Hi John Yes! The reason that no-clean fluxes pass old SIR tests is because they volatalize at temperatures ~>40DegC but the SIR used to call for 85DegC/85%RH. If they are tested at 40DegC/90%RH as per the new SIR methods, you will probably see a different story. HP found that and reported on it - and many others also, but I am not sure they have published their problems. No clean flux = very low or no solids = higher preheat = more absorbtion into a swollen laminate = possible electro-chemical reliability issues. Lead-free = much higher process temperatures = a bigger problem? Graham Naisbitt On 9 Nov 2008, at 15:32, John Goulet wrote: > Is there any information on products with No-Clean flux being > effected by moisture over a period longer than that tested in SIR > tests with the SIR comb test coupons? Some customers make products > for vehicles and toys that are subject to more humid conditions. The > No-Clean fluxes used always pass SIR which have high resistance > values even after 196 hours. However if the humidity levels rise > and fall but never to the point of drying out the moisture. I > thinking that the humid spring and summer months could be a problem > if not sprayed with a conformal coat. The other situation I'm > testing is when a moisture sensitive part is used. Tests on three of > the boards showed that the moisture sensitive part was dragging the > surface insulation down. When I localized the heating to this part > with a small Leister heat gun, the resistance across the battery > terminals with the battery removed went back to infinity. Usually > the moisture sensitivity is a factor relative to the SMT reflow proc! > ess and > not an issue in operation. Any info on this? PS this batch was the > first ones using Pb-Free solder paste and that means I'll have to > check if the BOM changed to a different RoHs version of this special > moisture sensitive part. > > > -------------- Original message -------------- > From: John Burke <[log in to unmask]> > >> FYI Werner has developed an Accelerated reliability model for >> SAC405/305 >> solder joint creep-fatigue. Details below >> >> >> John Burke >> >> (408) 515 4992 >> >> >> -----Original Message----- >> From: Leadfree [mailto:[log in to unmask]] On Behalf Of Werner >> Engelmaier /* >> Sent: Friday, November 07, 2008 2:15 PM >> To: [log in to unmask] >> Subject: [LF] Accelerated reliability model for SAC405/305 solder >> joint >> creep-fatigue >> >> Hi all, >> Just to let everybody know, I have developed a creep-fatigue model >> for >> SAC405/305 solder joints. It will be published in a presentation at >> the >> IPC/JEDEC >> Conference on Transitioning to Lead-Free: Strategies for >> Implementation on >> December 8 to 10, 2008 in Dallas, TX. >> >> --------------------------------------------------- >> Technet Mail List provided as a service by IPC using LISTSERV 15.0 >> 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 15.0 > 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 15.0 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 -----------------------------------------------------