipment uptime
• Reducing the cost of the equipment over its life
• Maintaining and improving product quality
• Decreasing rejects which reduces rework
• Reducing overtime
• Lowering the frequency of maintenance requests 

Most companies have some type of preventative maintenance program in place, even if it is as basic as a schedule for waxing and greasing the ironers, to oiling the washers. Few companies do it right. The beauty of PM is that it is inexpensive. PM usually costs less than half of what breakdown maintenance costs. For PM to be effective, it needs a strong commitment from management, and also has to be well organized to be cost effective. 

A critical focus
Most plants won't have the luxury of dedicating one maintenance engineer to only performing PM, but proper training for performing assigned PM tasks is crucial. Another crucial aspect of PM is following predetermined schedules and checklists for all PM work. If PM work is going to be disruptive to production, go over the schedules with production people so they can plan accordingly. Another killer to a quality PM program is breakdown work that preempts PM. If PM schedules fall behind, the plant can easily fall into a difficult circular dilemma-less PM means more breakdown maintenance, which takes away time from PM, which increases the likelihood of breakdowns. It may be that the only way to break that kind of cycle is to dedicate one person, if only on a temporary basis, to doing only PM. 

One of the key elements to a quality preventative maintenance program is maintaining an equipment history. Like the overall PM program, many companies practice it, but don't really do it well. A very typical equipment history might be keeping a file folder with work orders and purchase orders that are updated only when someone has the spare time, or when some spare help is available. Good equipment history, whether kept manually or in electronic files, will tell management a lot. It can justify equipment replacement or complete overhaul. It is difficult and foolhardy to make equipment decisions based on gut feeling about a machine being down too much, or getting another couple of years out of it. Without proper equipment history, you may be spending three times more in annual repair and maintenance on a machine, than it would have cost to replace it and not realize it. 

From words to action
Designing and implementing a PM program is neither as difficult as some say or as easy as others claim. Its effect may change the culture of your engineering department from being heroes for fixing something to being heroes for everything working. A good PM program requires at a minimum: management commitment, checklists and procedures, schedules, reports, equipment history reporting and analysis, and training.

Another "P"
When you have implemented your preventative maintenance program and are comfortable that it is performing to expectations, then you are ready to look at the next "P" in maintenance, predictive maintenance (PDM). Predictive maintenance is defined as the use of graphic trends of measured physical parameters against a known engineering limit for detecting, analyzing, and correcting equipment problems before failure. Basically, if you can't prevent it, predict it. Predict sounds like the guy saying that one team is better than the other, so they will win by a touchdown. In fact, predictive maintenance needs to be combined with a solid preventative maintenance program for it to be effective. 

"P's" into practice
Many machines in a commercial laundry have some type of monitoring equipment or gauges that are already in use or at a minimum installed. Think about thermostats, pressure gauges, water level gauges and you start to get the idea. There are other areas that can be measured or monitored for things such as vibration velocities, tension, pressure, alignment, wear, heat, resistance, capacitance, etc. that can be used to predict imminent problems. If PM and PDM are used to supplement each other, maintenance costs will be reduced even more than with just a PM in place. 

Predictive maintenance is typically targeted at critical equipment that, if in a failure mode, would interrupt or stop production, substantially effect energy costs, or inhibit safety or pollution control. PDM is generally considered to cost less than PM and breakdown maintenance combined.

Preventative and predictive maintenance sound similar, and in some ways they are. One way to explain the difference is to say that you need to check the oil levels on your machine and replenish it on a regular schedule. That is PM. PDM is reviewing the reports and realizing that you are using too much oil. Effective PM and PDM programs complement each other. Neither will provide 100% up-time, but the effective use of both will help you take great strides in reducing unplanned downtime.

Chances are, the Engineering/Maintenance Department will never be considered a profit center. If a plant utilizes both of the "P's"-preventative and predictive maintenance-and properly coordinates them with a third "P" for production, they will all help improve the most important "P"-profit.

William R. Hoyt is TRSA's director of production operations. Contact him at 202/833-6395 or e-mail whoyt@trsa.org.