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A lot of facilities assign condition monitoring intervals based upon arbitrary schedules such as 30,  90, 180 or 365 days. Often, this is due to a lack of understanding of how equipment fails, misunderstanding of how conditional tasks such as vibration analysis work, available labor, and lack of importance placed upon condition monitoring efforts. These arbitrary collection intervals can actually lead to failures that go undetected and a loss of value from the effort.

To appropriately determine monitoring intervals, a couple of things should be known. First, the point in time (P) that the potential failure becomes detectable must be known (detected with vibration monitoring, for instance.) Second, the time (F) at which the potential failure would degrade to a functional failure must be known. This difference in time (P-F Interval) is the window to take corrective action and avoid the negative consequences of the failure. This difference in time will determine how often conditional tasks such as vibration monitoring must be done to detect potential failures from such things as bearing issues, etc. Typically, the monitoring interval would be set to half of the P-F interval. This allows enough time for the technology to detect the problem and for corrective action to be taken. However, in certain circumstances, it may be necessary to collect data at shorter intervals than half of the P-F interval.
It is important not to assign monitoring intervals based upon gut feelings, arbitrary calendar intervals, and so forth. Let the equipment tell you how often monitoring must be completed. Not understanding the process above can lead to costly results!

Machine components are susceptible to premature wear and corrosion due in part to the harsh environments they are placed in. To combat this, here are a few suggestions to keep your machines running:

1. Proper lubrication
   Always make sure the movable components in the machine are getting the lubrication they need. Lubrication not only keeps parts cooler and moving freely but also prevents corrosion.
2. Cleanliness
   Keep the machine components as well as their environments as clean as practical. This can aid in preventing wear stemming from particle ingression and friction.
3. Keep logs
   Keep a log of all the PM (preventative maintenance) done on your machines so as to avoid duplication and prolong the life of its components.

If you follow these simple guidelines, it will help prevent breakdowns in your plant and save money.

Grease,  excess paint,  etc. can affect the quality of collected vibration data. The below 3 steps will ensure that the best possible data quality is always collected:

1. Always carry a rag, scraper, brush, etc. to clean each measurement location before acquiring vibration data.
2. Make sure that the measurement surface is flat and the sensor is not rocking during data collection.
3. Hold the cable during data acquisition to prevent movement that may induce electrical noise and affect measurement quality.

Learn about the Triboelectric effect on vibration accelerometers

Today’s manufacturing facilities increasingly depend on Computer-Aided Machines (CAM) and robotics in their many processes. This highly technologically advanced machinery is designed with many failsafes and protection systems capable of shutting down the machine to maintain the integrity of the part being machined and the equipment itself.

As these machines typically run at very high speeds,  it is of great importance to perform condition monitoring on their bearings, motors, and gearboxes. Large amounts of debris and fluids can accumulate inside these machines during normal operation. This can complicate the use of a regular sensor and cable assembly to collect vibration data.

Consider using a small sensor with an integral cable and an armored jacket along with a vibration analyzer like the VIBXPERT® or an online condition monitoring system such as VIBNODE®. This combination of technology, sensor(s), and cable will allow your facility to reliably monitor the health of your CAM machines and maintain both performance and reliability.

Sensor with integrated cable

If non-repeatability is an issue and it is not due to the setup of the laser or ambient vibration,  then it may be of interest to check the bearing clearances. This can be accomplished very easily with a laser. A little bit of information is necessary to accomplish this. We will need the following:

a) Acceptable bearing clearance and tolerances.

b) Distance between bearings.

c) Distance from the receiver of the laser system to the first bearing.

d) Rotalign® Ultra laser system.

For instance, suppose that the distance between bearings is 10 inches, the distance from the receiver to the first bearing is 5 inches, and the acceptable clearance is 4 mils. This means that with the shaft bottomed out in the bearing, there is a total of 4 mils of clearance available, or lift. With the receiver at the 12:00 o’clock position in XY-View, press the SET ZERO button. This will give you a zero reference for the values displayed on the sensor. Simply lift the shaft until it contacts the top of the bearing and record the Y value of the movement. With the above distances, we are allowed 4 mils/10 inches, (or 0.4 mils/1 inch), 10 inches being the distance between the bearings. From the receiver to the front bearing is 5 inches, so with a good bearing, we would expect to see another 2 mils/5 inches, (or 0.4 mils/ 1 inch). Add the two together and we get a total of 6 mils/15 inches. This means that if the lift of the shaft shows 6 mils of change at the receiver, the clearance is acceptable. If greater than 6 mils, clearances may be excessive.

Tips for visually identifying loose components on a machine:

• Make sure that the machine has reached normal operating temperature,  because loose components may not appear until this temperature has been reached.
• Squirt water or soapy water on components. This may create small bubbles and allow identification of the loose component.
• Use a strobe light
• Utilize technologies such as vibration analysis and phase analysis.

Recently I visited a customer’s facility to provide onsite training for the VibXpert® vibration data analyzer they had recently purchased. Before we could get started collecting data,  we needed to build the equipment hierarchy and measurement templates required. Once the database was created, we loaded routes into the VibXpert and proceeded to collect vibration data.

The first room we entered had two large belt-driven overhung fans. At first glance, it was obvious that one of the fans was running extremely rough. We collected vibration data on both fans and paused to review the results. We noticed that the 1× amplitude on the rough fan was over 1.0 inches per second peek. The local CM technician immediately commented that the fan should be balanced and his observation was correct when simply looking at the vibration data.

The room was full of clues that explained the cause of the fan unbalance. This facility processed and manufactured wood products. Large amounts of wood dust are produced and these fans were designed to ventilate a high dust area. Everything in the room was covered with wood particles and dust. The only question was how much had accumulated on the inside of these fans.

I asked if the fan could be stopped for a short period and the inspection door opened. My request was honored and the fan was shut down and locked out. Our examination revealed the fan blades had amassed substantial amounts of wood particles. The fan blades were cleaned and resulting in a pile of wood chips weighing about 5 lbs. The fan was placed back into operation and allowed to run for several minutes. Vibration data was recollected on the fan and the 1× amplitude had reduced to 0.1 inches per second.

Fans require corrective action to eliminate unbalance conditions from time to time. However, the cause of unbalance may simply be a buildup of foreign matter on the blades. This fan was being allowed to beat itself to death due to product buildup. This facility learned a few lessons from the experience. First, inspections utilizing the human senses (touch, hearing, etc) could have been used to determine that this fan was in need of attention.

Second, periodic vibration monitoring would have identified a need for maintenance on this fan. Third, if a fan is properly balanced, simply cleaning foreign matter buildup may reduce the vibration, prevent equipment damage and maintain the reliability of the equipment. Make sure that you utilize these three steps during your daily maintenance efforts on equipment.

Advanced vibration analyzers like the VibXpert® have powerful analytical features that often go underutilized. One such feature is the ability to acquire continuous (live) vibration measurements. This can be utilized to check for measurement signal stability and quality. However,  it can also be used for additional analytical troubleshooting as well. Continuous (live) vibration data can be used to determine if electrical energy (faults, etc.) is present in electrical motors. Set your vibration analyzer to continuous monitoring. Identify and watch the peaks in question.

Turn the motor off while watching the peak(s) in the measured data. Peak(s) that disappear immediately when motor power is turned off are related to electrical energy. The remaining vibration data is associated with rotating components within the equipment.

Continuous data collection can be activated in the VibXpert analyzer by selecting the Multi-Mode icon and then the Data Collection icon that will be used. Press the Menu key, select the display setup option and toggle continuous measurement to “Yes” (it is set to “No” by default). Alternatively, you can activate the live mode by keeping the “Enter” key pressed when the measurement starts. The actual data collection begins when you release the “Enter” key.

Guest post by Brad Loucks, Mechanical Engineer at Pioneer Engineering

In a condition monitoring vibration program, determining the appropriate intervals of data collection is just as important as the data that is being analyzed. Properly scheduled data collection intervals of equipment provide data analysts with a better picture of how equipment is performing over a period of time. Having a history of data is important for an effective condition monitoring vibration program and this is done by establishing correct data collection intervals.

Data collection intervals should be established and executed with purpose, not done randomly. To establish intervals, it is important to know and understand how the equipment works. Determining the appropriate time interval between collections is done by identifying how often the equipment runs, how fast it runs, and the application. The calculations are based on the estimated life cycle of the bearings but also the estimated amount of time it takes to go from a defect to a complete failure.

Collection intervals should be a routine function. Many times data collection falls behind because the collection person is too busy to collect the data. One of the most common issues that I have come across is that plants will begin to collect data and then the person collecting the data gets pulled to do other work and the data collection gets missed and becomes more random. This is a slippery slope in that it almost always leads to the data no longer being collected. Then when an emergency comes up such as a bad-sounding machine, the analysis has not been collecting history on the equipment but they have also been out of the analysis for so long that they have a difficult time remembering how to analyze. The history and interval are just as important for proper analysis as it helps to give the analyst a more accurate analysis by allowing them to see the progression timeline.

Bearings often do not fail in a predictable time span. If this were the case, vibration analysis could be overlooked and time-based maintenance could be used. A bearing can go from a known defect to catastrophic failure over the course of a few years or it can happen within minutes. The collection intervals are calculated so that not only can data be collected and the severe defects be identified, but also to identify when a defect has formed and allowed for a history to be built in order to watch the progression of the defect. This can aid in determining whether immediate action should be taken or if the defect is at an early enough stage where proper planning and measures can be taken to avoid an immediate shutdown and loss of production.

If the equipment is deemed valuable enough or if unplanned downtime is just out of the question, then calculated collection intervals are a necessity of a proper condition monitoring vibration program. Through proper maintenance, a condition monitoring vibration program can save a plant both time and money in reducing or eliminating unplanned downtime, as well as significantly reduce the possibility of injury or death of plant staff due to catastrophic equipment failure.

Engineering advancements have resulted in many different types and grades of lubricants being available for equipment maintenance. Unfortunately,  the risk of improper selection and mixing of lubricants has increased as well. Mixing different types of lubricants (grease and oil,  etc.) within a machine is one of the most common equipment reliability problems. Doing so can result in unanticipated chemical reactions and equipment failures.

Proper labeling is a method to help ensure that the correct type of grease or lubricant is being injected into your equipment. Color-coded labels with proper lubricant identification markings should be placed on the Zerk fitting or near any lubrication entry point on a machine. Grease guns and lubricant containers should have the same color identification and markings as well. This simple process can assist in eliminating lubricant contamination and thereby prevent one of the most common reliability problems today.

Guest post by Ray DeHerrera,  Mechanical Engineer at Pioneer Engineering

Vibration analysts use multiple tools to predict a potential fault in a machine; from transducers to accelerometers,  the toolbox for vibration analysts is continually expanding to allow for more comprehensive and accurate data collection and interpretation. One tool that is absolutely important to the data analysis process is knowing how your equipment processes data. Vibration analysts need to know how results are being derived from multiple calculations within your equipment. This allows for the development of an efficient collection history that will produce more accurate results.

The calculations attempt to translate data banks into a model that can then explain the events occurring inside of your equipment. Often times the computer-processed model may develop imaginary information, thus leading to more questions than answers. With basic background and knowledge of variables that may affect your post-processed data, your questions will start to be answered.

To introduce the initial creation of our mathematical model that is displayed upon our data collector or computer screen, (such as the time waveform or spectrum) we will explore commonly used hardware such as the transducer. In general, the function of the transducer is to convert one form of energy into another. A commonly used transducer for case-mounted readings is an accelerometer. The accelerometer mimics mechanical vibrations to produce a usable signal. The usable signal is so small that typically an internal amplifier will be needed for your data collector to harness the information. This process is the initial creation of our mathematical model of data, which has been created from a response of a mechanical device (transducer) sitting upon a machine and is now being converted to a digital signal that has been amplified.

Now our signal must be stored for further analysis. There are a number of vibration collector types and manufacturers. The collector is very similar to a computer giving it the ability to quickly process the original signal into various mathematical models. One must take the time to do their research before purchasing a collector and the associated software. Many desired post-processing and collection capabilities may be limited such as sampling rates. With a good collector and setup, your mathematical models will be accurate. The accuracy and consistency in your collections are key when managing your periodic collections.

The basic knowledge of how your equipment generates your post-processed model will make your time more efficient and your results accurate. The analyst will be able to identify data that is imaginary and pick out what is real. Take the time to understand your hardware and how your computer generates each model.

Have you ever collected data and uploaded the data back into OMNITREND® only to realize that you have duplicate data in your database? As a technician,  you are pressed for time and your boss needs that report like yesterday. Every so often, when uploading the data you can get distracted by other people or from trying to juggle too many things at once, and you inadvertently upload the data twice.

You can delete the duplicated data without having to delete each one by one! Here’s how:
• Click Tools
• Select Report
• Select OMNITREND Web
• Click OK
• Click Database
• Select Database Utilities
• Select Data cleanup
• Once the data cleanup is complete click Close
• In OMNITREND click Database
• Select Database Utilities
• Select Compact & Repair

Once the Compact & Repair process is complete you can go into Machinery Manager, drill down into your database, select the task and then click the Edit Meas. Data tab on the right-hand side of the screen, and you will notice the duplicate data has been deleted.

Guest post by Brad Loucks,  Mechanical Engineer at Pioneer Engineering

When discussing machine lubrication techniques and associated maintenance tasks with industry personnel, I often hear the same story; “Once a month, we fill it up until it’s full.”  This story can unfold further to reveal that every piece of machinery under such a program receives the same type of lubricant with no considerations made to temperature change, operating conditions, load requirements, and duty cycle.  Technology has come a long way over the past several decades in every corner of the modern world and machine lubrication and oil analysis is no exception to this evolution.  It has been discovered that choosing the right lubricant for the application significantly prolongs machine life and maintains the overall health of rotating equipment in use today.

To further illustrate this point, just consider how much thought is given to the type of oil used in your car.  You won’t find a can of automobile oil in the store that is simply labeled, “Oil”.  Instead, you will find several types of oil that are specifically designed to resist large viscosity changes with changing temperature.  The ability to resist significant viscosity change is depicted using the nomenclature, “10W-30”, or “5W-40”, etc.  A common misconception is that the “W” stands for weight.  Instead, the “W” stands for “winter”, and the number that precedes it represents the oil’s ability to resist thickening when the temperature is 0° Fahrenheit.  Similarly, the second number represents the oil’s ability to resist thinning in an environment where the temperature is 100° Fahrenheit.

As you can see, the operating environment and temperature play a big role in choosing the right lubrication to extend the life of an automobile engine.  In an industrial setting, machine lubrication plays an even larger role with proportional consequences and benefits to the amount of thought and detail given to choosing the right lubrication.

Recent advancements in technology now provide us with additional tools to collect and analyze oil samples in rotating machinery.  In doing so, maintenance technicians are able to better understand the present health of their equipment as well as make determinations for further maintenance tasks to be performed.  The difference between this story and the “Once a month, we fill it up until it’s full” story, is that we now have the ability to schedule maintenance tasks based on condition, instead of relying solely on a time trigger.  A proper machine lubrication program enables us to recognize the root causes of machinery failure due to improper lubrication.  A successful lubrication program also incorporates methods for identifying lubricant contamination and implements the best practices in lubricant storage, handling, and dispensing.  By introducing these condition-based methods of scheduling maintenance tasks, machinery health is better managed, saving time and money.

Ingression can be defined as going in or entering,  a right or permission to enter, or a means or place of entering. It is important to understand, recognize, detect and reduce the effects of particle ingression. Doing so will have a very positive effect on your maintenance and reliability efforts.

Dirt is often the root cause leading to bearing damage and reduced equipment reliability. If not monitored correctly, ingression can lead to unexpected failures resulting in high maintenance and inventory costs.
When measured in the Moh’s Hardness scale, dirt is typically more abrasive than the bearing material. This leads to pitting and other damage to the bearing that reduces the life of the equipment. It’s really quite simple: under great load, something has to give and it’s usually the bearings, gears, pump impellers, etc. Our goal should be to remove contaminants from the lubricant to our target cleanliness before placing it in our equipment. Doing so will increase our equipment reliability.

If you have a vertical flange-mounted motor and need to shim it to correct angularity,  our laser systems provide the following handy options to accomplish this:

How to decide which option to use?

MINUS: If you have plenty of shims already there, you can select this option to minimize the number of shims used, since the correction will be accomplished by removing (subtracting) shims.

PLUS: if you have no shims between the motor flange and support flange, to begin with, you can select this option to affect the correction by only adding shims.

PLUS-MINUS: With this option, exactly half of your corrections will be positive (adding shims) and half will be negative (removing shims). This option is very handy if your pump impeller hangs from the thrust bearing in the motor and you do not want to change the pump shaft’s axial position. The plus-minus option makes your pivot point the shaft centerline itself so that the correction will have no z-axis effect on the shaft from shimming at all. This also minimizes the absolute amount of shimming needed.

ZERO-PLUS: This option means all positive shimming but forces one bolt location to be zero (no correction). This is very handy when the bolt circle diameter is the same as the flange diameter, or you already have some shims between the flanges to start with and want to minimize the amount of shimming needed.

ZERO-MINUS: This solution is similar to ZERO-PLUS but in the negative direction, meaning all corrections call for removing shims, with one bolt position at zero correction. This is handy if you have lots of shims already between the flanges and want to reduce these while minimizing the corrections needed.

For the highest confidence level possible while doing predictive vibration analysis work, the location and placement of your sensor are crucially important to you. However, sensor placement is sometimes a trade-off between time, safety, and precision.

Most equipment is mounted with the shaft oriented horizontally to the ground and the analyst must decide whether to take a radial horizontal measurement, radial vertical measurement, a shaft axial measurement, or some combination of the three. If the analyst has the time, there is good reason to take all three positions. When it comes to analysis, an analyst can always choose not to view data he or she has, but can never choose to view data he or she did not collect.

Where should I place my sensor? The answer to this question should come from a focused consideration of what each possible position offers to the overall analysis effort. The fundamental consideration in placing your sensor is that the vibration signal from the component or components of interest should take the path of least resistance to the sensor. This should be coupled with thought given to how every likely defect frequency presents itself relative to direction.

Many fault diagnoses are determined, or the level of confidence enhanced, by relating one location result to another. For example, a high 1× vibration in the horizontal direction on a direct drive center-hung rotor could mean a lot of things, if taken by itself. But if this information is coupled with the additional hypothetical data below:

1. The axial vibration is also high: then possible misalignment or bent shaft becomes likelier.
2. The axial is low, but the vertical is 1-½ times as high as the horizontal: Now looseness is probable.
3. The axial is low, and the vertical is ½ of the horizontal: probable unbalance.
4.  The axial and vertical are both very low relative to the horizontal: In fact, the horizontal is 75 to 100 times the axial and vertical! Almost unquestionably there is a resonance problem.

In all of the above scenarios, a phase and visual inspection are required to deliver a truly confident diagnosis, but the directional aspect of data analysis is clearly shown.

Trending puts still further demands on the analyst by requiring each successive measurement to be taken in exactly the same place as before, to the extent possible. For parameters to be reliably trendable, operating states and data collection states need to be the same from measurement to measurement.

A real danger for the analyst using portable vibration data collectors lies in the monotonous repetition of placing a sensor hundreds of times in a day of data gathering and becoming careless when making that next placement. If feasible, routes should be kept small enough to help avoid the human factor. It’s too easy to daydream while collecting data. A route under 200 points helps keep the monotony away. The analyst should focus on both safety and data collection precision throughout each route. Happy defect hunting!

The customer needed to align a boiler feed pump to a fluid drive.

Before doing so,  we took care of the simple but often-ignored pre-alignment checks, including a thorough cleaning up of the area around the machines. The area was a mess to start with, and cleaning up allowed us to check for soft foot and start making moves immediately after taking readings, without delays.

Some of the essential clean-up and preparation tasks we performed were:

• Clean up the work area.
• Remove jacking bolt fixtures and wire brush the corrosion off them.
• Cleaning and greasing the hold-down bolts and jack bolts with white lithium grease.
• Drilled and tapped new holes in the base to add jack bolts where there weren’t any.
• Replaced dirty used shims with new precut stainless steel shims.
• Rough aligned the pump so its anchor bolts were centered in bolt holes of the feet.

This preparation work saved much time on the actual alignment, and more importantly, ensures that the next time this job must be performed the jackscrews, base, and anchor bolts will be in good condition, allowing the machines to be quickly and accurately realigned.

On a recent visit to a plant,  I came across this dial indicator with a calibration sticker.

How often are your dial indicators calibrated? You depend on them for precise 1 thousandth accurate measurements, or tighter for high accuracy dial indicators. Routine calibration inspection should be performed on any precision measurement instrument. This includes your laser shaft alignment equipment.

Here’s the calibration sticker on the back of a ROTALIGN® iS intelligent sensor. LUDECA offers state-of-the-art NIST traceable calibration inspection and certification which is recommended every two years for our laser alignment systems. Knowing that you can depend on your readings the next time you align a critical machine will give you peace of mind and reduce liability.

LUDECA’s calibration lab is a factory-authorized, NIST and NUPIC certified facility to calibrate your ROTALIGN®, OPTALIGN®, and VIBXPERT® systems in the United States. Sending your system in for calibration is fast and is just a small routine cost compared to the potential consequences of not having it done.

Can you afford to risk your machines and safety? Beware of non-authorized entities that purport to offer calibration services.

As a vibration monitoring program becomes more mature,  the number of monitoring points on a machine and throughout a facility can increase to a very high number. These additional monitoring points are required to identify potential failures and maintain a world-class reliability program. Unfortunately,  these additional measurement points usually result in an increase in the time required to complete the data acquisition (routes).
Consider using a triaxial accelerometer with a magnetic base along with a vibration analyzer such as the VibXpert® II. This combination will allow the acquisition of multiple measurement points simultaneously and guarantee that proper data is being collected. You will be able to achieve the desired results with the highest analytical accuracy and greatest labor efficiency.