Doug Pauls quoted James Mitchell:

>>  I am looking for guidance on choosing gold plating thicknesses and
>>  plating processes for circuit board edge fingers.  For example: What are
>>  the recommendations for circuit board edge fingers that will be inserted
>>  into a connector and removed 10 times verses a installation/removal
>>  cycle of 50 times?

and added this:

>Along the same lines, I have an application where I mate / de-mate a connector
>hundreds of times.  I would ask the TechNet crowd which would be better, gold
>or a hard nickel?

Perhaps palladium-nickel would help. Some connector manufacturers claim the
wear performance of palladium nickel finishes is better than gold. Berg
called their finish "GXT" and Robinson-Nugent called it "Robex". Both these
companies touted the Pd-Ni as being superior to gold for wear, porosity,
cost, and I know Bellcore approved its use.

I'm not sure whether any board manufacturers use palladium-nickel, but I
think a Pd-Ni connector could be mated with a gold finger connector. If you
think you could use a nickel finger contact surface on the board
interconnection (with its higher contact resistance) then maybe the Ni
board contact with the Pd-Ni mating connector would work.

My other suggestion regarding extending the wear would be to ensure the
used of a connector lubricant on your finger contacts. The polyphenyl ether
lubricants would undoubtedly help extend the number of mating cycles, and
they can tolerate high temperatures. These are sold by Tech-Spray in felt
pen applicators.

And remember, advice is sometimes worth the price you paid.


cheers,


Jerry Cupples
Interphase Corporation
Dallas, TX USA
http://www.iphase.com

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