Ted I imagine your interest in the thickness of OSPs is associated with their ability to withstand thermal stresses and still provide a solderable surface. I am unaware of any definitive studies that showed a strong correlation between OSP solderability and thickness. Consequently, it appears that the two are unrelated which initially is contrary to perception. Probably a better index is the strength of the chemical bond between the OSP and the base metal (copper). At the same time, the thicker the coating the more likely it will be applied after electrical test; it is difficult to penetrate thick OSP coatings. This is undesirable since most OSP processes involve a micro etch immediately before applying the OSP that removes copper in the barrels of the board. Best regards Lee -----Original Message----- From: TechNet [mailto:[log in to unmask]] On Behalf Of Ted Kong Sent: Thursday, November 11, 2004 8:14 PM To: [log in to unmask] Subject: [TN] OSP standard Hi fellow Technettes, Is there a standard on OSP thickness and tolerances? If anyone is using OSP, please let me know what thickness and tolerance are being specified. Thanks all in advance. Ted Kong __________________________________________________ Do You Yahoo!? Tired of spam? Yahoo! Mail has the best spam protection around http://mail.yahoo.com --------------------------------------------------- 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 -----------------------------------------------------