Here is a note I use on our surface mount boards: BOW AND TWIST SHALL NOT EXCEED 0.75% (.0075" PER INCH) IN ACCORDANCE WITH IPC-A-600 FOR SURFACE MOUNTED BOARDS WHEN MEASURED USING IPC-TM-650, METHOD 2.4.22 Regards, Steve Smith Product Engineer Staco Energy Products Co. Web Site: www.stacoenergy.com & www.stacopower.com DISCLAIMER AND/OR CONFIDENTIALITY NOTICE: This message, including any attached materials, is intended solely for the use of the individual or entity to whom it is addressed and may contain information that is privileged, confidential, and exempt from disclosure under applicable law. If the reader of this electronic mail transmission is not the intended recipient, you are hereby notified that any dissemination, distribution, or copying of this communication is strictly prohibited. If you have received this communication in error, please e-mail or call Staco Energy Products Co. at (937) 253-1191. Thank you for your cooperation. -----Original Message----- From: TechNet [mailto:[log in to unmask]] On Behalf Of Tim Mack Sent: Wednesday, May 23, 2007 3:18 PM To: [log in to unmask] Subject: [TN] PCB Flatness Does anybody know how "flatness" is measured as it relates to circuit board fabrication? I was told that the boards I am ordering would have a flatness of less than 0.5%. 0.5% of what? Any help would be appreciated. Thanks, North Dakota State University Center for Nanoscale Science and Engineering Tim Mack www.ndsu.nodak.edu/cnse Research Engineer --------------------------------------------------- Technet Mail List provided as a service by IPC using LISTSERV 15.0 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/contentpage.asp?Pageid=4.3.16 for additional information, or contact Keach Sasamori at [log in to unmask] or 847-615-7100 ext.2815 ----------------------------------------------------- --------------------------------------------------- Technet Mail List provided as a service by IPC using LISTSERV 15.0 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/contentpage.asp?Pageid=4.3.16 for additional information, or contact Keach Sasamori at [log in to unmask] or 847-615-7100 ext.2815 -----------------------------------------------------