Gerard O'Brien wrote:
>         2.dip and look tests do not yield wetting speed data, impact of
> temperature on wetting speed/force, show de-wetting ( Brian E - I have
> unfortunately many thousand curves showing dewetting which upon further
> analysis was confirmed as poor basis metal pre-treatment)

Whereas I agree with you that dewetting is most often caused by poor
preparation of the base metal (usually either the presence of organics,
such as bleed-through and/or the use of abrasives), I don't understand
your other contentions. Edge-dip tests, such as I described, done under
scientifically regulated and repeatable conditions, do yield wetting
speed data and they show dewetting better than any other method. If you
change the solder bath temp, you could also determine the effect on
wetting speed. Maybe you are confusing what I was describing with the
IPC edge-dip test with the cam-driven arm, which had a dwell time (4
sec, if I remember correctly) that would be useless for wetting time
determination although excellent for dewetting.

In the 1960s, I did about three years (intermittent) research into the
causes and cures for dewetting, as this was a real pest at that time.

Brian

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