How Vibration Analysis Helps You Avoid Costly Downtime

What is Vibration Analysis?

Vibration analysis is the process of assessing a machine’s performance using nothing but the rumbles and sounds of its vibrations. You then analyze the oscillations and peaks while the machine is running to gain deeper insights into its condition. This requires tools like accelerometers and vibration analyzers to perform Fast Fourier Transform (FFT) analysis—a method that breaks down the machine’s vibrations into individual frequencies.

Importance

Just like how a person might start coughing when they’re coming down with something, machines give off unusual vibrations when something’s not right. These vibrations don’t match their normal, steady, forced vibration. In some cases, these abnormal vibrations can hit the machine’s natural frequency, causing resonance, which makes the shaking even worse.

If these spinning parts aren’t properly diagnosed, machines like heavy equipment used in construction or similar work could malfunction and cause costly repairs or even workplace accidents in the long run. Vibration analysis is a key part of machine maintenance and equipment maintenance, helping you catch problems before they turn into serious issues.

When tracking changes in vibration, you need to take note of these three things:

1. Amplitude – This is how strong the vibration is. It can be measured in terms of displacement, velocity, or acceleration.

2. Frequency – This pertains to how often a machine vibrates back and forth in a full cycle. It’s measured in Hertz (Hz) or Cycle Per Minute (CPM).

3. Phase – This refers to the timing between vibrations, specifically, how the vibration at one point on a machine relates in time to vibrations at another point.

How To Conduct Vibration Analysis

Getting Started with Vibration Analysis

Vibrational analysis is considered a must when working with or alongside machines. There are too many benefits not to ignore like preventive maintenance, cost savings, and operational safety. In fact, as per US Department of Energy, predictive maintenance with vibration analysis can save between 8% to 12% compared to standard preventive maintenance, and up to 40% compared to reactive maintenance approaches.

Follow these steps to get started:

1. Identify Assets – Take note of which machines you need to monitor on a daily basis. These could be your regular machines that are necessary to your company, or ones used for specific tasks only.

2. Set a Baseline – Get an initial reading of the machine at its most optimal state. Then, record its details (such as speed, temperature, etc.) and history for future reference.

3. Prep Equipment – Ready vibration-reading materials and monitoring devices for use. Vibration sensory tools such as  accelerometers, velocity sensors, and displacement sensors are ideal for this, and, once you’ve chosen the right one for your needs, properly place them in a location where the vibration is strongest.

4. Conduct Readings – Let the sensor run with the machine from startup to shutdown for the full picture. Continuously monitor for the extremely vital readings and findings.

5. Analyze Data – Gather collected data into a cloud-based system to easily access them and share them. You need a Data Acquisition System (DAS) and a vibration analysis software to collect all the data and convert these waves into digital values.

6. Take Action – Study the data and take the necessary actions based on the analysis done. This can include scheduling maintenance, buying spare parts, performing condition-based maintenance, and contacting manufacturers or repairmen, as needed.

How To Read The Raw Data

Reading vibrations through waveforms can be converted to digital data by software, but it’s also great to have an understanding of what these frequencies mean. The best way to read the data is with frequency domain analysis, which uses FFT. FFT breaks down a vibration signal into individual sine waves (the waves), revealing the strength of each frequency in the spectrum plot (the graph).

In the spectrum plot, along with all the frequency data, there are two axes:

• X-Axis – Represents frequency and is usually labeled as Hz or CPM based on the machine’s multiples of running speed (harmonics).

  • 1X – Represents the fundamental running speed of the machine with a low risk of misalignment

  • 2X – Often indicates misalignment, particularly angular misalignment

  • 3X and 4X – Can suggest mechanical looseness or other mechanical issues

• Y-Axis – Represents amplitude, which shows the intensity or strength of each frequency. Larger peaks, or new, unexpected ones, can signal potential mechanical issues.

In general, a well-maintained machine will show low amplitude at 1X (its running speed). However, when there’s imbalance or misalignment, you’ll often see higher amplitude spikes at 1X, especially if the machine is under load or operating inefficiently.

Best Use Cases for Vibration Analysis Per Industry

Vibration analysis is valuable in any industry that uses machines. It doesn’t have to be overly complex ones like turbines or conveyor belts, it can also be used in ceiling fans and washing machines. Here are some of the best use cases for vibration analysis:

Manufacturing

Vibration analysis is heavily used in manufacturing. This is because of the amount of heavy equipment present with motors, gearboxes, rotors, Computer Numerical Control (CNC) machines, and compressors involved in various manufacturing processes. The use of predictive maintenance is also important to prevent workplace accidents or downtime.

Construction

The construction industry is very accident-prone, so much so that in 2022, construction workers 1,056 fatalities on the job. Heavy-duty equipment like excavators, bulldozers, cranes, and even smaller ones like electrical drills all need to be analyzed thoroughly. Vibrational analysis also helps in staying in compliance with US Occupational Safety and Health (OSHA) Standards and workplace safety.

Transportation

If you work in transportation, monitoring your fleets’ health is essential since they are your number one asset. Whether you’re transporting by plane, train, boat, or truck; their engines, transmissions, suspensions, landing gear, and more all need to be checked at all times. The vibrational sensors can also be used to track your vehicles. Transportational infrastructure like railroads and bridges also need a lot of vibration monitoring.

Healthcare

When your main focus is to save lives, making sure that your medical devices are well-maintained is a must. Vibrational analysis is critical in testing sensitive medical devices such as MRI machines, ultrasound equipment, ventilators, and implantable devices. It also helps you stay in compliance with ISO 13485 and ISO 14971:2019 when it comes to managing risks and maintaining critical medical devices.