Electrical Terminal Fretting Wear Test

This test equipment and test method is unique to Nye Lubricants. It was designed and built by our Application Design and Validation Testing (ADVT) lab. Fretting wear refers to a mechanical and chemical wear mechanism where the sliding contact between two surfaces creates wear, which becomes oxidised. This process continues at an exponentially higher rate once oxidised wear particles are created. The failure mechanism occurs when enough oxidised wear debris has been created and the contact resistance increases to a level where continuity in the contact is lost.

Fretting wear is one of the major forms of deterioration and failure in a variety of industries, including Automotive, Aerospace, and Consumer Electronics. Research has shown that over 60% of the electric problems in cars are directly related to fretting wear. There are many well-known applications that experience fretting, including engine bearings on a diesel engine that is left idling, slot mounted server boards that are not isolated from vibration, and electrical connector harnesses in a taillight. A contact lubricant provides a thin film that separates the moving surfaces and reduces the coefficient of friction, while also sealing the contact surfaces and preventing oxidative wear particles from forming. This leads to a significantly increased life over bare terminals.

The fretting wear test apparatus designed by Nye’s ADVT team is based upon a magnetic linear actuator which operates using the Lorentz Force Law. This actuator produces oscillations in a frequency range of 1Hz to 1,000Hz, amplitudes of 1-200μm, and with a continuous load of 50lbs and 150lbs of peak force. To ensure accurate position control, an absolute encoder is utilised for closed loop motion control to keep the amplitude resolution within 1 μm.

With this new fretting test methodology and apparatus, we can determine the durability and reliability of our lubricants. Through the testing of lubricants to their ultimate fretting failure point, we can look forward to helping our customers design systems that are optimised with a lubricant to reduce or eliminate fretting failures. This can lead to a reduction in the warrantee and safety issues seen in many industries, like automotive.

Take a look at our other fretting related articles by clicking on the fretting tag on the sidebar.

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