The issue is not Tg but Td. Some higher Tg materials actually perform worse than lower Tg materials. It is important develop a test program to validate your lead free process with specific base materials. Laminate manufactures offer some variety of thermally stable materials targeting lead-free, but these are used at a premium. If your lead-free process can be supported by existing base materials, than that is best economic solution. The test program will provide the feedback needed. Please contact me off-line if you need specific information on alternate base materials and Td for lead-free. Jeffrey Bush Director, Quality Assurance and Technical Support VERMONT CIRCUITS INCORPORATED 76 Technology Drive - POB 1890 Brattleboro, Vermont 05302 Voice: 802.257.4571.21 Fax: 802.257.0011 http://www.vtcircuits.com -----Original Message----- From: Black, Paul [mailto:[log in to unmask]] Sent: Wednesday, November 24, 2004 3:08 PM To: [log in to unmask] Subject: [TN] FR4 and Lead free Hi Tech Gurus, As people talk more and more about Lead free, I keep hearing that standard FR boards might not be able to take the extra heat required for a reliable Lead free solder joint. The problem is that I keep hearing the word MIGHT. I have not heard that this is definitely true and, if it is true, I have not heard anyone offer a cost effective solution. So, I am asking the many experts on this forum, will standard FR4 be able to handle the higher excursions (particularly, let's say, for a 7" X 9", 8 layer, double-sided SMT, .062" 5/5 board) associated with Lead free solder paste? If not, what would be the most cost-effective offering (i.e. high Tg FR4)? Thank you, Paul Black Manufacturing Engineer Kronos --------------------------------------------------- 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 -----------------------------------------------------