Eccobond 45 is a good adhesive for component bonding when used in harsh environments. Peter "D.Terstegge" <[log in to unmask]> 13/07/2002 05:35 AM Sent by: TechNet <[log in to unmask]> Please respond to "TechNet E-Mail Forum."; Please respond to "D.Terstegge" To: [log in to unmask] cc: (bcc: DUNCAN Peter/Asst Prin Engr/ST Aero/ST Group) Subject: Re: [TN] part/pad mismatch Hi Graham, It'll probably be impossible to make this thing look like IPC3, and the next best thing to worry about is the actual strength of the bonding from the QFP to the board. I thought that perhaps you can achieve the extra needed adhesion by using some kind of glue underneath the part (or embedding it completely). Don't know what kind of adhesive would be best for the job, but thought I'd propose this alternative kind of solution to your problem..... Daan Terstegge http://www.smtinfo.net ----- Original Message ----- From: Graham Collins To: [log in to unmask] Sent: Friday, July 12, 2002 8:46 PM Subject: Re: [TN] part/pad mismatch Hi Steve Interesting company! That said, I don't think I could sell this one to my customer - this is a class 3 high rel vehicle electronics beast, and will be seeing some serious off-road action. Their mods might stand up to that, but proving it to my satisfaction would be tough, and my customer would be more skeptical than I am... I've also talked with Circuit Tech corp about replacing the pads, theoretically possible but again a tough sell to the customer. If I'm "lucky" this won't be a timing sensitive part, and we will end up dead-bugging and wiring the thing. Ah well, it's only a 72 lead part... Thanks! - Graham regards Graham Collins Process Engineer, Northrop Grumman Atlantic Facility of Litton Systems Canada (902) 873-2000 ext 6215 >>> [log in to unmask] 07/12/02 02:52PM >>> Hi Graham! You're probably gonna have a heck of a time finding some sort of adaptor that will work, but I have another suggestion. Have you ever heard of Additive Services? Go to: http://www.additive.com/ They're a company that has a process to make wireless ECO's, meaning that they can add conductors to printed circuit boards to make design changes and you don't have to add jumper wires. I called them and explained your issue. Basically you need some longer pads so you can get a heel fillet on the device when soldered to the PCB. They told me that it would be no problem. However, they can only work with bare boards. He asked me what the quantity would be, and I told him I didn't know. I talked with a gentleman named Darren Cossette at (603) 889-1999, and told him I would give you the information... If this sounds like something that would work, give him a call... Hope this helps ;^) -Steve Gregory- > Good day Technet! It's Friday and of that I am glad. > > I have a new design where a part (a quad flatpack, 50 thou pitch part) does > not match the pads on the board. As-is, I can attach it but there will be > no heel fillet as the heel overhangs the end of pad by a fair bit. > > I have examined and discarded the three obvious options: > - re-form the part to fit: not a good option due to the fact that I'd have > to straighten and then bend the leads in the opposite direction. > - buy un-formed parts and form to fit - can do, but schedule will be > totally in the dustbin. > - re-spin the board to fix the pad layout - again the schedule will be > totally out the window. > > So - that leaves me looking for an adaptor. Can Technetter's advise me of > anyone making such beasts on a quick turn basis? > > As always, thanks. And a good weekend wish to all. > > regards > > Graham Collins > Process Engineer, > Northrop Grumman > Atlantic Facility of Litton Systems Canada > (902) 873-2000 ext 6215 > --------------------------------------------------------------------------------- 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 --------------------------------------------------------------------------------- [This e-mail is confidential and may also be privileged. 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