We had this happen a while back and it was posted here on the net. We were real concerned and stopped production to find out what happened. It was caused by the flux attacking the surface of the solder mask and it only showed up after wave solder. We had the boards sent to an outside inspection service and the report came back saying it was only a 'surface etch' (much like a fine sand blast on glass) and had no effect on the solder mask other than cosmetic. I can send you the inspection report if you need it. Tom Parkinson - Quality System Manager - CIT WinTronics, Inc. Ph: 724-981-5770 Ext. 235 Fax: 724-981-1772 -----Original Message----- From: TechNet [mailto:[log in to unmask]] On Behalf Of Morse, Carrie Sent: Thursday, April 22, 2004 2:28 PM To: [log in to unmask] Subject: Re: [TN] White Discoloration -- Excessive Heat, Insufficiently Cured SM, or, Both? Here's the status. I baked the boards for 45min @ 250F and...I still have the white haze. No change. So, What do you all think? (IOW--HELP!!!!) -Carrie -----Original Message----- From: Brian Ellis [mailto:[log in to unmask]] Sent: Thursday, April 22, 2004 2:06 AM To: TechNet E-Mail Forum.; Morse, Carrie Subject: Re: [TN] White Discoloration -- Excessive Heat, Insufficiently Cured SM, or, Both? I'm not saying that this is the cause, but another possibility is hydrolysis of the uncured solder mask. If the boards are coated and then stored in a humid atmosphere before development (either before or after exposure) for more than an hour or two, then some components in the chemistry may absorb sufficient humidity to hydrolyse, partially upsetting the polymerisation. I suggest methylene chloride would be better than acetone for a wipe test, but it depends on the chemistry of the LPI. Brian Morse, Carrie wrote: > We are wave soldering a LPI board and seeing a Whitish Discoloration > -- Haze like -- only in the areas that the board has seen OA flux and wave. > We are using a wave pallet and the areas not exposed do not exhibit > this phenomena. This board is also processed through SMT for one side > and we do not see this around any of the SMT. > > We have not seen this problem in the past, and, the Wave operator > states that the wave recipe has not changed. > > So, I am wondering -- if LPI is not fully cured, will it turn white > when exposed to OA flux and Wave? > Also, what IS the max temp LPI should be able to see and for how long > without discoloring? > We've done an Acetone test, but, it comes up clean and....I think I > read in a previous posting that the Acetone may not be an effective > test for LPI. Is that true? If so, What IS an effective test? > > I'm headed to the Omega tester to see "how clean" the board is. > > All advice is welcome! > > -Carrie > > > > --------------------------------------------------- > 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 ----------------------------------------------------- --------------------------------------------------- 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 -----------------------------------------------------