All the listed materials are good at LF temps; however, they are all high Dk/Df. If you need a low loss or low Dk material (otherwise why use FR408), then they won't be good substitutes. The Nelco 4000-13EP is comparable or even more favorable for loss. We have been successful on a number of mid-temp assemblies (ie: 245C) with this material, including ones which were trouble before switching over. You could also look at Isola's IS415 which is low loss, but not low Dk. I think it was developed to fit into the FR408 space. We have done some protos with it and had no issues, but have not yet ramped it to volume (although we plan to on a new part). You're mileage may vary. You will need to run a simulation reflow on your specific part. Regards, Valerie "Whittaker, Dewey (EHCOE)" <[log in to unmask]> Sent by: TechNet <[log in to unmask]> 03/12/2007 12:45 PM To [log in to unmask] cc Subject Re: [TN] Laminate material selection IMHO and having assessed many, many things given the known variables and needed process controls or the lack there-of, I would only use the following: * Polyclad 370 HR * Panasonic R-1755 * Nelco N4000-29 Dewey -----Original Message----- From: TechNet [mailto:[log in to unmask]] On Behalf Of Marsico, James Sent: Monday, March 12, 2007 5:31 AM To: [log in to unmask] Subject: [TN] Laminate material selection Hello Technet: Can anyone provide the pros and cons with using Nelco N4000-13EP vs. Isola FR408 with regard to PWB processing, reliability and performance for a high reliability application? How would these compare with a polyimide material? Thanks in advance, Jim Marsico EDO Corporation 1250 New Horizons Blvd. North Amityville, NY 11701 631-630-5079 [log in to unmask] ------------------------------------------------ --------------------------------------------------- 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 -----------------------------------------------------