Archive | March, 2008

9953

6:00 am
March 1, 2008
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Lubrication Of Electric Motor Bearings

Bearing failure or proper lubrication? The choice is yours.

Better lubrication practices could prevent the type of bearing damage that leads to costly premature motor failures in countless plants. How are you taking care of these crucial activities in your operations?

Proper lubrication of ball and roller bearings in electric motors is essential to their health. Grease reduces friction and protects the surface finish from rust during long idle periods and in unfavorable environmental conditions. It also transfers heat from the bearing and even helps protect the bearing from dirt and contaminants. Since bearing life—and, by extension, motor life—depends on proper lubrication, it’s important to use the right grease for the application and to re-lubricate bearings at the correct intervals.

The basics
Grease is a “dirt magnet,” so it’s surprising to many that packing it into the cavity around the bearing actually helps keep dirt and other contaminants from getting into this critical component.

On very old motors, lubrication was provided by oil-soaked felt that “wicked” oil to the bearings. Grease serves this function in today’s machines. Consisting of oil suspended in a base material like lithium, calcium or polyurea, it lubricates the bearing continuously while preventing the oil from leaching out. Depending on its composition, different greases may be better suited for one application than another. For example, one may be superior at high or low temperatures, another impervious to water, while still others retain oil better under extreme pressures.

The lesson here is to select the right grease for the application. An electric motor in an Arizona open-pit copper mine where the ambient temperature is 130 F requires different grease than an identical motor in the Arctic Circle.

0308_lubrication_tab11Of course, it’s sometimes necessary to meet one stringent requirement at the expense of others. In the food process industry, for instance, the most important property of lubricants is that they won’t poison you if they somehow get into the can of beans you’re going to eat for supper.

Compatibility issues
An old professor of Texas history used to say, “Never mix gunpowder and alcohol, ’cause you can’t shoot it, and it tastes terrible!” Although it’s usually okay to combine lithium- and calcium-based greases, mixing lithium- and polyurea-based greases causes the oil to leach out much more quickly than normal, potentially starving the bearing of lubrication. Be sure you know which types of grease your plant uses—and know which ones are compatible with one another.

Table I provides general guidelines for grease compatibility, based on the variances in compatibility of different greases tested by the National Lubricating Grease Institute (NLGI), April 1983. Grease manufacturers often can provide similar charts.

Although compatibility guidelines are helpful, there are enough exceptions to warrant care. Before mixing two greases, check with both manufacturers. If both say it is all right to mix those specific greases, it probably is safe to do so. If either of them says no, don’t risk it (see Fig. 1). Note that in some instances both manufacturers may say it is safe to mix specific greases that are incompatible according to the general guidelines in Table I.

0308_lubrication_fig11Types of grease in motor bearings
Some motor manufacturers have used polyurea-based grease—which performs well at high temperatures (over 250 F) and high speeds (10,000 rpm or higher)—almost exclusively for more than 30 years. Recently, though, several of them have switched to a second-generation polyurea grease that reportedly has even better properties than the old standby. Because these manufacturers produce tens of thousands of motors weekly, their decision to change grease is significant. Such a move indicates a high confidence level in that grease.

Bearing manufacturers, on the other hand, use various greases, depending on application requirements. As a result, the replacement bearings you buy from your local bearing supplier might not contain grease that is compatible with what you use in your plant. So, be careful.

Lubrication intervals
Ultrasonic listening equipment, vibration analysis and thermography all can help predict bearing failures. But according to some sources, an operator tends to grease a bearing only when it “gets noisy enough that he can hear it” over the ambient sound of surrounding equipment. By that time, the damage has been done. Pumping in a few ounces of grease may mask the noise for a while, but it is too late to save the bearing.

Assuming you have a good predictive maintenance program and want to improve on preventive maintenance, how often should you grease the bearings in an electric motor? If you read the manuals for a dozen different electric motors, you’ll likely find 12 different recommendations.

Some of the factors that determine how often a bearing should be greased are:

  • Operating hours
  • Operating temperature
  • RPM
  • Bearing size
  • Bearing type (ball or roller)
  • Cleanliness of environment
  • Vibration levels
  • Criticality of operation

One of the best charts for determining lubrication intervals is based on the bearing bore diameter, rpm, yearly operating hours and type (ball, roller, thrust, etc.). Unfortunately, this chart is not very practical. That’s because the person responsible for greasing the bearings usually doesn’t know the bearing sizes of every motor, and some motors have a different bearing size on each end.

Another drawback of this method is that each motor in a plant probably will have a different lubrication schedule—motors could be installed at different times, they could operate a different number of hours/year, their usage could vary with the seasons. It’s easy to see why something that sounds simple (e.g., “Grease the bearing every 4000 operating hours with 1.0 ounces of fresh grease”) may be hard to implement.

Various industries have tried to simplify the task by developing practical guidelines like those in Table II. Each represents a compromise, though, so none of them works for every situation.

One thing that bearings and motor windings have in common is the 10-degree rule. Every 10 C degree increase in temperature cuts their life expectancy in half. If a blanket of grease raises the winding temperature 20 C degrees, the winding will last only one-fourth as long as it should have. With an increase of 50 C degrees, a winding that should last 20 years would have a life expectancy of only about eight months. Unless you really enjoy changing motors in the middle of the night, try not to do anything that increases the motor temperature!

Lubrication procedure
Now we come to the recommended procedure for greasing bearings. Under normal conditions, first remove the grease drain plug and wipe all the dirt and debris off of the grease fitting and the nozzle of the grease gun. With the motor running, pump fresh grease into the bearing while observing the old grease that is being forced out of the grease drain. When the purged grease looks fresh, stop pumping. Run the motor for at least 20 minutes to purge any excess grease and then replace the drain plug.

Caution: Remember that the shaft is rotating. The motor is coupled or belted to something, so there are lots of things to get hung up in. You probably need all your fingers, so work safely.

0308_lubrication_fig21Some manuals say to “pump 0.8 ounces of grease into the bearing.” That sounds simple enough. Many operators know how many pumps it takes to deliver an ounce of grease, because they actually have checked. But, it is hard to determine if the passage between the grease fitting and the bearing is full of grease or empty. What if that precise 0.8 ounces of grease doesn’t even fill the grease passage?

Ultrasonic equipment affords a more reliable way to know when the grease reaches the bearing. While listening to the bearing, pump in fresh grease until the sound changes for the better. If you pump four tubes of grease into a 5 hp motor and still don’t see any grease coming out of the drain, please stop! Tell the boss what you did, and be prepared for him to yell a little.

If he’s fair, you’ll probably get the task of removing the motor, cleaning out all that excess grease (Fig. 2) and reinstalling the motor.

There are some good, low-tech ways that make it easier to do a good job. One way is to replace the drain plug with a low-pressure (0.5 to 1 psi) pressure relief fitting. That makes removing the drain plug or waiting for the grease to purge unnecessary.

0308_lubrication_fig31For motors installed in out-of-the-way places, bearing suppliers sell another useful device—a small grease can powered by a watch battery that provides a regulated flow of fresh grease to the bearing (see Fig. 3). Simply screw it onto the pipe in place of the grease fitting. Be sure to write the date on it and replace it annually or semi-annually.

Specialty equipment
All the specialized equipment in use today around the world makes grease selection more complicated. Specialty applications like kilns or ovens may be good places for synthetic grease. Synthetic grease typically can handle 30 C-degree higher temperatures than conventional grease, but it’s not as suitable for high-speed operation. To avoid compatibility problems, be sure to identify all special cases.

Belted applications may require an extreme-pressure (EP) grease. It might be a good idea to identify these motors in some clear way—like painting the end bracket a different color from your other motors. The color won’t match the rest of the motor, but it will make it easier to identify a roller bearing that has a shorter relubrication interval and requires an EP grease. Be sure to tell your service center whether a motor is direct-coupled or belted when sending it out for repair.

End notes
Most premature motor failures result from bearing damage that may have been prevented with good lubrication practices. Choosing the right grease for the application and following the correct lubrication schedules and procedures will assure long, trouble-free motor life with a minimum of unscheduled downtime. It’s also important to avoid mixing incompatible greases and over-greasing. Finally, when sending a motor out for repair, make sure the service center motors knows what grease you use. MT


Chuck Yung is a technical support specialist at the Electrical Apparatus Service Association (EASA), in St. Louis, MO. EASA is an international trade association of more than 2100 firms in 50 countries that sell and service electrical, electronic and mechanical apparatus. Telephone: (314) 993-2220; Web: www.easa.com

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1207

6:00 am
March 1, 2008
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Gear And Reducer Inspection And Analysis

0308_gearanalysis_11Where do you start? What’s important? How do know that you’re doing it right?

When a small reducer fails, in most plants the usual reaction is to replace it without even opening it up to see what happened. But, when a large or critical unit is involved, the inspection and evaluation can be incredibly intimidating.

Where should the inspection start? Is the foundation and grouting important? Are those pits on the teeth something to worry about—or is the gear good for another 10 years? What sort of a contact pattern is acceptable and when is it a warning of problems? Is that oil the correct viscosity? Is it contaminated?

Gear design
In gear design, there is a combination of rolling and sliding motions. At first contact between two teeth, the motion is mostly sliding but as the two pitch circles become closer and closer, more and more rolling occurs. When the pitch circles intersect, and the teeth are on the centerline between the two shafts, the contact is all rolling. Then, as the teeth go out of mesh, there is progressively more and more sliding.

Gear drives and reducer units are designed using some basic rules. The bearings are based on a certain L10 life, while the teeth have to withstand the operating fatigue stresses. These stresses are complex and provisions have to be made for cantilever loading, similar to a beam in bending; Hertzian fatigue loading of the contact surface, similar to a rolling element bearing; plus sliding friction and the lubrication demands of a pair of surfaces that involves both sliding and rolling. This sounds confusing, but evaluation and failure analysis of gear drives and reducers isn’t terribly difficult—if some simple rules are followed.

Starting the inspection
With the unit running, conduct a general inspection of the area around the gears or reducer, including support structure, bolting, foundation block, baseplate and grout. (These elements need to be in good condition so they can help resist forces that distort the housing and cause excessive gear and bearing wear.) Be sure to conduct a detailed vibration analysis and:

For an enclosed reducer…

  • Determine if there are significant differences in vibration levels in the reducer housing, the baseplate and the foundation block. There should only be a small percentage of change in vibration as you go from housing to baseplate and then on to the foundation block. A large difference indicates a looseness problem that will increase the operating stresses.
  • Listen to the unit with a stethoscope. Are there any unusual or irregular signals or noises that indicate cyclical loading, looseness, or other problems? Gear units are designed around given loads and the peaks of those cyclical variations can be a problem.

For an open gearset…

  • Use the stethoscope to listen to the pinion pillow blocks, again searching for any unusual or irregular noises. Then, listen to the bearings while watching the gears rotate, looking for cyclical noise patterns that match the pinion or bull gear rotation, which may be clues to problems.
  • Carefully open the guard so you can watch the tooth mesh with a strobe light,and:
    • From a side view, try to understand and measure the eccentricity in the bull gear.
      • Root clearance on a spur gear ideally should be 0.071 X tooth height, but there is always some runout. On large gears, the minimum allowable is generally taken as 0.05 X tooth height.
      • Interference is an invitation to disaster. Too much clearance is always better than interference, but it changes the tooth meshing geometry, increasing the cantilever tooth loads, and the wear rate.
    • From a head-on view, analyze how the contact pattern changes as the bull gear rotates.
    • Using an infrared thermometer, measure the temperature variation both across the teeth and around the gear to get an idea of the loading and misalignment. (For good reliability, the maximum variation should not exceed 10 F.)

At about the same time:

  • Look at input power data and calculate both the peak and average power required by the unit. Compare these data to the machine’s design and rating.
  • During a heavily loaded period, take housing and lubricant temperatures.
  • Take an oil sample and:
    • Calculate if viscosity at that peak operating temperature is acceptable.
    • Compare the wear particle analysis with historical data.

With this data, you’ll have a good start on the overall evaluation and an insight into any impending problems. Now, it’s time for visual inspection and evaluation of the gears.

0308_gearanalysis_fig11

Understanding unit metallurgy
The first step should be to determine the tooth hardness and understand the metallurgy. Most industrial gears used today in North America and Europe are case hardened (also called surface hardened) to somewhere between HRC 54 and HRC 63, and they should never show measurable wear or pitting. However, large gears, open gears sets and many older reducers will have through hardened teeth with hardness values anywhere from BHN 140 to about BHN 400.

Further confusing the issue is the fact that from the 1960s through the 1980s, some manufacturers supplied larger reducers with case hardened pinions and through hardened gears. Additionally, while most open gears are relatively soft, some manufacturers made their products from medium carbon steel and then flame hardened the teeth to about HRC 36.

If the tooth’s hardness is above HRC 40, treat it as though it were case hardened. If you don’t have a hardness tester, use a fine file and try to cut the top of the teeth. If the file just skids, you know that the teeth are hardened.

The next step is to understand the contact pattern during operation. The ideal is to have a contact pattern completely across each tooth that was uniform all around each gear. This design is based on full contact, but sometimes there are machining or assembly errors and other times there is distortion of the housing. Consequently, tooth stress can increase tremendously (see Fig. 1.)

0308_gear-analysis_fig21

In addition…

  • Less than full contact should be carefully documented.
  • Any evidence of contact on the back of the teeth is cause for great concern as it indicates very high peak tooth loads, and the manufacturer or a skilled consultant should evaluate the situation.

Inspecting through hardened gears
A difficult part of your analysis comes when you try to convince people that pitting of a through hardened gear is not only nothing to be overly concerned about, but that it also can be used as a predictive tool.

There have been many articles written about the various forms of through hardened gear wear and pitting. In them, you will see terms like polishing, corrective pitting, destructive pitting and normal dedendum wear. Unfortunately they all mean that the gear is wearing out. From an operational and maintenance viewpoint, what’s most important is determining the rate of wear.

Through hardened gear pitting…
Through hardened gears rarely break teeth. Because of the high local contact stresses, they usually wear and pit. The aforementioned damage classifications refer to the pitting rates. Through hardened gears usually are:

  • Designed with huge safety factors with respect to the cantilevered bending stresses.
  • Generally made from relatively tough materials.
  • Designed so corrective pitting makes up for minor surface irregularities and misalignment. This initial wear removes the areas of hardest contact and slowly redistributes the load over a greater surface area. Then, as the contact becomes better, local stress decreases and the wear rate drops rapidly (see Fig. 2).
0308_gearanalysis_fig31

Normal dedendum wear is fine pitting seen in the dedendum of teeth. It occurs after millions of load cycles when a minimal oil film and sliding contact put the tooth surface into tension. The result is minor cracking and pitting and slow removal of the dedendum surface.

Destructive pitting, like that shown in Fig. 3, happens when the lubricant is grossly overloaded and large or sharp pits develop. The result is a noisy and rough gear in serious trouble with rapidly increasing damage. If the pits are relatively small and well rounded, they can support the lubrication film and the gear will last a long time. At the other extreme, large irregular pits destroy the lubrication film and sharp, linear pits can cause formidable stress concentrations.

In through hardened gears, corrective pitting and normal dedendum wear result in slow and measurable tooth deterioration—which typically allows for a relatively long and predictable life. Destructive pitting, though, will rapidly grow rougher and noisier and may result in a catastrophic failure. Early in the gear’s life, it may be difficult to determine if the wear is corrective or destructive, but with corrective pitting the wear rate rapidly drops off.

0308_gearanalysis_fig41Rolling and peening…

The most common other damage seen on through hardened gears occurs when the teeth are so heavily loaded that plastic deformation occurs. This is commonly called rolling, where metal is rolled or pushed up the active faces of the teeth (see Fig. 4), and peening, where the shape of the tooth is hammered irregularly until it is no longer an involute curve. In both rolling and peening, the tooth form is slowly destroyed and both mechanisms show that either the gear is very heavily loaded or there is poor lubrication.

The amount of allowable wear depends on the possible consequences of a failure. If it is not a critical application, through hardened gears are frequently run until the pitch line thickness is reduced by more than one-third. On the other hand, with a critical mine hoist, the loss may be limited to only 15%.

Through hardened gear predictive monitoring…
One positive point about through hardened gear wear is that the wear can be easily monitored. Using a gear tooth micrometer as a predictive tool and periodically taking measurements at several points across the teeth and around the circumference, the charted wear rate can be used in planning for gear replacement, evaluating lubricants, etc.

Inspecting surface (case) hardened gears
Most of the confusion in evaluating gears occurs because surface (case) hardened gears, unlike through hardened gears, can tolerate almost no surface damage. On a surface hardened gear, even small pits—those that would be ignored on a through hardened unit—can be indications of a looming disaster. Thus, Best Practices demand that the evaluation of surface hardened gears has to be very different from that of through hardened components.

The case on a surface hardened gear is much harder and much stronger than the softer core. These gears are almost always machined to much closer tolerances than through hardened gears—and the hardened surfaces tend not to wear. Consequently, damage to that hard external “shell” frequently is difficult to see, making surface hardened gears and reducers far more difficult to inspect than through hardened ones. Because the hardened case is not very ductile:

  • Alignment is much more critical than on through hardened gears.
  • Once damage penetrates the hard outer case, it grows rapidly through the weaker core.

Most surface hardened gears have relatively thick cases from carburizing or carbonitriding, but some have very thin nitrided cases.

0308_gearanalysis_fig51

The internal inspection of surface hardened gears should begin with a VERY careful inspection of the teeth and the contact patterns. The teeth should look like new and show no surface damage other than mild polishing—using a bright light for the close visual inspection of the teeth is strongly recommended. Because of the fine surface finish, determining the contact pattern on surface hardened gear teeth can be difficult at times. That is why you may have to look at them from several angles.

One note of caution: Some folks run carbon paper through a gear set or use bluing to check contact patterns. We have no problem doing this, but there are many times when it is misleading because the dynamic forces on a reducer or gear set in operation cause deflection of the housing or the machine base. In these applications, the static contact check is almost useless and may lead to a false impression as to the contact pattern. There is no substitute for that previously mentioned careful visual inspection.

While broken teeth clearly are the most serious problem, because of the relative weakness of the softer core material, any tooth that has substantial surface deterioration may be at risk of breakage. The following section describes some common forms of tooth damage and the dangers they present.

0308_gearanalysis_fig61

Pitting and micropitting…
The most common surface damage mechanisms are pitting and micropitting. Gear pitting occurs as the result of a combination of Hertzian fatigue forces and surface tension. Any pits on a surface (case) hardened gear are cause for great concern because they show that the tooth loads are far in excess of the design loads. Pitting also is indicative of either serious overloading or metallurgical problems. In addition, once the strong and hard outer layer is penetrated, the remaining core is much weaker and there is a good chance of tooth breakage in the very near future.

Micropitting, a less severe form of surface fatigue damage, sometimes occurs when there is an inadequate lubricant film. It shows up where the high spots of mating gear surfaces create pressures great enough to cause a series of tiny fatigue spalls that look as though the area had been sandblasted.

If the micropitting occurs in bands—and is uniform and well distributed—it indicates that the gears are heavily loaded and there are some machining errors. This type of micropitting, however, poses no real problem. For example, in the pair of 30-yearold case hardened gears from a 900 hp reducer in Fig. 5, there is no perceptible wear except for the bands of micropitting across the teeth. Although this shows that these gears are heavily loaded, after having run for several billion cycles, the degree of micropitting they reveal is not a cause of concern. However, when micropitting is off to one side of a gear, as shown in Fig. 6, it indicates there is excessive misalignment within the unit and a serious chance of catastrophic failure.

0308_gearanalysis_fig71

The normal progression of damage in a surface hardened tooth with excessive loads and misalignment is that the micropitting eventually yields to pitting, followed rapidly by tooth fracture. By the same token, if the entire active face of the teeth was covered by micropitting, it would indicate that the teeth are extremely heavily loaded, the lubricant film isn’t adequate and there is a substantial likelihood of pitting and eventual catastrophic failure

Other common surface hardened problems…
Poor tooth contact and the eccentric loading that causes pitting and the resultant tooth fracture are the most frequently seen surface hardened gear problems. Several other tooth damage modes have to be recognized, though.

Rippling (see Fig. 7) occurs when the contact loads are so heavy that there is plastic deformation of the hardened case. Inspection of a rippled tooth surface will show surface variations that look like ripples in water and should be watched carefully.

0308_gearanalysis_fig81

Case crushing is seen when the load on the case is so heavy that the ductile supporting core plastically deforms, can’t support the case and the case fractures. The typical symptom is a crack horizontally across the tooth, indicating the loads are excessive and the tooth is in danger of breaking.

Metallurgical problems…
There are many metallurgical defects that can cause gear problems—most of which are beyond the scope of a basic article.

One such defect that is within the scope of this article, however, is the appearance of a single large spall or a few large spalls on well separated teeth (see Fig. 8) This is typically the result of manufacturing problems. If these large surface flaws are well separated, they don’t require immediate action. Nevertheless, they should be carefully monitored, with plans for eventual replacement.

Concluding thoughts Now that you understand the condition of your gears and the severity of any damage, think about the fact that there are always multiple contributors to machine deterioration and equipment failures. Go back, review the installation and, with the help of your PdM findings, you can understand those changes that will most efficiently improve your gear and reducer life. MT


After a long career in industry, Neville Sachs joined with Phil Salvaterra in 1986 to form Sachs, Salvaterra & Associates, Inc., a reliability consulting group of engineers and technicians, headquartered in Syracuse, NY. Since then, he has conducted thousands of failure analyses and hundreds of failure analysis classes across North America. A Registered Professional Engineer, Sachs is a member of and active in several engineering societies and a frequent speaker for both regional and national programs. He is the author of Practical Plant Failure Analysis: A Guide to Understanding Machinery Deterioration and Improving Equipment Reliability (CRC Press, 2006), and also has contributed significant sections to two other technical books. Contact him directly at: sachscracks@att.net

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226

6:00 am
March 1, 2008
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Uptime: Getting Operations’ Buy-In For Reliability

bob_williamson1

Bob Williamson, Contributing Editor

This is the third installment in a series on “Developing & Deploying a Reliability Culture” that began in the January 2008 issue.

Getting an organization to the point where equipment and process reliability makes sense is essential for successful capital-intensive businesses.

Noted reliability expert Paul Barringer, of Barringer & Associates, Inc. reminds me that “The key to success with reliability lies with management and (their) adoption of a failure free environment…to preserve the process (without failure) to keep the money machine operating.” In other words, top management, senior leadership, must lead the charge for developing a true reliability-focused work culture. While this is an absolutely crucial step, it is not always an easy step for this level of management to take.

Not long ago I made my usual statement to a plant leadership group that “Equipment and process reliability is AS IMPORTANT AS quality, workplace safety, and environmental compliance.” You actually could see the management team bow up at that statement. Then team members began talking how important safety really was around their facilities: “It is our TOP priority here. Without a safe workplace we would be out of business.” And they were right.

We have to ask ourselves what happened to get these top level managers to be so insistent on workplace safety. Moreover, we also need to ask WHAT MUST HAPPEN for them to see that while safety is of utmost importance to business success, so are quality, environmental and process reliability (absence of failures). This is not a case of one or the other. It is ALL OF THE ABOVE—quality and safety and environmental and process reliability. In fact there is a natural synergy among these four TOP priorities.

Getting plant operations’ leadership and plant floor work groups to buy-in to equipment and process reliability requires some new education and some paradigm shifting. In many organizations the “we’ve-always-done-it-that-way” mindset prevails UNTIL there is a new no-options set of priorities and accountabilities with consequences. That’s part of what makes safety and environmental so important to businesses—regulatory compliance is not an option. Outside governmental agencies WILL enforce their safety and environmental regulations. Plus, the financial impacts of non-compliance accidents and incidents appear directly on the financial balance sheet as an expense (a loss). From another perspective, safety and environmental compliance become “risks to be managed”—the more critical the risk the more it is managed.

Regulatory or voluntary compliance
Helping plant operations’ leadership and plant floor work groups to buy-in to equipment and process reliability requires that we also understand the earlier voluntary transformations they had to make for the sake of competitive business success. For example, ISO 9000 ushered in internationally recognized certification standards and registration for “quality management systems.” The “Big Three” U.S. automakers then followed up with their own QS 9000 standards that incorporated auto industryspecific quality systems requirements. That was followed by ISO Technical Standard 16949, an international automotive industry quality systems standard. Each of these standards included very specific requirements, criteria, audits and registration procedures that had to be met for continuing registration and as a condition for continuing supplier status.

Similarly, environmental protection has become a progressively more critical business issue over the past few decades. The U.S. government’s Environmental Protection Agency (EPA) developed and promulgated ever-increasing regulations regarding pollution abatement and prevention. EPA’s regulatory process was similar to the U.S. Department of Labor’s previously developed Occupational Safety and Health Act/Administration (OSHA) regulations. Violations of these regulatory guidelines were punishable with fines and even imprisonment for willful neglect. Then, many businesses voluntarily pursued the new ISO 14000 standards for “environmental management” similar to the earlier quality management systems standards of ISO 9000. Likewise, ISO 14000 included very specific environmental performance requirements, criteria, audits and registration procedures that had to be met for continued registration.

Today’s reality
Within ISO 9000, TS 16949 and ISO 14000, there are sub-sections that deal with criteria for “preventive maintenance programs for key process equipment” (TS 16949, clause 7.5.1.4, for example). But, these are small portions of the overall quality and environmental “process reliability” guidelines. While most businesses comply with governmental safety, health and environmental regulatory requirements, there are many businesses that do not pursue the voluntary standards for quality and environmental management. Sure, there are clauses and sections within the government regs that address some aspects of “maintenance” but, what “standards” or “regulatory requirements” exist for equipment and process reliability? Virtually NONE!

When you Google for “Quality audits,” “…certification,” “…checklists” you’ll find millions of sources, including ISO 9000 and TS 16949. Google for “Environmental audits,” “…certification,” “…checklists” and you will find hundreds of thousands hits, including ISO 14000. However, Googling for “Equipment reliability audit,” “…certification,” “…checklists” generates just seven sources, and only for “equipment reliability audits”—nothing like the nationally and internationally recognized safety, quality, or environmental standards. The sad reality? Equipment and process reliability are NOT perceived as important to business as are safety, quality and environmental issues. Yet, doing business with unreliable processes can be very expensive, time-consuming, frustrating and, at times, even disastrous.

Achieving buy-in
What really happened over the years that made quality, safety and environmental so important to companies? Do you suppose it was the public image, employee revolts, customer complaints, regulatory fines and sanctions or business reputation and recognition? Sure, all that had an awful lot to do with it. So did the high costs associated with workplace accidents, environmental incidents, customer complaints and lost market share! Businesses could measure the costs associated with each of these situations. They tracked and trended the occurrences and costs, then did something about the causes. It was almost a no-brainer.

So, what about equipment and process reliability? In the absence of obvious regulatory compliance pressures, we have to focus on the costs associated with unreliable equipment and processes.

The cost of unreliability
Almost 20 years ago, several of us in the Total Productive Maintenance (TPM) and Reliability- Centered Maintenance (RCM) consulting fields started talking about the “cost of failures” and the “cost of unreliable equipment.” We asked, “Do you know, or can you find out what an hour of downtime costs the business?”

If you dig enough, if you ask the right people in production and accounting, you might be able to answer that question. Once you have it, you also have the foundation for a paradigm-shifting business case for improving reliability—more production in less time, higher process efficiencies, better utilizations, higher return on net assets, better on-time deliveries, uninterrupted flows and lower costs. The more compelling the business case for reliable equipment and processes, the more operations leaders and plant floor work groups will understand why RELIABILITY is so important to competitive business success.

Try the following approach. Begin by asking the question “What does an hour of downtime cost the business?” Look at your critical processes first. Take recent incidents of unplanned downtime that stopped a critical process and “dollar-ize it” in terms of lost production, lost revenue, lost profits, late deliveries, expedited processing, etc. Lost time never can be made up. It’s lost forever. Sure, you can work overtime to catch up, but that’s paying double to produce the same amount—a false economy. Think about it this way: What would an hour of downtime cost a NASCAR team? Could the team quantify the impact of such downtime on the business? You bet! Could they ever make it up? No way!

Focused improvement
Focus on the critical processes, the critical few. These processes, for example, can be a chilled water system, a production line, steam system, a complex multi-station machine, a material handling system, a dust collection bag-house or a wastewater treatment system. Next, target the weakest links within those processes. Determine the root causes of the problems and eliminate them. Develop the “reliability business case” for making these critical processes problem-free, one equipment component at a time.

Synergy…
The whole is greater than the sum of the parts. That says it all. Here are the options: We can champion a Safety Program, a Quality program, an Environmental Program and/or a Maintenance & Reliability Program with the appropriate departments taking the lead to fulfill management expectations. Yet, the real sustainable breakthroughs happen when we put them all together with an equal emphasis. That’s synergy!

Workplace safety…
Ron Moore, author of the book Making Common Sense Common Practice, made the statistical observation that workplace injuries increase as equipment breakdowns increase. The opposite occurs, too. The more reliable the plant, the fewer accidents and injuries you can expect. Clearly, there is a direct correlation between accidents and equipment reliability.

Quality and yield…
Many of us also have observed that the more reliable the manufacturing processes, the higher first-pass quality yields, the less waste and rework.

Environmental…
The more reliable the environmental equipment and processes the fewer incidents.

Maintenance…
The reduction of “reactive maintenance” work because of more reliable processes makes more time available for planned, preventive, predictive and proactive maintenance work. What a powerful business model for process reliability— capital-intensive business processes doing what they are supposed to do, first time, every time!

Getting operations’ and plant floor leadership buy-in for reliability is a joint effort, a partnership whether the maintenance group takes the first step or the operations group does. Reliable processes produce revenue. Cost effective reliable processes produce wealth. MT


References

  1. Moore, Ron, Making Common Sense Common Practice: Models for Manufacturing Excellence, 2002, Butterworth- Heinemann, Woburn, MA.

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