Bearing Failure Analysis Using SEM

Bearings, or devices that allow constrained relative motion between parts, have a tendency to wear out prematurely. Since they are a crucial part of many mechanical operations, it is important to monitor the bearing for signs of wear and replace when needed, or remove the cause of the wear. Understanding the causes of failure can help prevent costly downtime due to mechanical failure.

Bearing failure occurs for several different reasons, including:
• Dirt (Foreign Particles)
• Misassemble
• Misalignment
• Insufficient (or Contaminated) Lubricant
• Corrosion
Since some of these will happen under normal operating conditions, the machinist must be able to monitor the bearings on the work floor.

Simply replacing the bearings, however, doesn’t always make the problem go away. In the case of dirt or contaminated oil, the new bearing would be exposed to the same circumstances that caused the old bearing to fail. Eliminating the source of the problem can extend the life of the bearings, and the machinery.

If, when inspecting the bearings for signs of wear, the mechanic finds evidence of foreign particles, the next step is often finding out where the particles are originating. The desktop SEM, Personal Scanning Electron Microscope (PSEM eXpress) by Aspex with Advanced Quality Control (AQC) software is capable of running particle analysis directly in the mechanic’s shop.

The AQC evaluates size, shape, and composition of all the particles present in a sample, allowing the mechanist to determine what particles are making it to the bearings and causing unnecessary wear. Since these particles are often on the micron-level, having a PSEM on the shop floor that can identify size and composition of these particles can save time and money: the particles are quickly identified and the source of the wear can be reduced or eliminated.

In the automotive industry, bearing failure of any kind can be catastrophic. Having the ability to analyze the cause of bearing failure is one of the first steps in implementing a solid quality control strategy. The AQC also helps prevent warranty issues in transmission and power steering assemblies, saving companies much more than the upfront cost of implementation.

While the AQC can’t prevent bearing failure, it can analyze the causes of bearing failure so that preventative steps can be taken in order to reduces the instances of failure due to contaminates. The PSEM with AQC by Aspex is a fully-automated, industrial particle analysis machine.

Reference:
Aspex, http://www.aspexcorp.com/industries/industrial-automation.html
Engine Parts, http://www.engineparts.com/publications/CL77-3-402.pdf