Back in the fall '06 I emailed the forum about how to
qualify pcb laminates for the higher temperature required
by Lead Free assembly.

One of the suggestions out of the many responses was
"a cyclic T260 (cT260) protocol where a material is thermal
cycled to 260 6 times, to simulate assembly "

The Manf. Engineer went out and had our CM run a 14 layer  FR-408 material
pcb with via filler through this profile 6 times:

http://stevezeva.homestead.com/files/Lead_Free_Profile_V_Sample.pdf


The cross section came back looking like these:
http://stevezeva.homestead.com/files/cross_section_1_via_fill.jpg

http://stevezeva.homestead.com/files/cross_section_2_via_fill.jpg


I need some help and opinions on what I am looking at.

The first thing I noticed was that the reflow profile never gets the
temperature higher than 249C in one location. And the time above this
temperature seems short to me. With most of the time above only 217C.
Lower than I would think is need for Lead Free reflow.


Second, The cross sections look fine to me. I don't see anything 
coming apart or bulging. I'm I missing something?

I'm looking to go back to the Manf. Engineer and comment on this
test. I'm think that this is a nice test of low temperature reflow. 


Thanks to Steve and his wonderful web page of knowledge.

Thanks to all in advance.

Dave Seymour


-- 
Dave Seymour, CID+
Catapult Communications Inc.
800 Perimeter Park Dr, Suite A
Morrisville, NC 27560

Direct: (919)653-4249
Main: (919)653-4180
Fax: (919)653-4297

[log in to unmask]







*********************************************************************************************************
"This e-mail (and any attachments) is confidential and privileged information of Catapult Communications"
*********************************************************************************************************

---------------------------------------------------
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
-----------------------------------------------------