John, Steve is right on the money. Best solution for JIT, one piece flow. When the mechanical-test-packing cell is almost out of boards, you just flip the boards half assembled, with no down time for changeover, and start supplying again. Regards, Ioan -----Original Message----- From: TechNet [mailto:[log in to unmask]]On Behalf Of Steve Gregory Sent: Friday, March 02, 2007 2:09 PM To: [log in to unmask] Subject: Re: [TN] Flip-flop panels Hi John, I've built panels that had flip-flopped boards before, (small narrow double-sided SMT boards for a bar code reader pen), and it made things so easy. One stencil, one SMT set-up, to do both sides of the panel on one line. After they come out of the reflow oven from the first side (and they've cooled down of course), you just stick them right back in the screen printer for the other side without so much as missing a beat...pretty cool, eh? -Steve Gregory- -----Original Message----- From: TechNet [mailto:[log in to unmask]] On Behalf Of John Parsons Sent: Friday, March 02, 2007 12:51 PM To: [log in to unmask] Subject: Re: [TN] Flip-flop panels Ioan, Why would you want to design an array like this? John Parsons -----Original Message----- From: TechNet [mailto:[log in to unmask]] On Behalf Of Tempea, Ioan Sent: Friday, March 02, 2007 10:23 AM To: [log in to unmask] Subject: [TN] Flip-flop panels Hi Technos, the flip-flop nickname actually comes from the Technet, I heard it right here some time (years) ago. What I mean is the panels made up by arrays of alternating top-bottom patterns. I know that the layer stackup has to be symmetrical, that the copper weight has to be symmetrical, but what about the controlled impedance boards? Let's say a 12 layer PCB, that calls for: 4.0 mil lines: 56 ohm trace impedance +/- 10% layers 2,4,5,8,9,11 6.5 mil lines: 50 ohm trace impedance +/- 10% layers 4,9,11 8.1 mil lines: 45 ohm trace impedance +/- 10% layers 4,8,9 8.0 mil lines: 56 ohm trace impedance +/- 10% layers 1,12 Is this PCB a good candidate for flip-flopping? And it is just now that I realized it has 12 layers? Any limitations coming from layer count? And even better, I have one other board with microvias and blind/burried vias. Can this be flip-flopped? Thank you, Ioan --------------------------------------------------- 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 ----------------------------------------------------- --------------------------------------------------- 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 -----------------------------------------------------