We have several customers doing this and similar. For smaller boards these are most often treated as if a BGA. Other methods include - to process side by side using a flex ribbon or wires and fold the board on top after. - using pins [through hole in at least one board to give location. The through pins are either wave soldered, or reflowed with washer/rectangle preforms to give reinforcement to the paste. The preforms are ribbon or magazine packed so they can be P&P to paste like a regular component. Some are hybridised so a couple of pins are used as location for the "bga" board, I suppose it all depends on your approach to the problem - what ever floats your boat as they say! Regards Mike Fenner Indium Corporation T: + 44 1908 580 400 M: + 44 7810 526 317 F: + 44 1908 580 411 E: [log in to unmask] W: www.indium.com Pb-free: www.Pb-Free.com -----Original Message----- From: TechNet [mailto:[log in to unmask]] On Behalf Of Phil Nutting Sent: Friday, October 01, 2004 2:24 PM To: [log in to unmask] Subject: [TN] stacking PC boards and reflowing together Good morning, Has anyone tried reflow soldering one circuit board on top of another as if the top board were just another SMT part? We have a design where we currently design this as thru-hole boards and attempt to solder them together... sometimes three boards high, which never works to my satisfaction. Phil Nutting Manufacturing Engineer Kaiser Systems, Inc. 126 Sohier Road Beverly, MA 01915 voice 978-922-9300, ext. 2315 fax 978-977-3018 e-mail [log in to unmask] www.kaisersystems.com --------------------------------------------------- Technet Mail List provided as a 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/contentpage.asp?Pageid=4.3.16 for additional information, or contact Keach Sasamori at [log in to unmask] or 847-509-9700 ext.5315 ----------------------------------------------------- ::::::::::::::::::::::::::: This email, its content and any files transmitted with it are intended solely for the addressee(s) and may be legally privileged and/or confidential. If you are not the intended recipient please delete and contact the sender by return and delete the material from any computer. Any review, retransmission, dissemination or other use of, or taking of any action in reliance upon, this information by persons or entities other than the intended recipient is prohibited. Messages sent via this medium may be subject to delays, non-delivery and unauthorized alteration. This email has been prepared using information believed by the author to be reliable and accurate, but Indium Corporation makes no warranty as to accuracy or completeness. In particular, Indium Corporation does not accept responsibility for changes made to this email after it was sent. Any opinions or recommendations expressed herein are solely those of the author. They may be subject to change without notice. ::::::::::::::::::::::::::: --------------------------------------------------- Technet Mail List provided as a 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/contentpage.asp?Pageid=4.3.16 for additional information, or contact Keach Sasamori at [log in to unmask] or 847-509-9700 ext.5315 -----------------------------------------------------