Fellow technetters,

I am back with the same old problem: bow & twist

we are producing a 14 layer  , cap lamination board for one of our customer

the construction is as shown below:

- - - - - - - - - - - - - - - - -  - -
**************************          3 mil core
- - - - - - -  - - - - -  - - - - -  -
^^^^^^^^^^^^^^^^^^^           1080
- - - - - - - - - - - - - - -  - - - -
**************************          28 mil dummy core
- - - -  - - - -  --  - - - - - - - -
^^^^^^^^^^^^^^^^^^^           2116
 - - - - - - - - - - - - - - - - -  - -
**************************          3 mil core
- - - - - - -  - - - - -  - - - - -  -
^^^^^^^^^^^^^^^^^^^           1080
^^^^^^^^^^^^^^^^^^^           2116
- - - - - - - - - - - - - - - - -  - -
**************************          3 mil core
- - - - - - -  - - - - -  - - - - -  -
^^^^^^^^^^^^^^^^^^^           1080
^^^^^^^^^^^^^^^^^^^           2116
- - - - - - - - - - - - - - - - -  - -
**************************          3 mil core
- - - - - - -  - - - - -  - - - - -  -
^^^^^^^^^^^^^^^^^^^           1080
^^^^^^^^^^^^^^^^^^^           2116
- - - - - - - - - - - - - - - - -  - -
**************************          3 mil core
- - - - - - -  - - - - -  - - - - -  -
^^^^^^^^^^^^^^^^^^^           1080
^^^^^^^^^^^^^^^^^^^           2116
- - - - - - - - - - - - - - - - -  - -
**************************          3 mil core
- - - - - - -  - - - - -  - - - - -  -
^^^^^^^^^^^^^^^^^^^           1080
^^^^^^^^^^^^^^^^^^^           2116
- - - - - - - - - - - - - - - - -  - -
**************************          3 mil core
- - - - - - -  - - - - -  - - - - -  -

Obviously, we are getting warpage in boards
the construction is customer given and he is not ready to change this

Are there any solutions to avoid warp in these boars

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