Hello Experts,

I'm monitoring this forum for a while now and thankfully could learn a lot
of your expertise.  Since I can't claim beeing expert myself in this arena
my return is much less.
We just ran into the issue that our assembly house mixed up solder pastes
and soldered lead containing BGA's with LF paste. Despite the assembly
house assured that they have used Sn/Pb paste I could show that the solder
joints are LF (with the help of lead test sticks I first heard of in this
forum).
This made me think for a method how it may be possible to distinguish
between LF and lead containing pastes easily already in the printing phase
of the paste to the PCB. Has anybody of you spent any thoughts about this?
What came to my mind was that maybe LF pastes could have some adds that
let them appear in a color, green for example, instead of the metallic
grey. These adds may can evaporate during reflow or even better remain in
the solder to have colored joints on LF boards and metallic grey joints on
Sn/Pb boards. Would this be an option?

Thanks for your thoughts,
Emanuel

---
MPL AG                                   www.mpl.ch
Emanuel Zimmermann       [log in to unmask]
Manager R&D                       Phone: +41 56 483'34'34
Taefernstrasse 20               Fax:      +41 56 493'30'20

CH-5405 Daettwil
---

-------------------------------------------------------------------------------Leadfee Mail List provided as a service by IPC using LISTSERV 1.8d
To unsubscribe, send a message to [log in to unmask] with following text in
the BODY (NOT the subject field): SIGNOFF Leadfree
To temporarily stop/(start) delivery of Leadree for vacation breaks send: SET Leadfree NOMAIL/(MAIL)
Search previous postings 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
-------------------------------------------------------------------------------