M120-55780 Dummy Seal For Use With Compact Type Low-Profiled Waterproof Connector

Fretting wear: Fretting is a wear phenomenon that occurs on two surfaces with small vibrations in relative motion, with an amplitude of 1-100um, mainly due to thermal expansion and contraction caused by temperature cycles and background vibrations, automotive connectors Because of the simultaneous existence of vibration and thermal shock in the working conditions, fretting occurs frequently. For example, if the electrical connector fluctuates at 5°C/h and cycles 20 times, the thermal expansion coefficient of the contact pin (made of brass) is 2x10-5/°C, and the length of the contact pin is 5mm, then the micro-vibration amplitude can reach 5um. Tests have shown that after such microvibrations reach millions of times, it may seriously affect the reliability of electrical contacts. For example, when a car runs for 5 hours, the vibration frequency is 1000Hz, which is equivalent to 18 million microvibrations.

Micheal Bryant of the United States proposed the following fretting failure model in 1994, which divided the failure into seven stages.

(1) Contact of clean microscopic protrusions;

(2) The micro-vibration movement exposes the microscopic protrusions to the action of corrosion, forming a corrosion film;

(3) The reverse movement of micro-vibration scrapes the film layer, part of it falls into the "valley", and part of it is pressed into contact part;

(4) One-step micro-vibration again exposes the contact part to corrosion;

(5) The micro-vibration movement causes the microscopic protrusions to produce plastic deformation, breaks the rust film layer, and makes the debris and protrusions Metal mix;

(6) The microscopic protrusions are gradually polluted by rust, and the contact resistance increases;

(7) Finally, the rust debris fills the "valley", forming an insulating layer with a thickness of at least 20nm between the two contact surfaces, and the connection fails completely.

Simple instructions：

We have product Catalogue，please contact us on skype，WhatsApp or Email.

If you can't find a product on our website or catalog, We deal with over 10,000 items, our catalog doesn’t cover all products. And we are developing 100+ molds yearly, which means around 10 new products are created in our factory. So don’t go away, just send us your photo or part no, we’ll check for you.