We qualify our solder pastes to understand what their environmental performance characteristics are, and accordingly we ensure room temperature/humidity is fully monitored and controlled at all times. It’s a no-brainer, required by J-STD-001.

And we understand the issues with a humidifying system and have fixed those, as proven by our Maintenance Procedures and results thereof.



-----Original Message-----

From: TechNet [mailto:[log in to unmask]] On Behalf Of Bob Wettermann

Sent: Tuesday, January 30, 2018 9:18 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