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