Hi Louis - I am in agreement with George Wenger, on ENIG you are soldering 
to the nickel plating and not the copper plating. Unless the nickel 
plating was impacted by a copper plating condition (i.e. porosity, 
adhesion, etc.), it is not clear why the nickel wouldn't be the 
controlling surface impacting solderability. What solderability test 
results led you to suspect the copper plating is playing a role in your 
float tests?

Dave Hillman
Rockwell Collins
[log in to unmask]




From:   Louis Hart <[log in to unmask]>
To:     <[log in to unmask]>
Date:   05/31/2013 02:19 PM
Subject:        [TN] solderability factors
Sent by:        TechNet <[log in to unmask]>



TechNetters, In concert with colleagues, I have been conducting 
experiments to identify and assess the relative influence of some process 
factors and parameters on the performance of printed circuit boards with 
ENIG final finish in the J-STD-003B solder float test of S coupons.

These experiments have led me to conclude, or at least suspect, that the 
plated copper, on which the ENIG is deposited, has a highly significant 
impact on performance in the solder float test.

We have a DC copper plating line along with a Reverse Pulse copper plating 
line. Experimental results show significant difference in solder float 
testing between the lines. I had been looking at the book by Humpston and 
Jacobsen, Principles of Soldering, after having spent some time with the 
TechNet-referenced books by Manko and Klein-Wassink.

Humpston and Jacobsen's book, in the 2nd of the two chapters I read so 
far, appears to say plating technique can affect solderability. Maybe I'm 
misinterpreting something, since I'm often reading these things around 11 
PM.

Anyone in the TechNet world able to help me understand if and how DC 
copper might solder differently from Reverse Pulse copper, after ENIG 
deposition?

Louis Hart
Compunetics
Monroeville, PA
USA
[log in to unmask]<mailto:[log in to unmask]>
412-858-1232


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