Following short note prepared by Jim Moffitt and posted by the EMPF HelpLine: Regarding your status as an industry orphan... It is true that certain component types (transformers, chokes, inductors, trimpots, variable capacitors, speakers, microphones, baro-transducers, optical encoders, etc., etc.) have been purposely excluded from conventional solderability test described by ANSI/J-STD-002. The exclusion(s) are because most of the components mentioned will fail catastrophically when subjected to the steam aging tests of ANSI/J-STD-002, and requiring that assets be sacrificed to a destructive test does not make good sense. My suggestion to you would be to effect some "process development" followed by strict "process controls" to assure that connections external to your product are indeed solderable. - First step would be to define a process to assure that a solderable coating is present on external elements. Confirm by test (test of ONLY the solderable lugs or surfaces that is) that the solderable coating achieved will comply with the solderability requirements for Category 3 of ANSI/J-STD-002. That is, demonstrate acceptable solderability after 8-hrs.(+/-15 min.) of steam aging. The test is intended for surfaces finished with Sn or Sn/Pb coatings which will be soldered after an extended storage (e.g. greater than 4 months) from the time of testing and/or which see multiple thermal exposures prior to soldering. - Second, freeze your process to assure repeatable results and provide your customers a Certificate of Compliance to assure them that the solderable interconnects of your product meet the requirements of ANSI/J-STD-002 for Category 3 applications. - Now, regarding the subject of solder connections internal to components you build. Most machine solder systems (whether reflow or wave) will control the reflow temperature or solder bath temperature fairly closely (ANSI/J-STD-001 advocates a bath temperature in the range of 230 to 290 deg. C which is controlled within +/- 5 C deg. of the set point). The requirement of J/STD-001 that solders be in accordance with J/STD-006 leaves you plenty of options internally. Note that the advocacy of Sn60, Pb36, and Sn63 (par. 4.1 of J/STD-001) are recommendations intended to apply to solder connections external to a component; that is surfaces to which your customer must make solder connection or solder connections which may be subject to rework or repair by the user (purchaser of the finished product). If I were you I would look in J/STD-002 and select a solder other than Sn63/Pb37 for completing connections internal to the components you manufacture. For instance, Sn10/Pb90 has a liquid/plastic range of 275 to 302 deg. C; Sn05/Pb95 has a range of 308 to 312 deg. C (narrower plastic range), as does Sn05/Pb94/Ag01 which has a range of 296 to 301. Any of the above should be usable to solder connections internal to components, and may be expected to satisfactorily survive exposure to a manufacturing process which is operated in accordance with best industry practice and is in control. - I hope the above helps. If you want/need additional definintion regarding the intent of the J/STDS please contact David Bergman at the IPC. If additional discussion is appropriate I can be reached at the EMPF, 317/655-3673 Ext. 121, or by return e-mail. Regards, Jim Moffitt/EMPF> ********* >We're pretty much one of the 'orphans' of the soldering specs. >MIL-STD-2000A specifically states that it doesn't apply to inductive >devices. Most of the other specs pretty much ignore transformers, >inductors, and similar stuff. We have to solder internal connections that >may, or may not, reflow during wave soldering. Our leads have to meet >'solderability.' > >Yet, our Customers (We always capitalize that word.) want us to solder to >IPC requirements. How? > Do we just 'cherry pick' what seems applicable? > Should there be a separate section in the spec for inductive devices? > Should there be a separate spec for inductive devices? > >How do manufacturers of other components not mentioned in the soldering >specs solve this problem. > >We'd love to have a bit of feedback on the subject. > >Mike Middleton, engineer >Wirebenders Inc. >Custom Transformers and Inductors >voice (602) 861-1856 fax (602) 870-9242 >e-mail [log in to unmask] ***ALL NEW EMPF PHONE NUMBERS*** Jack Crawford, HelpLine Coordinator Electronics Mfg. Productivity Facility ****NEW--317.655.3688 ****FAX 317-655-3699 714 N Senate Ave, Suite 100 Indianapolis IN 46202-3112 VISIT OUR HOME PAGE AT: http://www.empf.org [log in to unmask] *************************************************************************** * TechNet mail list is provided as a service by IPC using SmartList v3.05 * *************************************************************************** * To unsubscribe from this list at any time, send a message to: * * [log in to unmask] with <subject: unsubscribe> and no text. * *************************************************************************** * If you are having a problem with the IPC TechNet forum please contact * * Dmitriy Sklyar at 847-509-9700 ext. 311 or email at [log in to unmask] * ***************************************************************************