Some possibles you may wish to check on:
1. Solder joint cooling rate: slow cooling will result in large crystals
(coarse grain structure) of the solder alloy components, resulting in a 'dull'
look. See paper by Livingstone & Weed given at NWC, China Lake on this issue.
This work done on military pwas that were vapor phase soldered using rosin
fluxes. Accelerating the cooling rate gave smaller grain structure, thus
'shiny' joints.
2. Use a mild alkaline pre-wash/wash to neutralize any residual acidic flux
residues to prevent 'micro-etching' of the solder surface. See paper by Cala
on this subject given at NEPCON West.
Bill Kenyon
Global Centre Consulting
3336 Birmingham Drive
Fort Collins, CO 80526
Tel: 970.207.9586 Cell: 970.980.6373
************************************** Get a sneak peak of the all-new AOL at
http://discover.aol.com/memed/aolcom30tour
---------------------------------------------------
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
-----------------------------------------------------
