Steve, For redesign considerations: What I had to do once in a similar case (except my board was oval in shape) was in each tab location board profile would indent .005, then the route tab was created as normal. So in your case there would be 4 locations where the profile would not be a true circular board. I know more router time and programing, but then no deburring and no need to file. This is of course you can move conductors or components away from edge of board, (.005 worth). But if this was incorporated into the PWB design like we did then it works well. The Tab of course takes up more room because of indent, but we used a very small dia. router bit ( I think it was .035 or so) to create indent, where main router bit was .090 dia. I guess this still leaves you manually breaking boards out of panel. good luck, Greg Scott Snr PCB Designer Cray Inc. Steve Gregory wrote: > Hi all, > > We just got an assembly in here that is a little over 1.50" in > diameter. It comes in a 8-up panel, with each board having four tabs > holding it into the panel. > > We built 3 panels on a quick turn for our customer, and after we built > them, the "mouse-bites" they had on the tabs didn't lend themselves to > being broken easily, and I felt it was taking too much force to > singulate the boards...I didn't want to fracture any solder joints or > parts. So I got my trusty Dremel out and singulated them (it was only > 24-boards). > > One peculiarity about this little board, is that the circumference on > the top, bottom, and edge is plated, and the plating must stay intact, > except where the tabs were. > After the boards are built, they are conformal coated except for the > plated area around the circumference. > > The dimensional tolerance for the diameter is 1.650" +/- .005". So if > there is any proud material left at the tab area after the board is > singulated, you can imagine what a PIA it is to have to file this down > to meet spec...go to: > > http://www.stevezeva.homestead.com > > and look at "Round Assembly" to get a better idea of what I'm dealing > with. > > My question is, what sort of tab configuration would you recommend > that would be able to stay within that +/- .005" dimension and not > have to file things down? Is it possible? This is a double sided SMT > assembly using a .062" thick board. > > Thanks in advance! > > -Steve Gregory- > --------------------------------------------------------------------------------- > 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 > --------------------------------------------------------------------------------- --------------------------------------------------------------------------------- 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 ---------------------------------------------------------------------------------