Folks, Is there a method of determining the maximum permissible size of two board types? a) A SMT PCB containing Fine pitch QFP devices b) A SMT PCB containing PBGA 388pin 1.27mm pitch & Fine pitch QFPs with respect to Bow and Twist. I am interested in how the thickness of the board relates to maximum bow and twist. I'd like to determine this before I design the layout, rather than find out it is wrong after performing the tests of IPC-6012A, IPC-TM-650 2.4.22. Regards, Colin Weber --------------------------------------------------------------------------------- Technet Mail List provided as a free service by IPC using LISTSERV 1.8d 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 delivery of Technet send the following message: SET Technet NOMAIL Search previous postings at: www.ipc.org > On-Line Resources & Databases > E-mail 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 ---------------------------------------------------------------------------------