> -----Original Message----- > From: Dehoyos, Ramon > Sent: Monday, August 18, 2003 12:41 PM > To: [log in to unmask] > Subject: RE: [TN] placement verification of uBGA > > > > > > > > Hal: > Do you know the component's body tolerances? > Regards, > Ramon > > > -----Original Message----- > From: Hal Winslow [SMTP:[log in to unmask]] > Sent: Monday, August 18, 2003 10:22 AM > To: [log in to unmask] > Subject: Re: [TN] placement verification of uBGA > > Steve (and others...), > I would caution you about using a silkscreen pattern to align > components. Keep in mind that the silkscreen operation is only loosely > aligned (probably +/- .005") to the circuitry patterns on the board, which > is what you want your components aligned to. This might be too much of a > tolerance, especially if it is truly a uBGA you are placing. > > Putting down the "chevrons" you mention would be the correct method, > since they are perfectly aligned to the pads that your component is being > placed on, since they are created during the same etching process. > > Hal > > -----Original Message----- > From: TechNet [mailto:[log in to unmask]]On Behalf Of > Steve Gregory > Sent: Friday, August 15, 2003 5:56 PM > To: [log in to unmask] > Subject: Re: [TN] placement verification of uBGA > > > Hi Larry! > > Something I've seen done before, is to either have a > silkscreened outline of the part put on the board, or more recently with a > board we built here, have "placement cheverons" etched into the board at > the 4-corners of the device. Go to: > > http://www.stevezeva.homestead.com > > and look at "Placement Chevrons". Of course these have to > match the outline of the body of the part, but the operators can easily > tell visually, if the part is placed accurately or not....pretty slick if > you ask me. But you do have a battle getting the designers to incorporate > something like that. > > -Steve Gregory- > > > > > > I'm wondering what you all use for placement > verification of uBGA? Before running a new setup, we take a solder sample > PCB and put double sided tape on it. Place the components on the PCB, when > its finished the machine operator hauls the PCB over to the techs for them > to Ersa and xray it to verify placement accuracy of the uBGA. I'm looking > for something which would allow the machine operator to verify the > placement themselves. Purchasing additional Ersa and xray equipment > wouldn't be an option. Any suggestions? > > Larry > > > > > > -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 > ----------------------------------------------------- > --------------------------------------------------- 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 -----------------------------------------------------