Is it possible the pattern has redundant chains supporting continuity after some have cracked? Cracked barrels generally produce resistance levels well above 5%. Jeffrey Bush Director, Quality Assurance and Technical Support VERMONT CIRCUITS INCORPORATED 76 Technology Drive - POB 1890 Brattleboro, Vermont 05302 Voice - 802.257.4571 ext 21 Fax - 802.257.0011 <http://www.vtcircuits.com/> -----Original Message----- From: TechNet [mailto:[log in to unmask]] On Behalf Of christian ge Sent: Tuesday, May 23, 2006 2:53 AM To: [log in to unmask] Subject: [TN] Thermal cycle test for plated through holes filled with epoxy ink and cap plated on the top Hello Technetters, I need your help on the following thermal cycle test problem. Recently we asked our PCB suppliers to do 1000 cycle thermal cycle test for 6L, daisy chain boards with plated through holes filled with epoxy ink and cap plated on the top of the holes( or via-in-pad design). The resistance change before and after thermal cycle test is less than 5%, however the holes have complete barrel crack. Have you seen this kind of problem before? Can I approve the supplier's test result? Here are some more information about the test for your reference. 1) board thickness: 1mm (40mils) 2) hole size: 20mils, 18mils, 15mils, 10mils. All have complet barrel crack except the holes of 10mils . Thanks for your help in advance! Chris __________________________________________________ ¸Ï¿ì×¢²áÑÅ»¢³¬´óÈÝÁ¿Ãâ·ÑÓÊÏä? --------------------------------------------------- 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 ----------------------------------------------------- http://cn.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 -----------------------------------------------------