Kerry,

Initially, I don't see a problem with this. The JG-PP / JCAA Lead Free
Soldering Program used FR-4 with Tg = 170C and the boards came out fine.
I built hardware with boards having a lower Tg and they came out ok. I
acknowledge that the boards I processed were stored in a drybox prior to
use, to minimize the possibility of moisture entrapment which could lead
to board delamination.

I recommended the ENIG finish and you're using that.

What alloy are you thinking about using? From my experience, using Tin
Silver Copper (SAC-305), my peak reflow soldering temperature was in the
240C - 250C range in air and in nitrogen - nitrogen will improve wetting
and reduce the amount of solder residues. Of course, if you have a heavy
board with a large thermal mass, you might have to get that high in
temperature.

If you have any additional questions, contact me offline.

Hope this helps.

Good Luck.

Lee Whiteman
Senior Manufacturing Engineer
American Competitiveness Institute
E-Mail: [log in to unmask]
Ph: (610) 362-1200 x208
Fax: (610) 362-1290

This message is for informational purposes only and does not supersede,
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message does not bind ACI or its affiliates to any commitment, either
express or implied, unless ratified in writing by an authorized
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-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Kerry McMullen
Sent: Wednesday, May 11, 2005 1:03 PM
To: [log in to unmask]
Subject: [TN] FR406 Tg 175 Degrees C - Lead Free Processing


Hi TechNetters

Can I use FR406 175 Degrees C laminate during a lead free assembly
process where the reflow temp will be around 260 Degrees C. ? The boards
will be ENIG.  Any disadvantages.

I know there was a thread, but I can't find it.

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