Thanks Ian, Would you expect black mask to leave a copper colored residue? If you look closely at the picture, you can see the inner layer copper clearance from the NPH, and then the "residue" appears to be the same exact coloration. Kevin Glidden Manufacturing Engineer Luminescent Systems Inc. -----Original Message----- From: Ian Hanna [mailto:[log in to unmask]] Sent: Friday, September 28, 2007 10:50 AM To: TechNet E-Mail Forum; Kevin Glidden Subject: RE: [TN] Copper Staining in PCB laminate Hello Kevin Lets re-define 'inside'. If its mask pigment It could easily be trapped in the pours of the laminate on the outside surface and not easily cleaned off. Does it appear to be on (or very close to) the outer surface, or does it appear deeper in the material? I find depth-of-field on a microscope a useful aid in establishing relative depth of features... If it's only a discolouration on (or close to) the surface of the laminate I would use the boards and lightly grill the supplier. If it appears on the copper or silkscreens or seems deeper inside I would demand a much more comprehensive analysis prior to use. Again, my first suspect would be the black soldermask -- this stuff can be brutal to fabricators (and I'm a fabricator that uses black mask with regularity) Ian -----Original Message----- From: TechNet [mailto:[log in to unmask]] On Behalf Of Kevin Glidden Sent: Friday, September 28, 2007 10:19 AM To: [log in to unmask] Subject: Re: [TN] Copper Staining in PCB laminate It appears to be inside - it doesn't clean off. Kevin Glidden Manufacturing Engineer Luminescent Systems Inc. 4 Lucent Drive Lebanon, NH 03766 (603) 643-7766 x3152 -----Original Message----- From: Ian Hanna [mailto:[log in to unmask]] Sent: Friday, September 28, 2007 10:07 AM To: TechNet E-Mail Forum; Kevin Glidden Subject: RE: [TN] Copper Staining in PCB laminate IS this staining on the surface of the laminate or does it appear to be inside. Is there any indication of residue on the copper surface. My first guess would be pigment from the black solder-mask, but that's just a first guess...Ian -----Original Message----- From: TechNet [mailto:[log in to unmask]] On Behalf Of Kevin Glidden Sent: Friday, September 28, 2007 9:06 AM To: [log in to unmask] Subject: [TN] Copper Staining in PCB laminate We recently received a shipment of PCBs where the exposed outer layer laminate has staining that looks like copper. I have a photo - <http://tinyurl.com/yp9za2> http://tinyurl.com/yp9za2 My question is what would cause this? I've never seen it before, but I am thinking something in the Copper plating process. The vendor is telling us it is staining but it is an asthetic issue only. What would cause it? Is it an asthetic issue only? It seems to me if the staining was caused by some plating chemistry, then it would effect the laminate properties, particularly the insulation resistance. Thanks! Kevin Glidden Manufacturing Engineer Luminescent Systems Inc. --------------------------------------------------- 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 -----------------------------------------------------