An effective MIP (machinery improvement program) depends on communication. Certain departments have recognized the necessity of thoroughly documenting all relevant details of machinery as part of their normal routine. However, others have not only been exempted from detailed documentation in their work but have grown apprehensive, defensive, and resistant to paperwork that seems to not be of any use to them. These are usually the people who have the greatest opportunity to provide information about the machines. A fundamental shift in thinking must take place in how those individuals view their jobs (and even themselves), and how others think of those individuals.
Seminar attendees, primarily craftspeople, have often expressed certain attitudes. The following are quotes heard by the author countless times:
- “They think of me as an extension of the wrench”
- “They don’t pay me to think, that someone else’s job”
- “If they don’t ask, they don’t need to know.”
- “If you say too much, they will use it against you.”
Such attitudes effectively remove the “front line” people from most of the formal communication process.
With so many factors to consider and details to pay attention to, the optimum communication cannot take place by memory, word of mouth, and hearsay. Politics, distrust, and a lack of a basic understanding others areas of expertise compound the problem. Improving technical details is relatively easy compared with changing communication styles. While having well designed forms and procedures do not change all communication it can provide a framework for a more effective process of sharing information.
The two scenarios presented below are intended to demonstrate the potential effects of having or not having a program with the characteristics listed above. Neither of the “case histories” are actual events at real locations. The first of the two stories is compiled from many real events and attitudes from programs at various companies and locations. The author has heard of these types of actions and attitudes existing to various degrees at a majority of the plants he encounters. The second story, also built from pieces of various programs now in use, creates a somewhat Utopian picture of how things could work if the right communication tools are in place and the right attitudes are prevalent.
Some examples of suggested documentation and communication tools will then be looked at. While a few forms will not change the more difficult problem, that of attitude, putting forms procedures can be a useful place to start. Ways of enhancing the process by using appropriate technologies will also be discussed.
Note: “Poetic license” has been applied liberally but any exaggerations, particularly in the area of attitudes, is only intended to laugh at our collective hang-ups and is not intended to assign blame or criticize any particular group. The names of the participants have not been used at all to protect the innocent. Any resemblance to co-workers, bosses and even one’s self is purely coincidental.
Case #1
A process plant at a typical location (not selected for its scenic value)
A vibration analyst finds that spectra on a pump are showing some non-synchronous peaks in the lower harmonic range. He believes that they are bearing frequencies, but is not able to confirm, as there is no record indicating what bearings are in the machine. He tells the assistant maintenance manager that the bearing will have to be replaced “in the near future.” When asked “how long can they run the machine without replacing it?”, the analyst remembers a recent incident where he said the same thing about another bearing that appeared to have more damage and the response was to try to run until the next shutdown. The bearing failed before that time and some comments were overheard about the ineffectiveness of the vibration program. Rather than indicating that this bearing in the pump is at an earlier stage, he simply refuses to answer, saying that he will document his suggested course of action in his report.
The infrared thermography technician, who happens to be passing by and recognizes which machine they are discussing, notes that the pump in question runs hotter than the other four in that row, probably because it is in a corner of the room where there is little air circulation. The vibration analyst remembers, as this technician interrupts their conversation, that some of the comments he overheard after the previous incident were, in effect, implying that infrared thermography might be a more reliable technology for condition monitoring than vibration.
All three speculate that the real fault could be misalignment due to uncompensated thermal growth differences. The vibration analyst goes back to his computer and looks again at the spectra on the pump. He finds a slightly high 1 x rpm and a higher than usual 2 x rpm, about even with the 1 x rpm. As this seems to confirm the misalignment theory, he then goes to the maintenance supervisor to find out how this was aligned last time.
The supervisor reluctantly calls his top mechanic to find out more about the situation. He’s reluctant because he had been put on the hot seat many times when the vibration program was first starting and he was a mechanic. The mechanics under him are tired of feeling accused by him of screwing up, all based on the word of some vibration analyst (who incidentally is some engineer who has never turned wrenches for a living in his life). The supervisor had been determined to use his anticipated greater influence when he got the promotion to not let the mechanics take the heat for everything. On the other hand, he knew he did not want to get into it with the analyst and argue the technical stuff because he didn’t have any vibration knowledge and he hated being talked down to.
The supervisor doesn’t know for sure who did the last alignment on that particular machine but this mechanic is the one who does most of the alignments on critical machines (and the least likely to show any ignorance about alignment procedures). The mechanic does not remember doing that specific machine and doesn’t think that it has been worked on for a long time. In fact, he thinks it had run trouble free for a long time. He remembers that he had aligned several of the other pumps in that row over the last few years. When asked if he had compensated for thermal growth he said of course. All the mechanics went through an alignment course a few years ago and have focussed on precision alignment since that time. The course covered thermal growth extensively.
The analyst asks if the thermal growth was calculated or if the manufacturer’s estimates used. The mechanic, mildly impressed that the analyst knew enough to ask the question, yet still annoyed that he is still looking to the blame a mechanic in some way, says he remembers calculating thermal growth based on actual running and non-running temperatures on more than one of those pumps. However, he also remembers that they were very close to the manufacturer’s recommendations. When other alignments were done on those pumps when time was limited, the machines were offset for thermal growth to the manufacturer’s recommendations.
The supervisor says that before the training, there were only a handful of mechanics who did alignments on hot machines. One particular mechanic came to mind, but he was no longer with the company. He recollected that this mechanic was very thorough and he kept notes on such things as thermal growth. Unfortunately, none of those notes meant anything to anybody else at the time of his departure and therefore nothing was passed on. The supervisor did not like the possibility that this could be blamed on this diligent mechanic who was no longer there to defend himself.
The vibration analyst says that besides the spectral data (which he knows they don’t want to hear about anyway), the reason they suspect misalignment due to thermal growth is because the infrared showed that that pump ran hotter than the others did because of its location. If the person who did the alignment didn’t have the time to calculate thermal growth for that particular machine, then his only course of action would be to align to the manufacturer’s specs.
The mechanic points out that in a typical situation the machines are cold when they are sent out to do an alignment and there is no opportunity to do anything but use the manufacturer’s numbers anyway. The supervisor and mechanic see the logic and now feel that the cause is not being blamed on a lack of diligence on the mechanic’s part. The mechanic says that it’s a good thing that the infrared team is around to save the day. The vibration analyst grinds his teeth.
Wanting to get credit for finding the problem first (for the good of their programs), both the vibration department and the infrared team submit reports to the maintenance manager. Not understanding the actual data but noting that two reports have come in on the same machine on the same day, the maintenance manager calls the assistant maintenance manager to ask about the problem on the pump. He replies that he is aware of the problem and has spoken to both the vibration analyst and the infrared technician about it that very day and that they think it is misaligned due to thermal growth. The manager adds that both reports say the same thing and that the vibration report also adds that the supervisor and the mechanic who would know about the situation also agree.
The assistant manager points out that there seems to be a lot of concern about this situation as so much activity has gone on that day. The manager remembers the heat that he took after he tried to make it to the next shut down after the vibration analyst had warned him of a bad bearing. He remembers getting grilled about the cost of the unscheduled down time and the “I told you so!” response from the analyst. He never told the analyst the total cost of the failure because he already had enough people upset with him. He then writes a work order for changing the bearing on the pump and realignment, ending with the most worn-out letters of his keyboard – ASAP.
The mechanic who was involved in the previous conversation is assigned to change the bearing and align the motor and pump. Knowing that the issue was thermal growth, he first took temperatures on both machines. After recording the temperatures, he began the shut down and lockout procedures, but not before the production manager asked the operator why the mechanic had not started yet. The operator replied that the mechanic said he was “going out to do some sort of preliminary checks before he started the alignment.” The production manager sends the operator to remind the mechanic that this is an unscheduled shutdown, and nobody gets paid if the machines don’t run. The mechanic grinds his teeth.
After being reminded that this was not a regularly scheduled shutdown the mechanic is very aware that there is a great deal of time pressure. While detaching the coupling to check for lubrication, he noticed that one of the coupling bolts had a washer missing and another on the other side seemed to be longer than the other bolts. He speculated that this was done on purpose to compensate for an unbalance in the coupling or other part. As he was in a rush, he didn’t feel he had time to pursue the issue and reminded himself that they didn’t see signs of imbalance but rather saw signs of misalignment. To avoid making anything worse, he match-marked the coupling halves and labeled each bolt and washer, returning each to its original position when reassembling.
Upon removing the bearing, the mechanic sets it aside for future analysis. The bearing given to him had a number on the box of NTN 6308 ZZ P6/9B. Looking at the old bearing, though dirty and worn, he can read that this was also a 308 bearing. Therefore, everything seemed to check out.
The mechanic knows he is under the spotlight. To make sure everything is all right, he checks the tolerance on the shaft and the housing. Both are within tolerance. The bearing is installed properly.
The alignment is done using a new laser system. Since the laser has a resolution of one micron and accuracy of .02%, the mechanic anticipates he will be within tolerance in a couple of moves. When that doesn’t happen, he resorts to an “extreme” measure – he removes the soft foot. His final readings are within the “excellent” tolerance column with the thermal growth offsets. As the final moves are made, he sees the operations manager about 60 feet away looking at him while pacing back and forth. The mechanic slows down just slightly when he sees this.
The mechanic inquires as to what grease is usually used in the pump. The lube man replies that the best grease for that pump, in his opinion, is already in the grease gun by the door and that six pumps should do it. The mechanic puts in the six pumps called for and just to be sure, gives it one extra pump.
When the machine starts up again, the analyst and the mechanic are present, and it is running rough. After the maintenance supervisor comes by and the machine sounds a little better, they decide to take readings. The analyst says the misalignment looks bad as the 2 x rpm is even higher than before. The mechanic is about to blow his stack when the operator (of all people) walks up and says that this machine usually takes about 45 minutes to get to its smoothest operating condition. The mechanic gives him a nod of approval (with a look of surprise).
One hour later, when all return to take readings, the 2 x rpm is lower and now is about equal to half the 1 x rpm. No bearing frequencies are present. The analyst, while somewhat pleased, mentions that while better than before, there still seems to be a bit of misalignment. While the mechanic prepares to let loose and the analyst stiffens, the operator, encouraged by the response to his last observation, walks up and says that it doesn’t seem to be running any smoother than before, and that he can tell the difference even without one of those fancy boxes. The mechanic looks at the analyst who rolls his eyes. A tension-releasing laughter breaks out among the maintenance people. Walking away, the operator grinds his teeth.
The maintenance manager hears that the pump bearing has been replaced, the vibration is not in alarm, and that everyone is satisfied that the problem is solved. The best part is that it was a team effort, using input from vibration, thermography, mechanics, lubrication and, yes, even operators. The cost of the repair was estimated at $700, plus five hours lost production, which compares quite favorably with the last incident where the bearing failed, costing just over $13,000 in repairs and three days lost production, partially due to lack of parts on hand. By making the call to replace the bearing at that time, the result appears to be $12,300 in savings, which should show the plant manager how much more effective the maintenance manager and his people are getting.
Six months later, the gossip is that the same bearing is now starting to go bad, and only the operator can say “I told you so!”
The Rest of the Story:
The thermal growth was calculated from actual temperatures by the mechanic (no longer with the company). Before leaving, he did pass on to the maintenance manager all of his notes regarding the machines that he worked on. There the notes sat for a few days. Not knowing what to do with them, he eventually threw them away. The 1 x rpm vibration was due to the unbalance in the coupling. The 2 x rpm was amplified by a resonance in the base. The bearing that was removed was on the high end of the bore tolerance (though never checked), and the shaft was oversized by 0.0002 inches. The RIC on the removed bearing was a C3; however, the new bearing supplied to the mechanic is a CÆ. Also, the new bearing is on the tight side of the bore tolerance. The bearing had grease in it, with shields on both sides that are removed for this application. The grease that works best for the application is not compatible with the grease already in the bearing. The amount of six pumps with the grease gun is based on starting with an empty bearing, not a full one.
With the reduced clearance, the same amount of thermal growth, the tighter fit, the over lubrication, the mixing of incompatible greases in the bearing and the continued presence of the unbalance and resonance, the new bearing failed in an ever-shorter time than the previous one. Only the subjective observation of the operator gave anybody an indication that something was wrong.
Building a Documentation and Communication Process
What went wrong? In addition to not having enough recorded information to draw from, there were other factors that contributed to the situation. To begin with there was an exaggerated sense of urgency expressed by the analyst because of distrust in the assistant maintenance manager’s ability to make informed decisions, which was well earned. This was followed by lack of thorough investigation that examines all possibilities and determines the root cause of the problem. This was due in part to the politics that pushed him to jump to conclusions. The mechanic and his supervisor were trying to protect themselves from criticism more than trying to find out what was happening with the machines. Rather than asking questions, everyone assumed when facts were not known. And finally, there was no thorough verification done to prove or disprove that the problem was eliminated after repair was completed.
The forms in the appendix are only examples or suggested starting points for creating the optimum tools for your company or plant. If they work in their present form there may be no need to alter them before putting them to use. It is recommended, however, that a careful review and customizing process take place not only to make the forms and procedures more appropriate for your situation, but also to assure that there is complete buy-in from key people by having them a part of the review process.
Case #2 Same plant, same machine conditions, different universe (due to different attitudes and record keeping)
If the plant had effective communication, documentation and a sense of teamwork between everyone in the maintenance program, then the following might have taken place:
When readings on a pump being monitored go into the first alarm level, a vibration analyst examines the spectra. When possible bearing frequencies are detected, the database shows which bearing is in that end of the pump and what the defect frequencies are. A more positive identification of ball pass outer race is made.
Since the assistant maintenance manager had a short course on vibration and has since talked with the analyst about such things, the analyst is able to explain that the bearing would be at an early Stage 3 of failure, but it is not very severe. He would suggest that they shorten the intervals between readings to keep an eye on this one. In the meantime, further analysis can be done to find the root cause of the failure.
The analyst, by checking the trend, finds that this machine has not changed much except for the slow increase of the bearing frequencies and an increase of the 1 x rpm a year ago. The 1 x rpm is slightly high in both the vertical and horizontal planes and the 2 x rpm is about even with the 1 x rpm in the vertical direction, but small in the horizontal. The axial readings are all low.
As this is one of five in a row, he looks at the latest spectra of the other four machines. All have fairly small 1 x rpm vibration and peaks at 2 x rpm (vertical only) of about 1/3 to 2/3 of the 1 x rpm. A note on one machine says that they found a foot-related resonance.
The analyst wonders if the 2 x rpm is from misalignment and accesses the records on alignment. He sees that the alignment was last done several years ago and was offset for thermal growth and was well within tolerance. Being unfamiliar with the method used, he calls the mechanic’s supervisor who tells him that while most machines are now aligned with laser systems, this machine was last aligned using reverse indicator. The man who did it, he remembers, was very knowledgeable but is no longer with the company.
Looking at the prealignment checklist for this job, it is seen that the mechanic calculated the thermal growth himself from the running and non-running temperatures. They also look at the last alignments on the other four machines. All are within tolerance; one on the high side of the tolerance is the one with the highest 2 x rpm. Surprisingly, the final misalignment is still only 3 mils off at the coupling. The analyst asks why the thermal growth offsets are a lot different for these machines than the machine that they were investigating. The supervisor said he didn’t know but wants to find out if there is any misconception or misinformation to clear up and asks to be kept posted. He also suggests that there might be a reason for the different offsets, such as that machine normally running hotter.
The analyst emails the infrared team asking if that machine is in a hotter area and if any changes have occurred recently. He then asks the operator in that area about that machine. He says the process hasn’t changed and that he noticed the machine starts rougher than the other four, but all of them smooth out after about 45 minutes. There haven’t been a lot of problems with those machines. All are needed in the high production time and he hopes they don’t have to take it down; however, if it needs work, it’s better than letting it fail.
An infrared team member calls the analyst and says that the pump in question runs hotter than the other four in that row because it is located in a corner where the airflow is very restricted. That machine has always run hotter, particularly on the side near the wall. He went out to check it that day and everything was about the same except for the inboard bearing was running about five degrees hotter than the last reading; but the last reading was just before lubrication.
The analyst talks to a mechanic to see if he has anything to add. He feels it is not an alignment problem on any of the five machines. He said he never liked those bases, however, and that they always give him fits when removing the soft foot. He also asks what the “phasor stuff” shows. The analyst admits he has not run a phase analysis because the 1 x rpm was not that high, but it would be a good idea as he trusts his mechanic’s instincts.
Phase analysis shows a strong imbalance pattern, yet there is that 2 x rpm higher than usual. He tries phase on one of the other machines and finds the same general pattern, though less conclusive (some points didn’t have enough vibration to trigger a phase reading). The mechanic, who has been helping him, says he knows of another unit just like this one that runs very smooth. They go to that machine and take a reading which confirms very low vibration with no 2 x rpm. The analyst notes the difference in the base construction. The mechanic says that this installation was much older, before they got the assistance of an engineering consulting firm that redesigned the bases on the other machines. He doesn’t think they use those guys anymore.
Since the mechanic was there to turn the wrench, the analyst tries a running-soft-foot test. As he loosens one bolt on the inboard feet, the amplitude at 2 x rpm more than doubles. The same happens on the other inboard foot. The outboard feet don’t seem to effect the readings significantly. The mechanic tries to add a shim under the second foot while it’s loose, but he can only get a two mil shim in, though not all the way, and tightening the foot returns the vibration to the previous level – no better, no worse. They agree there is a resonance in the base, which can be affected by the tightness of the hold-down bolt. Readings are taken at ten points across the base at the inboard end. A plot shows it is partially resonant to its second natural frequency.
To track down the source, the analyst then takes phase readings. All show a pattern that point to imbalance. Since the 1 x rpm appears to be imbalance and the 2 x rpm is affected by resonance, he is now starting to rule out the misalignment theory.
The balance record is pulled which shows that the motor and pump not only were balanced to the API tolerance, but were well under that tolerance. Rechecking the alignment record, he discovers notes in the prealignment checklist that referred to a lack of time to complete many tasks. Blanks show up under items such as runouts and coupling bolts.
The coupling is examined with a strobe light. One half of the coupling has a key that is too long. The other half has a bolt that appears to be longer than the rest and another bolt, about 120 degrees from the longer one, is missing a washer.
A work order is written to fix the problems the next time than particular machine goes down.
A year later the bearing reaches Stage 4 of failure around the time of a major shutdown. The work order is written to replace that bearing in the pump. When the mechanic receives it, he has several other pages stapled to it: A vibration report (where his help is mentioned, he notes fondly), and a bearing info sheet. Removing the bearing carefully, he marks the top, bottom, inboard, outboard, etc., then sets it aside after wrapping it in a clean shop towel. They may want to inspect this later. He checks the housing and shaft seat. The tolerance listed on the bearing data sheet is 1.5753” to 1.5749” for the shaft, but the shaft measures 1.5756”, 0.0006” oversized. He mics the bearing bore and finds it to be 1.5745, within tolerance but on the tight side. He mics the bore of the bearing he removed from the machine and notes that the bore was on the loose side of the tolerance. He then checks the RIC (radial internal clearance). The bearing given to him has an R.I.C. of CÆ, or normal clearance. The info sheet said that the bearing previously installed was a C3, greater than normal, which is what that machine calls for. The mechanic brings the bearing to the warehouse to ask for an explanation and a replacement.
The mechanic gets another bearing with a C3 R.I.C., (with a bore near the middle of the tolerance) and an apology from the new man in the warehouse. The man says he had never gotten feedback from anyone in his old job, but he left when he heard death threats toward him from mechanics that blamed him for many of their problems. The mechanic assures him that he’ll be fine as soon as he learns the computer system better and that most of the mechanics would be very willing to help him if he has questions about what they need.
Stopping at the supervisor’s office on the way back, he mentions the oversized shaft. The supervisor says, “Since it is already out, let’s get it done right.” A machinist touches up the shaft seat to close to the center of the tolerance, which he is very proud of. As he gives the shaft back, he mentions that he was not the one who made that shaft, according to the records.
Checking the bearing data sheet further, the mechanic sees that the shields are to be removed and the grease in the bearing is Mobil 28 MIL-G-81322. He calls the lubrication department and asks for the best grease to put in the bearing. The recommended grease he is told is not compatible with the grease in the bearing and therefore should be washed out first and then 6 pumps should be added with a grease gun labeled “# 2” in black marker. The mechanic records these details on the bearing data sheet.
After installing the bearing, the mechanic and the analyst meet at the machine a few hours after startup. All the vibration is low. The 2x rpm is higher than 1x rpm. Loosening an outboard hold-down bolt drops the 2x rpm to about half.
The maintenance manager reads the report from the vibration analyst. He decides since the amplitudes are low, any alteration of the base (or bases) could wait until next year’s budget is approved. He makes copies of the report with a note commending the efforts of each participant and sends a copy to the vibration analyst, his team leader, the mechanic, his supervisor, the infrared team leader, the operator, and the machinist. Plus, one copy to be put on the bulletin board outside the lunchroom.
NOTE: Any reference to raises given for superior work, victory parties, or all the participants getting together for a group hug are only exaggerations.
What do you want from a communication system?
- Make all relevant data available to those who may need it
- Doesn’t bog down the process with too much paperwork or computer work
- Is easily understood and user friendly
- Fosters a spirit of trust by not withholding information
- Give credit where credit is due
Who do you provide information to?
- Anyone who needs it to do a thorough job
- Anyone who could use it to contribute to the analysis process
- Anyone who could add to it or correct it
What information should be included?
- Machine details
- Trends from all monitoring technologies
- History of repairs, failures and modifications
- Tolerances, specifications and offsets
- Observations, analysis and conclusions drawn
What is the style of presentation?
- Available and accessible
- In an appropriate form for the level of training
- Attached to work orders?
- Collected as part of the routine and considered an essential part of the job
What are the potential problems?
- Nobody takes initiative
- People don’t see the importance
- People are not comfortable with using the system, (a lack of training)
- Difficult and/or time consuming to use
- “If other people don’t use it, why should I?”
What is needed to make it happen?
- The Role of the Facilitator
- Buy-in from all involved
- Training
- Accountability
- Periodic reviews and follow-up training