Hi folks! Ok, I have sat back long enough and need to square up some mis-information - Greg, you and I really need to talk. The JSTD-002/003 committees have taken your 1996 testing and advanced it a tremendous distance. 1) Gauge R&R of the Wetting Balance: The JSTD-002/003 committees ran a series of round robin tests which resulted in the demonstration that the Wetting Balance equipments could meet industry Gauge R&R expectations. The wetting balance test methodology/standard testing procedures were completely revised (based on the Munie, National Physics Laboratory, and NIST investigations). However, additional investigative efforts were needed to be completed before the committee felt that testing efforts to develop acceptance/rejection criteria could be initiated. 2) The JSTD-002/003 solderability test specification's purpose is to test the robustness of a finish for wettability. Tooooo many people attempt to use and/or believe the specifications are designed to mimic production conditions (this is best described as soldering-ability). Although the committees attempts to have the specifications reflect soldering-ability concerns, it is not possible or practical in terms of testing methodology to mimic production. There are so many flux/process combination that the specifications would cease to be of value (the specifications would be huge and contain a multitude of variations). The test parameters contained in the specifications are designed to have some safety margin in terms of demonstrating the solderability of a surface - a test which gives either a false positive or false negative result is not of value to the industry. 3) The JSTD-002/003 committees completed the round robin on revising the solderability test flux just last year. The old "R" flux was not applicable to the newer finishes on the market (eg. OSP or palladium/nickel) and a new, standardized flux with a specific level of activation was qualified. The new flux improved the overall test variability over the results obtained using the "R" flux for a wide variety of finishes the industry was/is using. 4) Those folks who actually believe that the Dip & Look methodology has a respectable Gauge R&R would be in for an extreme shock. The "active wetting" information that George W. described and the solderability test parameter improvements that the committee has implemented have improved the situation for the industry but we still have room for improvement. The committees have voted that no new solderability test methods will be introduced into the specifications without a demonstrated, industry acceptable Gauge R&R value. 5) The JSTD-002/003 committee is actually one of the largest joint committees at IPC - we have EIA, JEDEC, IPC and IEC representation which means we don't move real fast but we get a tremendous industry cross-section input/review which overall makes the drive for one global solderability specification very real activity. 6) The JSTD-003 committee completed a Gauge R&R study on the SERA testing methodology which demonstrated the SERA equipments to be industry acceptable. However, the committee has not undertaken the round robin testing for SERA acceptance/rejection criteria because of other specification priorities. Many companies use SERA methodology for surface characterization very successfully (the IPC-TM-650 method is in progress) 7) And finally, the JSTD-002/003 has been working diligently on test confirmation of a set of solderability test parameters applicable to Pbfree solderability testing - more "news at 11:00" but the specification proposals should be going out for industry ballot shortly. Dave Hillman JSTD-002/003 Committee Chair [log in to unmask] "Munie, Gregory" <[log in to unmask] M> To Sent by: TechNet [log in to unmask] <[log in to unmask]> cc Subject 05/25/2005 08:17 Re: [TN] Wetting balance AM Please respond to TechNet E-Mail Forum <[log in to unmask]> ; Please respond to "Munie, Gregory" <[log in to unmask] M> Luigi You didn't say what flux you were using. I assume it's the flux called out in the spec. My experience at AT&T (and resulting contributions to the IPC wetting balance test) are that if you use ANY flux but water white rosin (WWR) the results you get in production will NOT equal the results of the wetting test. The test will always look better. I and my co-workers published this as a reliability study at the SMI conference in San Jose, CA in 1995. I have heard the arguments that wetting balance is inherently too noisy to provide good repeatable data from site to site if one uses WWR. Yup! A little activation in the flux definitely improves the repeatability: It makes everything good. And when that happens, from an assembly standpoint, you're the loser. I suggest a simpler alternative: use the "dip and look" test with WWR and the wetting balance to control immersion depth and speed. But only accept the parts if the area wetted exceeds the area dipped. Why? Simple! In production you want the solder to wet "up" the part/wet "over" the lead. When you put the part in the solder with WWR and the solder climbs up the lead you know it's good! If all the solder does is wet the immersed area . . . well, on my desk I have some carbon fiber bundles that exhibit good "wetting" per the current test. They're well covered with SnPb over the area immersed. But I defy anyone to actually make good connections in production with leads like that. (Years ago John Devore, if I remember correctly, would show people a solder surface that was well wetted. Then he'd hand it to them. It was a wood toothpick with solder adhered to part of the wood. Sure looked it'd solder per the spec!) So, per my opinion, WWR and demonstrated active wetting of the parts are the only way to go in solderability testing. Greg Munie -----Original Message----- From: Luigi Cantagallo [mailto:[log in to unmask]] Sent: Wednesday, May 25, 2005 2:00 AM To: [log in to unmask] Subject: [TN] Wetting balance Hello Technetters, I have questions about wetting balance. We intend to use a wetting balance not to accept/reject supplied SMD's (Our SMD's are 1 to 5 years old) but to minimize the risk of solderability defects in production (Low volume, SnPb technology). So we don't apply J-STD-002D criterium but we try to find them to corroborate wetting balance and production results. On some tests (Wetting balance calibrated and in order, same type of flux, same alloy) on same component lots, we have not a perfect correspondence between wetting balance and visual inspections results in production (Vapor phase soldering). One of the case is "Good at the solderability test/Defect in production" and this one is the most risky. Somebody have experience with that kind of problem? What actions have you made ? Thanks for answers. Best regards, CANTAGALLO Luigi --------------------------------------------------- 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 847-615-7100 ext.2815 ----------------------------------------------------- --------------------------------------------------- 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 847-615-7100 ext.2815 ----------------------------------------------------- --------------------------------------------------- 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 847-615-7100 ext.2815 -----------------------------------------------------