Thanks George for your feedback, The "black pad" diagnostic has been established by our EMS provider and "acknowledged" by myself. The plating spec used was 3-8 u" immersion gold over 100-200 u". That is the first time I face such a problem... Do you believe that pcb manufacturer has the inspection and qualification equipement to make sure everything's fine with ENIG plating ?? Is there any pcb supplier on the line willing to answer ? Unfortunately, even if some papers has been published up to now about the subject it seems it's still unclear about what is the real cause of the problem. So I agree with you about the need of a thorough scientific investigation about that. Also agree that ENIG must very reliable versatile finish... Regards, Mario -----Original Message----- From: George Milad [mailto:[log in to unmask]] Sent: 22 novembre, 2002 11:59 To: [log in to unmask] Subject: Re: [TN] Black pads suspected on ENIG pcbs: how to screen assembled pcbas ? Bonjour Mario, This is a loaded question. I am not sure that there is a staright answer to it. However it would be important to find out how "Black Pad" has been established as the cause of the defect. The term "Balck Pad" althu initailly a very specific one, is now widely attributed to any soldering or joint reliabilty issues with the ENIG finish. This wide indiscriminate use, interferes with a thorough scientific investigation that may expose other important root causes. How much gold was specified? The new IPC-4452 ENIG specifications specifies 3 - 5 uins 0.075 to 0.125 microns. It also warns that excessive gold thickness could lead to problems with the surface of the underlying Nickel. if properly specified and reasonably controlled during manufacturing is a very reliable versatile finish. George Milad Chairman IPC Plating Committee UIC Tech Sales Rep (516) 901-3874 cell --------------------------------------------------- Technet Mail List provided as a free 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/html/forum.htm for additional information, or contact Keach Sasamori at [log in to unmask] or 847-509-9700 ext.5315 ----------------------------------------------------- --------------------------------------------------- Technet Mail List provided as a free 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/html/forum.htm for additional information, or contact Keach Sasamori at [log in to unmask] or 847-509-9700 ext.5315 -----------------------------------------------------