Your proposed requirement is equivalent to the current IPC 6012 spec (0.75%) for boards 6"x6"or smaller. What would be your maximum board size? If 18"x24", .065 would be equivalent to 0.27% for bow and 0.21% for twist. I have a panel that size at my desk but no pin gages to measure the deflection. I also have a micrometer and paperclip that is 0.035" thick and it won't fit under the board anywhere so this board would meet your spec. A good design with balanced construction can probably be built to your spec, but you can expect a lot of questions and even resistance when people see your requirement. If your designs are unbalanced, it can be difficult to meet the IPC standard much less something more stringent. > ---------- > From: Richard Hamilton[SMTP:[log in to unmask]] > Reply To: TechNet E-Mail Forum.;[log in to unmask] > Sent: Wednesday, April 21, 1999 12:03 PM > To: [log in to unmask] > Subject: [TN] Bow and Twist > > Hello TechNetters, > > I really hate to beat an almost dead horse to death, but........ > > I would like opinions on a requirement for Bow (Warp) and Twist that > calls > for .065" maximum on any size board. Is this unreasonable? Can it be > done? > Does it require more than normal handling? Does it require excessive > extra > handling? > > As usual, Thanks in advance for your assistance! > > Richard Hamilton > Clemar Mfg. / Rain Bird > [log in to unmask] > > ################################################################ TechNet E-Mail Forum provided as a free service by IPC using LISTSERV 1.8c ################################################################ To subscribe/unsubscribe, send a message to [log in to unmask] with following text in the body: To subscribe: SUBSCRIBE TechNet <your full name> To unsubscribe: SIGNOFF TechNet ################################################################ Please visit IPC's web site (http://www.ipc.org) "On-Line Services" section for additional information. For technical support contact Hugo Scaramuzza at [log in to unmask] or 847-509-9700 ext.312 ################################################################