Types of Common Misalignment: How to Recognise & Fix Them

RMS Common Misalignment Steven Whittle

What are common types of Misalignment?

30-second summary

  • Common misalignments are usual and can happen to machines in a variety of ways.
  • Left alone misalignment can reduce the longevity of bearings, shafts, seals, and even couplings.
  • Misalignment is the root cause of most machine breakdowns: bearing failures, and damaged seals, shafts, and couplings.
  • It is widely believed that 50% of machine failures are due to misalignment.
  • Treating the misalignment early on, whether by a soft-foot correction, dial indicator alterations or a full-fledged laser alignment, will help to prevent total machine failure.
  • The basic rule of thumb is, machines that are precision aligned will function for a longer period and costs less to run.

How does misalignment occur?

Common misalignments are the result of two rotating shafts not parallel to one another, either by a slightly offset or angled gap at the coupling. However, sometimes in most real-life situations it is both, which is called a compound misalignment. There are several causes for misalignment:

  • Pipe strain
  • Thermal expansion
  • Human error
  • Wear causing sheave to deform
  • Baseplate settles irregular to form a ‘soft-footing’
  • Inaccurate assembly of components, such as motors and pumps.

The primary point to remember is that any unsteady motion or movement to shaft centrelines that goes against the intended motion of the machine can cause bearing or couplings to be stressed, and the seals to undergo damage in need of immediate repair.

The Laser Alignment course is ideal if want to improve your knowledge of shaft alignment. This is one-or-two-day Onsite course. It includes a walk-through of the alignment benefits and methods, as well as hands-on exercises – your understanding and appreciation of shaft alignment will skyrocket!

Five types of common misalignment

1. Parallel misalignment

This occurs when two shafts (or sheaves) do not exist on a parallel plane—while their centrelines may be parallel to one another, the actual centreline is offset.

2. Horizontal angle misalignment

This occurs when the angle of one shaft is different to the angle of the other on a horizontal plane.

3. Vertical angle misalignment

This occurs when the angle of one shaft is different to the angle of the other on a vertical plane.

4. Horizontal angled and offset misalignment

This is a compound misalignment that occurs when one shaft is both offset and angled differently than the other shaft along a horizontal plane.

5. Vertical angled and offset misalignment

This is a compound misalignment that occurs when one shaft is both offset and angled differently than the other shaft along a vertical plane.

How best to recognise and detect common misalignment?

While it is important to understand the root causes of misalignment and the most basic forms in which it occurs, the most important thing to know is how to recognize misalignment before it reduces the life of bearings, seals, shafts and couplings. As mentioned, a properly precision aligned machine will run more effectively and last longer, therefore the detection of misalignment is often best ascribed as a form of preventative maintenance, rather than a reactive resolution.

The AMS 2140 Machinery Health Analyser coupled with the AMS 8240 sensALIGN laser fixtures makes for a powerful combo-package that can help rectify misalignment issues easily.

How to detect shaft speed using a SpeedVue laser

With that in mind, there are five primary methods used to detect common misalignment:

1. Misalignment detection technique: Thermography

Becoming increasingly popular for its ability to recognise misalignment easily in machines, especially in belt drive applications. A clear indication of misalignment is an increase in friction as the offset or angular shafts are likely pulling against one another ever so slightly more. This, in turn, increases the temperature of the machine at the problem area.

The job of thermal-imagery, then, is to measure these hot-spots and determine exactly where the problem is occurring or beginning to occur. Thermography is a secondary indicator as when there is an increase in temperature damage is being caused mechanically.

2. Misalignment detection technique: Vibration analysis

Vibration analysis is effective at assessing the micro-vibrations of a machine and noting when it approaches or exceeds acceptable parameters. These minute observations can be used proactively, just as thermography, to recognise an issue with misalignment and stop it before the bearings or belts wear down to catastrophic levels. As the variables of those micro-vibration increases can vary by degree and complexity, often a result of some things more than only misalignment, imbalance or looseness overtime, the analysis is conducted using Accelerometers and correct sampling for the expected failure mode predictor. An important aspect of vibration analysis is phase analysis used to diagnose and pinpoint the type of misalignment early on. All these tools of measure help the analyst to determine exactly what is causing the disruption or how to prevent it escalating.

3. Misalignment detection technique: Oil analysis

One of the more complicated measures to determine common misalignment, oil analysis is a process by which an analyst can measure misalignment through the general wear-and-tear on contaminants in oil of the machine. While specialists are often required to conduct a proper oil analysis, its results often are not as effective for preventative maintenance with misalignment.

4. Misalignment detection technique: Laser shaft analysis

Likely the most common of all forms of misalignment checks, laser shaft alignment systems can accurately calculate the degree to which a coupling may be offset and allows for an accurate measure of remedy to get it along an even plane. Precision Laser alignment results can be greatly affected by operator experience and training.

5. Misalignment detection technique: Motion Amplification

This is the easiest of user’s interfaces to visually diagnose misalignment and also to visually see the rout cause of the misalignment. You do not need to be experienced or an engineer to view a motion amplification video so see there is misalignment.

Recent example: Iris M™ with the new Tach Sync

Pump base problem visualised

Our experienced vibration analysts can help recognise and fix common misalignment for your machines.

How to correct common misalignments?

The good news is that the hardest part of misalignment is determining where it exists for how long it has existed. The solutions to misalignment vary from simple to complex. Often it can be replacing bearings, belts, or couplings and other times those pieces are in good enough shape that all that is needed is a ‘soft-footed’ correction or slight alignment correction. If a misalignment has gone on for too long unnoticed, it might be the reason that the machine is beyond repair. On the other hand, preventative maintenance and scheduled misalignment analysis can help to ensure machine’s longevity, improve energy efficiency, maximize output, and overall save money by mitigating problems before they move beyond repair.

Common misalignment issues are a topic on the Vibration Analysis CAT-II course. This is ideal for those who been performing vibration analysis for more than twelve months and have a good understanding of the fundamentals.

Gallery images

Precision Shaft Alignment is a learning topic within the iLearnReliability Condition Monitoring software. It is intended for anyone wanting to further their understanding of monitoring, diagnostics and precision maintenance to support increased plant reliability.

If you have any questions about common misalignment in maintenance and how Reliability Maintenance Solutions can help you, please feel free to contact us or leave a comment below.

FAQs on common misalignments

Of the different methods available, Laser alignment is the most accurate method. Laser alignment uses lasers to determine the exact shaft position but is very dependent on user experience in the process of precision alignment.

Measuring different sections along the horizontal and vertical planes will help determine shaft misalignment and whether the misalignment is angular, parallel, or often both. Phase analysis offers the most precises diagnose of misalignment.

When installing bearings be aware that common misalignment can often occur. Ensure that the housing is rigid to best ensure support for the bearing.

Last updated: 20th July 2024

11 replies
  1. Taylor Hicken
    Taylor Hicken says:

    I appreciated it when you shared that it is important to detect any misalignment before it reduces the life of bearings, seals, shafts, and couplings of the system. It is imperative to look for a reliable service that can help provide the necessary replacement parts. I would like to think if a company has a broken shaft or bearing, it should consider getting a new one from a reliable supplier.

  2. Calum S
    Calum S says:

    The iLearnReliability Condition Monitoring software has a learning subject called Precision Shaft Alignment. It’s for anyone who wants to learn more about monitoring, diagnostics, and precision maintenance in order to improve plant reliability. Thank you so much!

  3. Frederic N
    Frederic N says:

    Thank you for sharing superb information. Your web-site is very cool. I am impressed by the details, it reveals how nicely you understand this subject. Bookmarked, will come back for extra articles.

  4. Morris
    Morris says:

    I wanted to thank you for this fantastic read!! I absolutely loved every bit of it. I have you bookmarked to check out new things you post…

  5. Iris Smith
    Iris Smith says:

    Thank you for pointing out that one of the trickier methods to identify frequent misalignment is oil analysis. Using this method, an analyst can measure misalignment by examining impurities in the machine’s oil that have been subjected to regular wear and tear. My husband is employed by an automobile business. I’ll advise him to have an automobile durability consultant look over his vehicle, particularly the oil analysis.


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