No, no nickel... Our PWB supplier claims that he was able to repeat the problem by "slightly" oxidizing the copper. When they subjected bare copper boards to an oven bake, completely oxidizing the copper, the results of the HASL was non-wet areas. When the bake was reduced, minimal oxidation, he claims that he got the same results as the production PWBs, where the pads were covered with solder, but, when subjected to a tape test, the solder peeled off. Luckily, this problem is only found on one part number (out of six that were ordered), all of which were HASLed on the same day. We are returning all un-built boards and our supplier will strip the solder and re-HASL. My BIG problem now is, how do I screen the built-up assemblies? We built about 40 of these (quite expensive) assemblies and we're assuming that about 20% are suspect. My first action is to do a tape test on the completed assemblies (on un-used pads) to try and weed out some of the problem boards. After that, I really don't know what to do with the assemblies that passed the tape test. Suggestions? Jim Marsico Senior Engineer Production Engineering EDO Electronics Systems Group [log in to unmask] <mailto:[log in to unmask]> 631-595-5879 -----Original Message----- From: [log in to unmask] [SMTP:[log in to unmask]] Sent: Wednesday, July 21, 2004 6:07 AM To: [log in to unmask]; [log in to unmask] Subject: RE: [TN] PWB SOLDERABILITY Never, any chance they might have been nickel plated before HASL? -----Original Message----- From: Marsico, James [mailto:[log in to unmask]] Sent: Tuesday, July 20, 2004 8:29 PM To: [log in to unmask] Subject: [TN] PWB SOLDERABILITY Good Day Technet: Here's an unusual situation. We recently got a lot of PWBs from our supplier who we've been using for years. The solder on the boards (HASL) looks good, thick and shiny. A couple of weeks ago, after SMT assembly with a fairly aggressive water soluble solder paste, we noticed that one of the components (diode) had fallen off and was sitting on the operator's bench. The pads on the board where the component had fallen off showed bare copper, while the solder fillets remained on the component! Thinking that this was an unexplainable one-time occurrence, the component was soldered back on and the board went on its merry way. Well, a couple of days later, boards from the same lot were soldered and we noticed that some of unused pads or test pads were copper only, with no traces of solder. We then took some bare boards, all of which looked good, and ran them trough our reflow and in-line cleaning process (no flux or solder paste). Low and behold, on about 20% of the boards there were copper pads with no solder, and a few pads where the solder was partially peeling off the pads, exposing the copper underneath (with no traces of copper on the pealed solder). After discussions with our supplier, we both came to the conclusion that some of the boards must have been oxidized to such a degree that solder coated the pads but did not achieve a metallurgical bond. I would have thought that such a condition would result in a de-wet or non-wet condition, but, as I said earlier, the boards looked great! Has anyone else ever come across this before? Jim Marsico Senior Engineer Production Engineering EDO Electronics Systems Group [log in to unmask] <mailto:[log in to unmask]> 631-595-5879 --------------------------------------------------- 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 847-509-9700 ext.5315 ----------------------------------------------------- --------------------------------------------------- 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 847-509-9700 ext.5315 -----------------------------------------------------