Madhu,
Speak to your pre-preg supplier, but 2.5 deg/min is slower than I'm used to.
A more usual rise would be 6 to 8 degC/min when the resin is molten, usually
between 60 and 140 degC.
Resin recession may point to the resin being undercured especially if you
only saw it after removing the post cure. Assuming you're bonding FR4 you
need at least 30 minutes at 180 degC to cure (depending on the resin
system).

hope this helps

Geoff Layhe
Lamar UK

-----Original Message-----
From: [log in to unmask]
[mailto:[log in to unmask]]
Sent: 25 March 2003 09:44
To: [log in to unmask]
Subject: [TN] Laminate voids & resin recession


hello techies,

Lately we are observing laminate voids & resin recession in some of our
boards
the problem has not become severe but it is in the increasing trend

well , to give some info
We have oil heated vacuum assisted presses
our heat rise rate is 2.5 deg per min
we are using kiss pressure of 50 psi for 10 mins before going into full
pressure
we are observing the problems in all the constructions irrespective of
style of prepreg

the only change what we have made is removal of the post baking what we
were doing after re-lamination? will it make any impact
i went through the archives but couldn't find any satisfactory answer

any suggestions?remedies?links?references?.......

cheers,
Madhu






**********************************************************************
This email and any files transmitted with it are confidential and
intended solely for the use of the individual or entity to whom they
are addressed. If you have received this email in error please notify
the mail system admin at AT&S India Limited [log in to unmask]

This footnote also confirms that this email message has been swept by
MIMEsweeper for the presence of computer viruses.

www.mimesweeper.com
**********************************************************************

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


Private & Confidential:
This e-mail message is confidential and is intended solely for the person or
organisation to whom it is addressed.  If the message is received by anyone
other than the addressee please return the message to the sender by replying
to it and then delete the message from your computer.

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