There are no other fluxes on the board. The board was not cleaned after first pass (found this out yesterday). However, keep in mind that this is not white residue at all. The areas affected simply show a lighter hue of green. Almost like the solder mask was emulsified, then hardened. Jason Gregory Manufacturing Engineer Innova Electronics (281)653-5593 (281)653-5594 fax (281)212-0844 cell [log in to unmask] -----Original Message----- From: TechNet [mailto:[log in to unmask]]On Behalf Of Mike Fenner Sent: Friday, March 11, 2005 5:39 AM To: [log in to unmask] Subject: Re: [TN] Cleaning residues off of PCB Been out and have trouble untangling the 2 parallel threads, so I gave up. My apologies if I duplicate responses. Are you vapour cleaning after the first print? If the first clean was not complete, cleaning a twice baked reside will be harder and even less complete and could easily show as a white residue. Are there any other fluxes on board, like a wave solder flux? Or hand touch-up flux? This will often show like this. Regards Mike Fenner Indium Corporation T: + 44 1908 580 400 M: + 44 7810 526 317 F: + 44 1908 580 411 E: [log in to unmask] W: www.indium.com Pb-free: www.Pb-Free.com -----Original Message----- From: TechNet [mailto:[log in to unmask]] On Behalf Of Blomberg, Rainer (FL51) Sent: Thursday, March 10, 2005 3:21 PM To: [log in to unmask] Subject: Re: [TN] Cleaning residues off of PCB Jason, I have seen similar results during cleaning process evaluations. In my case, clear residue was residual flux that remains in the small spaces common to fine-pitch parts after the cleaning solvent has evaporated. You might be seeing the Non-volatile Residue. Evaporation is slowest in the small spaces, especially between solder pad and solder mask. In addition, capillary forces will draw and hold liquid there making it slow to evaporate. This was solved by longer cleaning time (to get more flux off) and better rinsing/drying to rinse away the "dirty" flux removing solvent and get rid of the NVR. I am surprised that your vapor degreasing process alone is not adequate to get rid of flux residue. The vapors should penetrate and get to all surfaces. Either the part is in vapor too short a time or you are seeing residue left by the secondary wash/rinse in "contaminated" terpene. We use Kyzen Ionox I3330 at 140 deg. F followed by a clean Isopropyl alcohol spray rinse. Without the clean IPA rinse, our boards would look like yours. Hope this helps, > Rainer G. Blomberg > Staff Production Engineer > Space Systems - Clearwater > Honeywell International, Inc. > * Phone (727) 539-5534 > * Fax (727) 539-4469 > * Email [log in to unmask] -----Original Message----- From: TechNet [mailto:[log in to unmask]] On Behalf Of Jason Gregory Sent: Wednesday, March 09, 2005 6:37 PM To: [log in to unmask] Subject: Re: [TN] Cleaning residues off of PCB Photo posted. Thanks Steve! You can see (barely - sorry bad photo) some halo-ing around the leads. Like I said, no other detection in open areas or two leaded devices just finer pitch, multi-leaded devices. Follow the link http://www.stevezeva.homestead.com/files/residue_closeup.jpg Jason Gregory Manufacturing Engineer Innova Electronics (281)653-5593 (281)653-5594 fax (281)212-0844 cell [log in to unmask] -----Original Message----- From: TechNet [mailto:[log in to unmask]]On Behalf Of David D. Hillman Sent: Wednesday, March 09, 2005 4:05 PM To: [log in to unmask] Subject: Re: [TN] Cleaning residues off of PCB Hi Jason! Can you send a photo to Steve for posting? A visual would help. Dave Hillman Rockwell Collins [log in to unmask] Hello all, We have some boards that I am requiring some advice on cleaning residues. The PCBs were soldered with SN96 (Sn96.5/Ag3.5). The first pass of the boards look great. However, the second pass looked very suspicious. We are seeing residue that looks like dried, puddled flux residue around most of the leads. The areas mostly affected are multi-leaded components and there is no evidence of this residue in open (non-populated) areas of the board. If we take something like a probe or tweezers and move them along the areas of concern, then it flakes off, but not real easily. I am afraid to do this in fear of damaging the laminate (these are expensive boards). We have tried re-fluxing them with aggressive RMA flux and re-reflowing them, but to no avail. I have just tried soaking them, for 15 minutes, in a 50/50 solution of distilled white vinegar and DI water, but again, to no avail. Does anyone have any suggestions as to something else to use that's aggressive, but not damaging to polyimide (or the solder joints)? TIA, Jason Gregory Manufacturing Engineer Innova Electronics (281)653-5593 (281)653-5594 fax (281)212-0844 cell [log in to unmask] --------------------------------------------------- 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 ----------------------------------------------------- ::::::::::::::::::::::::::: This email, its content and any files transmitted with it are intended solely for the addressee(s) and may be legally privileged and/or confidential. 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