Werner, You state the value of 0.8mil Cu knee thickness for LF solder PTHs. What is the standard/document that the 0.8mil value was extracted from? You also make reference to thin PCBs. What is the associated thickness value for thin PCBs? I am old school and think of PCB thickness of 0.068mil. Is there a relationship between the thickness of the PCB and the PTH knee value. Victor, -----Original Message----- From: TechNet [mailto:[log in to unmask]] On Behalf Of Werner Engelmaier /* Sent: Wednesday, July 08, 2009 11:43 AM To: [log in to unmask] Subject: Re: [TN] LF PTH, Knee copper thickness measurement Hi Victor, The 0.8mil Cu standard does not work with Pb-free for 2 reasons except for thin PCBs. Too thin for the PTH barrel integrity with those large thermal expansions for any resin with Tg<190C, and too thin for reworks. Werner -----Original Message----- From: Victor Hernandez <[log in to unmask]> To: [log in to unmask] Sent: Wed, Jul 8, 2009 8:49 am Subject: [TN] LF PTH, Knee copper thickness measurement Fellow ThecNetters: Can someone share their experience in measuring the Lead Free PTH copper thickness at the knee for first pass assemblies and then after 1x and 2x rework. This especially true on the solder side of the board. I have reviewed the IPC-A-600F standard and did not find a method/technique. I believe the preferred minimum thickness is 0.5 mils for 2x rework. Victor, --------------------------------------------------- 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 -----------------------------------------------------