Hi Richard - yes, you can use an immersion silver pwb surface finish with 
a press fit connector. Two primary areas of importance; (1) team with the 
connector fabricator and make sure that the plated thru hole is designed 
specifically for the press fit connector you are going to use. In the days 
of tin/lead surface finishes, the tin/lead surface finish behaved somewhat 
like a "lubricant" during pin insertion. The immersion finish families 
(ImAg, ImSn, ENIG, ENEPIG,) are not as forgiving thus you need to may more 
due diligence to getting the plated thru hole specified accurately; (2) to 
what extent is the press fit connector going to be exposed to the use 
environment and what kind of use environment is it? As Lee Parker 
detailed, OSP/bare copper can be a very reliable under a variety of use 
environment exposures. If you are enclosed in a metal housing and you are 
using a conformal coating, then you are pretty robust to many use 
environments.  Rockwell Collins is using press fit connectors in a number 
of use environments (both military and commercial) successfully. Just need 
to do some homework as part of the early design process. Good Luck.

Dave Hillman
Rockwell Collins
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[TN] Using Pressfit connectors on an Immersion Silver PWB






Has anyone experienced any issues with using pressfit connectors on a
circuit board that has Immersion silver finish? Do I need to worry about
any tarnishing inside the pressfit connector holes? Since there will be
no solder, the holes will remain open, and thus I was wondering if there
have been any issues with this.

I am considering using immersion silver as a finish for a high
reliability design, and I have never had issues using it with thousands
of medical and military and other applications, including
telecommunication blades where pressfit connectors were used. However,
this is a military application, and I want to know if there are any
potential issues before I commit to using it for this application. 


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