Although I can not offer sources for bag sealers, I will offer a word of
warning regarding bags in general. Depending on your subsequent
processes, (i.e. soldering, wire bonding) plastic bags can and do have
the potential of contaminating your board surface, (especially if you
plan on using anti-stat bags).
Bill C.
Advanced Manufacturing Engineer
NorLux Corp.
[log in to unmask]
P.S. You might try contacting Northrop Grumman, Rolling Meadows Site
PWB Department who does use a bagging process on finished boards for
their input. I can give you names if you want to contact me directly. (I
spent 15+ yrs at that facility).
-----Original Message-----
From: Lambert, Katherine A.
[mailto:[log in to unmask]]
Sent: Tuesday, December 18, 2001 9:36 AM
To: [log in to unmask]
Subject: [TN] Board baking & sealable bags
Hi folks,
Currently we bake our boards and store them in nitrogen cabinets until
we
are ready to use the boards on our automated line. Typically, turn
around
is fairly quick - within a week - but occasionally is more than a month
due
to other part shortages.
We are trying to streamline the process a bit and get rid of the
nitrogen
cabinets as they take up a lot of space, and the boards become separated
from the rest of the kit, etc.
We are looking at a bake & bag process. We would bake the boards, seal
them
in appropriate bags with a humidity indicator card, and send them to the
assembly area with the rest of the kit. Desiccants are not an option as
they typically have caused our panelized boards to break. We have a
variety
of board types - polyimide, epoxy-glass, etc. Since the folks around
here
like a one-size-fits-all process, we need to develop the process around
the
most sensitive board type.
Now for the questions:
1. Where is a good source for information regarding sealable or
resealable
bags that are reasonably impermeable to ambient humidity? Our relative
humidity levels typically run between 30% & 50%
2. We have a bag sealer, but will a zip-lock type bag work just as well?
3. Where is a good source for information regarding humidity indicator
cards?
4. Is there any reliable information regarding how long a baked board
can be
exposed to ambient humidity before it has to be rebaked?
Thanks for any insight you can provide.
Kathie Lambert
Process Engineer
Northrop Grumman
Baltimore, MD
410-765-9746
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