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Date: | Fri, 07 Feb 97 07:26:08 cst |
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Good Morning TechNet!
(or good evening depending on which side of the planet you're on!)
The white haze you are observing could be MANY things - not all low
residue pastes are clear after the reflow process. Get a copy of your
flux technical data sheet, review it and then start asking your flux
vendor questions on the characteristics of the flux versus the process
parameters (temperatures,equipment, times, etc.) that you are using.
Tin oxide is not always bad, just depends where on the assembly you
find it (every assembly containing tin/lead solder has tin oxide!).
Give Doug Pauls at CSL a call ([log in to unmask]) - he can relate some
different scenarios that may relate to your flux chemistry and
process. Good Luck.
Dave Hillman
Rockwell Collins
[log in to unmask]
______________________________ Reply Separator _________________________________
Subject: No clean paste
Author: [log in to unmask] at ccmgw1
Date: 2/7/97 3:55 AM
Anyone,
I have been told that a no clean paste post curing
will leave a white haze or residue around the well.
And, that this haze is a TIN OXIDE. My question
is: Is this ok? Should we be concerned? What
chemistries could react with TnO2 causing corrosion?
My experience is oxide can be hazardous to the
assembly, i.e. corrosion, tin wiskers etc.
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