Using Vibration Analysis in Predictive Maintenance
June 20, 2022
Most machines vibrate when they are in operation. When you record and study the vibration pattern under specific conditions, you can identify changes in the machine’s operational behavior. This is where vibration analysis comes into play.
Vibration Analysis (VA) measures equipment vibrations to monitor the equipment condition. VA helps pinpoint abnormal vibrations, which may indicate potential issues with equipment.
Maintenance professionals use VA to identify potential breakdowns before they occur to prevent breakdowns and avoid failures.
Traditionally, manufacturers relied on corrective maintenance, where manufacturers waited until after a breakdown to repair the equipment.
Modern manufacturers use vibration analysis as a form of predictive maintenance (PdM) techniques. PdM and other preventive maintenance plans are excellent levers for efficiency and can help minimize downtime, repair costs, and overtime.
The Process of Vibration Analysis
VA is a four-step process:
- Collect vibration data: Use vibration sensors or a portable device to collect vibration signals and data from equipment.
- Start with a baseline: Collect vibration data from a machine operating with ideal characteristics. Record the vibration data to establish a baseline to compare data from other machines.
- Store vibration data: Store the vibration data so you can compare future data sets to historical data sets. You can automate this process by investing in an online monitoring system to collect vibration measurements.
- Analyze vibration data: As you collect data, compare it with the baseline to identify vibration levels, anomalies, and defects. If you find a defect, perform the necessary repairs or maintenance work to prevent machine failure and unplanned downtime.
How to Collect Data for Vibration Analysis
Now that you have an overview of the VA process, let’s discuss the physical and digital tools needed for VA.
Mountable or Portable Equipment
Fixed vibration sensors are mountable and used where it’s unsafe for technicians to reach regularly.
The most commonly used sensors are accelerometer sensors like proximity probes, piezoelectric accelerometers, laser Doppler vibrometers, and microelectromechanical sensors (MEMS).
You’ll also find vibration analysts using other types of sensors. However, the right type depends on the appropriate application. To choose the appropriate sensor, consider factors like noise, amplitude, sensitivity, mounting options, and sampling vibration frequency, among other indicators.
You also can use portable devices to collect vibration data. Portable devices are especially convenient if you run condition-based maintenance (CBM).
CBM is a form of preventive maintenance but differs from predictive maintenance.
You can use a handheld device alongside a computer maintenance management system (CMMS) to automatically collect vibration data for equipment.
How Vibration Analysis Software Works
A sensor connected to equipment collects the data. And then you need to be able to view and consolidate the data. Software for data analysis includes enDAQ Lab, Control Software (Vibration Research), and FEMtools.
You also can set up an online monitoring system. Vibration sensors send vibration data to a cloud-based monitoring system in real-time. The system monitors the data and triggers a notification when there’s a potential anomaly.
The VA software records the data. Then, it measures the time interval between each vibration pulse (i.e., frequency) and the intensity of vibration (i.e., amplitude).
A VA tool might use either or both of the following formats for recording vibration data:
Time waveform is the raw data produced by your vibration equipment. It compares the vibration’s amplitude against time to detect the presence of a defect in equipment, but not the cause. This is where the frequency spectrum can be helpful.
The Fast Fourier Transform (FFT) is an algorithm that converts the time waveform into a frequency spectrum. The frequency spectrum plots the frequency against time, detecting a broader range of potential issues with the equipment. FFT also detects the exact cause of the defect because it provides specific waveforms per equipment component.
After collecting the data, the VA tool either detects anomalies or provides the crucial data to reliability professionals for interpretation.
Training and Certification
Several institutes offer certification to ISO 18436-2 (condition monitoring and diagnostics of machines using vibration analysis). Some institutions provide courses and training relevant for reliability engineers and vibration analysts.
The following are your best options to acquire vibration analysis skills:
- The Vibration Institute: The ANSI-recognized Vibration Institute offers a Vibration Analyst certification with four levels. Each level requires a specific number of training hours.
- Technical Associates of Charlotte: Technical Associates of Charlotte is a world-leading vibration training and certification provider.
- Mobius Institute: Mobius Institute offers vibration analysis certifications and training in other areas like condition monitoring.
- American Society for Nondestructive Testing (ANST): ANST is a leading accrediting institute for reliability engineers interested in nondestructive testing. Unlike other institutes on the list, ASNT isn’t entirely focused on vibration analysis but includes it in the coursework.
Identifying and addressing potential failures before they turn into real problems saves money. Preventive maintenance techniques like vibration analysis give you a time buffer, allowing you to strategically plan maintenance and prevent failure.
Once you’ve identified a potential issue with vibration analysis, you can create a work order in a CMMS like MaintainX. If a part requires replacement or service, you can assign the task to a technician via MaintainX.
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