How Vibration Analysis Helps to Detect Bearing Wear
Bearings play a vital role in the performance of rotating equipment. Ensuring the health of them is an important part of any maintenance & reliability program. This article will discuss one type of bearing defect category and how vibration analysis can help to detect bearing issues well ahead of when the bearings fail.
What is Bearing Wear?
Bearing wear is a broad-based term that refers to any condition in which a bearing has material worn away from the bearing surfaces due to sub-optimal operating or maintenance practices. The lost bearing material can be on the inner or outer races, on the rolling components, or any of the parts that make up the separators between the rolling elements.
What are the common causes of Bearing Wear?
Bearing wear can be caused by a variety of factors. Below is a list of the most common types:
- Inadequate design
- Specifying bearings that are not rated for the application or their designated operating environment
- Poor storage conditions
- Storage of bearings with methods that introduce contamination or premature damage to the surfaces or seals (false brinelling as an example)
- Improper Installation
- Using techniques that damage the bearing or how they fit into the equipment
- Substandard lubrication practices
- Over or under lubrication, using improper lubricate, or introducing contaminants into the bearing that start the degradation process
- Running outside the design window for the bearing
- Overloading the bearing outside their design window and shortening their functional life
How does Vibration Analysis detect it?
Vibration analysis can start to detect early bearing wear by detecting high-frequency noise from the bearings. As the wear increases, vibration analysis will trend the increase in the amplitude of the defect frequencies. Monitoring this trend will help the site team to make a determination of the severity and type of defect. Below is information from the Technical Associates of Charlotte that details how this works in rolling element bearings.
Journal bearings also exhibit a unique vibration signature and different types of wear patterns can be determined based on the frequency of the vibration signature collected. Below is information from the Technical Associates of Charlotte that details how this works in journal bearings.
How does Vibration Analysis help to mitigate bearing wear issues?
- Implement a condition monitoring program to track the overall health of bearings and identify when defect conditions occur. Start collecting data from a vibration monitoring system to point out acute problems and systemic machine health issues.
- Vibration frequencies can detect lubrication-related defects. Use this data to implement precision lubrication practices with steps to ensure the correct lubrication for the application is added at the time the bearings need it and in the correct amounts. Using tools like vibration and ultrasound can help to ensure the application is done correctly. Connect with lubrication service providers to upskill technicians if a systemic lubrication issue is identified.
- Collective vibration data can identify areas where systemic issues are present across machine types and areas of the site. These systemic issues can be related to the skills of the people performing the work or the tools that are being used. Improve the skills of the team members performing the installation of the bearings as an example. Provide the correct tools for the job and create best practice documentation for each type of bearing installation. Also, implement a precision alignment program to ensure that equipment is aligned correctly and not adding unnecessary load to bearings.
- Vibration analysis can highlight mechanical defects in bearings due to overloading of the equipment. Using this data, work with the design engineers or the OEM and the operating teams to design and operate the equipment inside the designated windows. When deciding on operating parameters and changes to them, involve the broader team to identify risks to the equipment's health.
- Review the storage practices of bearings in the storeroom. Ensure bearings are stored in a way that prevents damage. Implement a First-In-First-Out (FIFO) process of inventory management to make sure that bearings aren’t sitting on the shelf longer than required. Prohibit the opening of bearing packages to limit the chances of contamination. Review usage levels and adjust bearing safety stock levels to ensure the least possible amount of bearings are kept on hand for normal operation and usage.
Summary
Bearing health is a critical part of the overall health of any machine and production process. Utilizing vibration analysis to identify defects should be an integral part of any maintenance & reliability program. This enables the maintenance team to resolve the bearing issue in a planned and safe manner.
Utilizing best practices for the design, storage, operation, and maintenance of the equipment, and specifically the bearings will help to ensure defects are not introduced into the bearings and shorten their designed life. Using vibration analysis data can help to improve these best practices and continuously improve the health of the equipment and its bearings.
