Bob,
When BlackBerry was still an electronics manufacturer, it used the misting systems. They are great IF:
1) They are properly maintained.
2) The water source is RO or distilled water.

Now my lab had a separate misting system and the people who put it in place took, say we say, a couple of short cuts and the result was the salt that was deposited on our x-ray system incapacitated it.  My group had to use ion chromatography to track down where in the system the installers screwed up.  Sigh.

Regards,
Bev

Sent from Mail for Windows 10

From: Bob Wettermann
Sent: Tuesday, January 30, 2018 10:17 AM
To: [log in to unmask]
Subject: [TN] Solder Paste and RH-Both Winter Dryness and Tropical Humidity Conditions

Dear Technetters:

Since it is winter in Chicago and much of the northern realms, the RH
values are getting under 20% when the heat is on.

Outside of ESD issues, board assemblers have the issues of solder paste
drying out and not having enough active flux during the reflow cycle. This
can even happen with WS fluxes that are very active.

There are a handful of CMs in the great northern realms of MI, NY, MN and
WI that are using misting systems (that come with their own set of
problems) to keep the RH values higher in the winter months.

What are others doing (outside of monitoring) to deal with this issue and
solder paste printing?

The opposite can be true on those very humid summer days when the past
slumps easily.

Thanks!
-- 
Bob Wettermann
BEST Inc