Brian,
Drilled hole size is no-doubt, far-and-away the #1 cause of c-pin deformation problems.  Ideally the drill and maximum drill wear should be defined.  In most cases you cannot allow the fabricator to substitute imperial for metric.  Be careful not to get yourself in a double toleranced contractual nightmare:  bigger hole with lots of Cu generally works well, but if the fabricator is allowed to choose, they will pick little hole with little Cu.
Also be aware that the fabricator will measure copper thickness as the industry standard 3 points per side average, which in some cases does not adequately describe the thickness/finished diameter in the working area.
For verification, from our experience, pin gauging and vertical sections are too uncertain.  Horizontal sections work well.

Speed/alignment/ and resultant force should be suspects too.  

Chris



-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of David D. Hillman
Sent: Thursday, September 10, 2009 9:53 AM
To: [log in to unmask]
Subject: Re: [TN] PTH Cracking with NiAu and Compliant Pin

Hi Brian - the primary cause of plated thru hole cracking using ENIG surface finishes and press-fit/compliant pin technology is incorrect plated thru hole size due to: (a) incorrect fabrication of the plated thru hole; (b) incorrect nickel plating of the plated thru hole; (3) incorrect design dimensioning/tolerancing of the plated thru hole. A secondary cause of plated thru hole cracking would be improper installation force/alignment of the press-fit/compliant pin devices.  If I get a chance, I'll see if I can find the technical article references in our database.

Dave Hillman
Rockwell Collins
[log in to unmask]




Brian Chandler <[log in to unmask]> Sent by: TechNet <[log in to unmask]>
09/10/2009 06:42 AM
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Subject
[TN] PTH Cracking with NiAu and Compliant Pin






Does anyone have any experience or articles with PTH cracking when using
NiAu board finish with compliant pin? I saw some articles about it a few
years ago but I cannot find them now. 

Thanks in advance,

Brian

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