Although this board wasn't conformal coated, this "FOD" was found in the soldermask when I was working at a past employer: http://stevezeva.homestead.com/StrangeMaskDefect.jpg I wonder would you need to put this in a SEM to figure out if it is a tin whisker or not? Steve -----Original Message----- From: TechNet [mailto:[log in to unmask]] On Behalf Of Dennis Fritz Sent: Thursday, May 19, 2011 3:47 PM To: [log in to unmask] Subject: Re: [TN] Conformal Coating and FOD Not exactly the same, but.... When our interns are looking for tin whiskers, they put the part in the Scanning Electron Microscope. If the FOD is dark - it is non-metallic and not a tin whisker. If it is "white", it is metallic and most likely a whisker. We have found very little metallic debris on commercial boards that is not tin whiskers. I know, I know, zinc whiskers can come off the computer room floor gratings and deposit on electronics. We haven't found any of those yet. But some folks sure keep their personal computers in some dusty, dirty locations. TALK ABOUT DUST BUNNIES. Denny Fritz -----Original Message----- From: Douglas Pauls <[log in to unmask]> To: TechNet <[log in to unmask]> Sent: Thu, May 19, 2011 3:03 pm Subject: [TN] Conformal Coating and FOD Good afternoon all, I have an interesting question to pose to the forum. An internal debate resently rages internally, so I thought I would turn to cool rational eople (sit down Dewey). When inspecting conformal coating, one of the things that "may" be onsidered a defect is the presence of Foreign Objects and Debris (FOD), hich "might" require disposition. 1. Is there any guidelines you all use to differentiate FOD in coating hat requires action (e.g. FOD as a defect), vs. FOD that does not cosmetic only)? . If you differentiate bad FOD from doesn't-matter FOD, what criteria do ou use? In essence, how much FOD is FOD. Thanks. Doug Pauls ______________________________________________________________________ his email has been scanned by the MessageLabs Email Security System. or more information please contact helpdesk at x2960 or [log in to unmask] _____________________________________________________________________ --------------------------------------------------- echnet Mail List provided as a service by IPC using LISTSERV 16.0 o unsubscribe, send a message to [log in to unmask] with following text in he BODY (NOT the subject field): SIGNOFF Technet o temporarily halt or (re-start) delivery of Technet send e-mail to [log in to unmask]: SET Technet NOMAIL or (MAIL) o receive ONE mailing per day of all the posts: send e-mail to [log in to unmask]: SET Technet Digest earch the archives of previous posts at: http://listserv.ipc.org/archives or additional information, or contact Keach Sasamori at [log in to unmask] or 47-615-7100 ext.2815 ---------------------------------------------------- ______________________________________________________________________ This email has been scanned by the MessageLabs Email Security System. For more information please contact helpdesk at x2960 or [log in to unmask] ______________________________________________________________________ --------------------------------------------------- Technet Mail List provided as a service by IPC using LISTSERV 16.0 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 For additional information, or contact Keach Sasamori at [log in to unmask] or 847-615-7100 ext.2815 ----------------------------------------------------- ______________________________________________________________________ This email has been scanned by the MessageLabs Email Security System. For more information please contact helpdesk at x2960 or [log in to unmask] ______________________________________________________________________ --------------------------------------------------- Technet Mail List provided as a service by IPC using LISTSERV 16.0 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 For additional information, or contact Keach Sasamori at [log in to unmask] or 847-615-7100 ext.2815 -----------------------------------------------------