Electronics Forum | Wed Aug 27 09:29:10 EDT 2008 | blnorman
I read somewhere there is a thermal measure that takes into account Tg and Td. Offhand I can't remember what it is, does anybody know what I'm talking about?
Electronics Forum | Wed Aug 27 13:08:30 EDT 2008 | vladig
Td - is the degradation temperature for a laminate (board), while Tg - is glass transition one. There is one more (even more important) - delta Tg. They characterize the quality of the laminate material. Regards, Vlad www.sentec.ca
Electronics Forum | Wed Aug 27 17:50:48 EDT 2008 | blnorman
I know, but somewhere I read about an equation or relationship that takes both into account to generate another number.
Electronics Forum | Wed Aug 27 22:03:16 EDT 2008 | vladig
Yep, that is probably the one in the Werner's paper. Vlad www.sentec.ca
Electronics Forum | Thu Aug 28 11:15:08 EDT 2008 | blnorman
BINGO. I knew there was some relationship between the 2, thanks guys.
Electronics Forum | Wed Aug 27 21:22:44 EDT 2008 | davef
While you're waiting for others to reply, here are a couple of previous postings from the fine SMTnet Archives: * http://www.smtnet.com/forums/Index.cfm?CFApp=1&Message_ID=45013 * http://www.smtnet.com/forums/Index.cfm?CFApp=1&Message_ID=50312
Electronics Forum | Mon Dec 19 07:29:30 EST 2005 | jax
Tg is just a way to say when the board goes limp... or a quick way to rank laminates... who cares. For lead free you want to look at Td, Decomposition Temperatures. ( Temp at which the material weight changes by 5% )
Electronics Forum | Mon Dec 19 07:49:33 EST 2005 | davef
=330*C is good advice. Search the fine SMTnet Archives for earlier discussions on Td, like http://www.smtnet.com/forums/Index.cfm?CFApp=1&Message_ID=32430
Electronics Forum | Mon Nov 20 10:40:35 EST 2006 | SWAG
Thanks Mark and Dave. It sounds like our board design and problem areas are similar to yours, Mark. We talked with our customer about the grid pattern but I'm not sure where we are at with that. In reference to the Tg/Td thread, the material is a
Electronics Forum | Thu May 08 12:11:30 EDT 2008 | boardhouse
Hi Wayne, I am just curious what material is being called out. Are you just specing FR4 or are you calling out a particular IPC 4101 / Some recommended laminates designed for Lead free assembly are: Isola 370HR Nelco 4000-11 or 4000-29 Iteq IT15
