IPC-HDBK-001 has the information. There is no consensus on the "adivce"
in the handbook so, its not a standard. My own experience has been that
you may get away without bake. But, if you are in a situation where risk
from damage cannot be tolerated you should bake. You will only find out
when you need to bake after the board is scrap.

> -----Original Message-----
> From: TechNet [mailto:[log in to unmask]] On Behalf Of Steve MacDonald
> Sent: Tuesday, February 11, 2003 3:12 PM
> To: [log in to unmask]
> Subject: Re: [TN] Moisture in Raw Boards
>
>
> Hi Dale,
>
> We've seen them sit for three or four years without an issue.
>  It's usually obsolete technology before we even get that far
> in most cases.  I can't quote a spec for it because I have
> never had a need to find one, but the absence of one may be
> intuitive in and of itself.  (I am sure if there is a spec-TN
> will produce it shortly.)
>
> None of our customers--who keep stock--have reported any
> issues to us either.
>
> Not much help, I'm sure.
>
> Good luck,
>
> Steve M.
> Quality Assurance Manager
>
> ----- Original Message -----
> From: "Dale Ritzen" <[log in to unmask]>
> To: <[log in to unmask]>
> Sent: Tuesday, February 11, 2003 14:51
> Subject: [TN] Moisture in Raw Boards
>
>
> > I, and our board suppliers, have looked through IPC-6011,
> 6012, 600,
> > 610
> and
> > most of the other pertinent standards and cannot find an answer to
> > this
> > question:
> >
> > How long should multi-layer printed circuit boards be left out in a
> > controlled ambient environment (standard factory
> temp/humidity) before
> > pre-baking the boards becomes necessary to dry out any accumulated
> moisture
> > in them? We would like to minimize potential board
> delamination due to
> > trapped moisture in the FR4 or polyamide layers (which can expand
> > rapidly when the board is placed through a reflow oven or solder
> > wave).
> >
> > Does anyone want to wade in on this one? We have identified
> a standard
> > for pre-baking IC components before use in this type of high-heat
> > environment, but cannot find any standard or specification
> pertaining
> > directly to PCBs themselves. I suspect it will have to take into
> > account the material used, number of layers, the definition of
> > "standard factory temp/humidity" and other things related
> to the board
> > and the environment it is stored in
> prior
> > to use.
> >
> > Any help in this regard would be appreciated.
> >
> > Thanks!
> > Dale Ritzen
> > Quality Manager
> > Austin Manufacturing Services
> > 9715A Burnet Road,  Suite 500
> > Austin, TX  78758

---------------------------------------------------
Technet Mail List provided as a free service by IPC using LISTSERV 1.8e
To unsubscribe, send a message to [log in to unmask] with following text in
the BODY (NOT the subject field): SIGNOFF Technet
To temporarily halt or (re-start) delivery of Technet send e-mail to [log in to unmask]: SET Technet NOMAIL or (MAIL)
To receive ONE mailing per day of all the posts: send e-mail to [log in to unmask]: SET Technet Digest
Search the archives of previous posts at: http://listserv.ipc.org/archives
Please visit IPC web site http://www.ipc.org/html/forum.htm for additional
information, or contact Keach Sasamori at [log in to unmask] or 847-509-9700 ext.5315
-----------------------------------------------------