I can think of plenty of reasons not to touch up these parts, most of which you have already mentioned but the main reason is the risk of cracking the caps. Cracked caps can fail months after they have been in service and if you allow touch up operators to rework every capacitor sooner or later you will see cracked components. You must convince your customer of the error of their ways, it is you they will blame when it all goes wrong... Have you tried showing them IPC610, most companies are impressed by the quality of it and end up adopting it as their standard!?!? Neil _____________________________ Neil Atkinson Electronics Quality Manager UK-NSI Co. Ltd. Merse Road, North Moons Moat, Redditch, Worcs. B98 9HL, U.K. Tel: +44 (0) 1527 585055 Fax: +44 (0) 1527 585025 e-mail: [log in to unmask] _____________________________ -----Original Message----- From: Jim Smith [mailto:[log in to unmask]] Sent: 13 August 2002 04:01 Subject: Re: Solder fillet requirement Peter: I suspect you've just encountered a classic example of requirements mindlessly transferred when product technologies change. As all us old-timers remember, back in the days of single-sided through-hole boards there was debate about the maximum allowable gap in the solder where it crossed the (non-plated) hole. (Exactly why the gap should be a concern was never clear to me inasmuch as the bottleneck for electrical flow has always been the traces. Moreover, the "problem" was easily resolved by reducing the hole diameter relative lead size. But I digress.) The generally established requirement was 75% coverage (though some companies settled on 50% or so), one of many ill-conceived decisions that ensured job security for touchup operators. When double-sided and ultimately multi-layer through-hole assemblies arrived, the same debate took place with respect to minimum permissible solder flow up plated through-holes. The requirement was basically derived from the single-sided requirement. That is, 75% fill (or, in some companies, 50% or so). Of course, the traces continue to be the electrical bottleneck regardless of the amount of solder (unless the flow is prevented by breaks in hole plating, in which case it doesn't matter where the flow is halted). Now we get to surface mount assemblies and -- surprise -- you've got a customer who wants to see 75% solder flow up the end caps. That kind of thinking has been inevitable and I imagine it's more widespread than any of us realizes. Oh yes, I almost forgot: touchup operators still have job security. Best wishes, Jim Smith Managing Director Cambridge Management Sciences, Inc. 4285 45th St. S. St. Petersburg, FL 33711-4431 Tel: (727)866-6502 ext. 21 Fax: (727)867-7890 eMail: [log in to unmask] Peter Lee wrote: > Technet, > > One of our customers is requesting 75% solder fillet height on all the > SMT Porcelain capacitors (0805 package size with taller profile) used > for a RF application. We told them based on our experience that the > excess paste volume (and wetting) can not be achieved by our SMT stencil > process. IPC only requires 25% for class 2 products. But they are now > specifying hand soldering these components. > > Can anyone see any reason for doing this? I am prepared to go back to > our customer to convince them otherwise (reasons such as extra labour, > process inefficiency, solder joint reliability etc.) > > Rgds, > Peter > > ---------------------------------------------------------------------------- ----- > 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 has been scanned for all viruses by Star Internet. 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