Seems to indicate a problem with the board itself, possibly the material
or mat'l processing by the fab vendor. Assume this is multilayer board,
therefore if lower Tg or Td, material may not survive multiple passes
through 245C+ reflow temps without damage or degradation.
Have you had success with any other lead-free assy's, or is this your
first one? What was max oven temp?
Roger
-----Original Message-----
From: Leadfree [mailto:[log in to unmask]] On Behalf Of DeGenova, Jon R.
Sent: Friday, October 27, 2006 2:19 PM
To: [log in to unmask]
Subject: [LF] Lead free parts falling off boards
We have some PCB assemblies, measuring approximately 11x13 inches in
size, .062" thick, with very dense population on both sides. They are
mostly SMT, including about 3 BGAs. These ran fine on as leaded boards,
but in our first runs using a lead-free process and an ENIG board finish
we're seeing a strange problem. Reports are that parts are 'falling
off', not in large numbers, but enough to raise an eyebrow. Mostly
these are passives that are coming off after a double reflow process
(there was no wave soldering done on the boards at the point that this
was noticed). And in some cases, the entire PAD was coming up off the
circuit board. Has anyone seen similar issues? I'd like to give our
assembly personnel some advice on where to start investigating.
Thanks,
Jon DeGenova
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