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| Date: | Thu, 2 Nov 2006 12:11:46 -0600 |
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Irving,
I've have been through several fluxes so far. Your best bet is something
with a small amount of rosin to give the flux enough time on the wave.
Currently I have a water based no-clean flux with a small amount of rosin
that is working real well on test boards. With regards to trying other
surface finishes. There was a paper at SMTAI 06 that mentioned SnCuNi as
a surface finish and it had similar erosion traits as SnPb you might want
to look into that but you would have to weigh the issues.
Best regards,
CP
To: <[log in to unmask]>, <[log in to unmask]>
cc:
Subject: RE: [TN] Copper Dissolution
Corey,
Thanks. It is very worth recommendation. What kind of flux type you
recommend ?
ENIG is not allowed by our customers, we may need to try other finishing
types .
Irving
-----Original Message-----
From: Corey A Peterson [mailto:[log in to unmask]]
Sent: Thursday, November 02, 2006 11:55 PM
To: TechNet E-Mail Forum; Lee, Irving (§õ©ú©ô TAO)
Subject: Re: [TN] Copper Dissolution
Irving ,
There are several options here.
1) Use an ENIG surface finish
2) Use a flux that is a bit more aggressive probably will need some rosin
to give it enough legs" to last in the wave that long. Avoid using the
chip wave if possibly. You are going to be hard pressed to find a flux
that will last that long thru the wave solder pot.
3) Specific minimum copper thickness for the knee
4) Change solder pot to a less aggressive solder alloy
5) Use the best thermal mitigation strategies and where possibly use
bigger annular rings.
Corey Peterson
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Subject: [TN] Copper Dissolution
How to avoid copper dissolution during lead free wave soldering ?
[1] Printed Circuit Board Size : 13"x16" , Thickness : 0.93"
[2] Lead Free Solder Bar Type : SAC = Sn + 3 % Ag + 0.5 % Cu [3] Both
sides Reflow prior to Wave Soldering [4] Wave time : 6 sec , Temperature :
265 degree C
Irving Lee
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