Howard,
We
experienced some of your pain when we ran our process without Nitrogen.
Are you using Nitrogen during your reflow ovens?
In the wave, some of the no-clean flux is
98% water. The thermodynamics involve mostly getting rid of
the water prior to entering the solder pot to ensure adequate pre-heat
temperature as well as ensuring that all the water is boiled-off in order to
avoid solder explosions and their consequent results evidenced by masses of
solder balls at the perimeters of solder openings in the
pallet.
Hope
this helps any..
Michael
Laroe
Mfg.
Engineer
MSL-Lowell
(978)677-2977
(v)
(978)454-9200
(f)
Hi
all,
There is a presumption (not
supported with data) here that when it rains, and the humidity goes up, we
historically have experienced more solder defects. I realize that
humidity can affect MSD's and PCB's, but what, if any, would be the symptom of
high humidity, in terms of solder joint defects at wave and reflow (solder
balls,voids)? Our process is strictly no-clean. Normally, the
humidity in our plant is 10-30%, and when it is high, it's in the 50-60%
range, which is probably not even that high compared to some of your plants
located in humid climates. I suspect that our problem may be something
other than the humidity.
Also, we
don't bake our PCB's, and I'm not sure if it's necessary.
Howard Watson
SMT Manufacturing
Engineer
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