>     TO: IPC TECHNET SUBSCRIBERS;
>
>     HIGH RELIABILITY COMMUNICATION SYSTEMS REQUIRE LUBRICATION OF
>     CONNECTORS AND SOCKETS TO PREVENT THE BUILDUP OF CONTACT RESISTANCE BY
>     FRETTING CORROSION. LUBRICANTS FOR THIS PURPOSE ARE READILY AVAILABLE
>     AND CAN BE SPRAYED, DIPPED OR BRUSHED ONTO THE CONTACT SURFACES.
>     IS ANYONE AWARE OF EQUIPMENT MADE SPECIFICALLY TO AUTOMATE ANY OF
>     THESE METHODS?  YOUR INPUT IS APPRECIATED. [log in to unmask]


I thought the use of good gold-plate connectors completely solved this
problem. Can anyone else confirm or deny this?

In my understanding fretting corrosion is associated only with "tinned"
mating surfaces on connectors, accelerated by relative movement of the
surfaces caused by vibration or thermal cycling.

I believe that the corrosion mechanism is for microscopic "balls" of
insulating black tin oxide (stannic) to form on the surface(s). Lubricants
reduce friction and exclude oxygen, preventing the oxidation.

My solution so far for high reliability telecomms systems has been to
recommend gold-plate connectors, so if I'm right on this the expense of
applying lubricant has to be traded off on the cost-saving on connectors.

Regards,



-- 
Terry Davey,  Reliability Engineer,
European Development Engineering (108),
Motorola Ltd, GSM Products Division,         	Tel: +44 1793 545390               
16 Euro Way,                           (switchboard:          541541)    
Blagrove, Swindon,                           	Fax: +44 1793 541228      
England, SN5 8YQ.                            E-mail: [log in to unmask]    

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"Forget all this stuff about reliability - if it plugs in it's trouble." - Anon.
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