I agree that this sounds like a PCB fab problem. In my experience, it could very well be due to the presence of a contaminant on the boards at the moment the mask is applied. This could simply be that the boards were nor sufficiently dry (yes, water can be a contaminant!). I'm shocked at the idea of pumice or any other abrasive as a preparation for solder mask. This is a ***sure*** way of destroying the solderability. I've written at length on this subject in several books. Abrasives and solderable surfaces are incompatible. Brian Suzanne Foulkes wrote: > I know this was up for a discussion a few weeks ago. Can anyone tell me > what the root cause was determined to be? > > I am experiencing solder mask flaking on a group of boards manufactured > by one certain supplier. It is a random occurrence for example 10 out of > the 100 boards we had this occurr. Then a different board we ran 8 out > of 40 were flaking same supplier as previous one. > > Supplier runs samples at his facility and he see's no flaking. We > changed our solder temperature from 500 degrees to 450 degrees at the > suppliers suggestion and flaking still occurs. He then states maybe were > not using enough flux but review shows plenty of flux if anything maybe > were using to much flux from the way the boards look coming out of the > wave and washer. > > Thanks > Sue Foulkes > QA Manager > AESCO Mfg. > > > > --------------------------------------------------- > 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 -----------------------------------------------------