TECHNET Archives

January 2003

TechNet@IPC.ORG

Options: Use Monospaced Font
Show Text Part by Default
Show All Mail Headers

Message: [<< First] [< Prev] [Next >] [Last >>]
Topic: [<< First] [< Prev] [Next >] [Last >>]
Author: [<< First] [< Prev] [Next >] [Last >>]

Print Reply
Subject:
From:
"Macko, Joe @ IEC" <[log in to unmask]>
Reply To:
TechNet E-Mail Forum.
Date:
Fri, 10 Jan 2003 11:19:52 -0800
Content-Type:
text/plain
Parts/Attachments:
text/plain (34 lines)
Fellow Techheads,

I am continually being challenged about the amount of time & temperature
required to safely remove moisture from multilayered FR4 bare boards so they
can be safely populated and reflowed.  And, the time/temperature required to
remove moisture from a populated board when a BGA needs to be replaced using
a hot air rework station such as an AIR-VAC DRS24.  I realize that baking
out boards at an elevated temperature will degrade solderability with time
as well as age components so ideally boards should not be baked out any
longer than necessary.

Everyone seems to have a slightly different idea of the time vs. temperature
required which generally ranges from 4 to 24 hours at temperatures as low as
85 to 125 C.    85C definitely seems to low to me.  IPC/JDEC J-STD-033A list
bakeout times for components depending on thickness which seems excessive
for a circuit board.   I have not found any IPC guidelines for circuit
boards.

Anyone like to comment on what has worked for them?   Is there an industry
standard out there?   thanks in advanced for the feedback.

joe

---------------------------------------------------
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
-----------------------------------------------------

ATOM RSS1 RSS2