What color did it turn? We recently ran some ENIG boards and found the silkscreen turned a pinkish purple color. That color darkened with each successive thermal excursion. We have not done a cause and effect, but, we believe since we've only seen it on ENIG boards that it's somehow related to the bare board process and/or rework to plating that we were not informed of. Anyone in the board fab arena have any ideas? -Carrie -----Original Message----- From: TechNet [mailto:[log in to unmask]] On Behalf Of Martin Butcher Sent: Tuesday, April 19, 2005 6:29 PM To: [log in to unmask] Subject: [TN] PCB Silkscreen Discoloration Hi All, I have a question regarding the discoloration of the silk screen ink after reflow. What can cause it other than overheating during reflow? Here is some background to this question. We received a consigned kit, processed it and shipped it about three months ago. Our profile data shows that the PCB did not reach peak temperatures above 216 deg C. We have run this product once prior with a peak temperature of 212 deg C and with no reports of discoloration. Our client has contacted their board shop concerning this and were told by the board shop that the discoloration is due to overheating. Are there other variables that could account for this? Regards, Martin Butcher, Process Engineer. --------------------------------------------------- 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 847-615-7100 ext.2815 ----------------------------------------------------- --------------------------------------------------- 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 847-615-7100 ext.2815 -----------------------------------------------------