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| Reply To: | TechNet E-Mail Forum. |
| Date: | Mon, 25 Jan 1999 11:09:37 EST |
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In a message dated 1/25/99 7:50:34 AM Pacific Standard Time,
[log in to unmask] writes:
<< As you all know. We are getting into doing a basic BGA assembly. The new
question which came up is, since we run a water soluble flux paste. How are
we going to know if it is clean under the BGA?? Any suggestions beside
going to a no clean paste??
Thanks in advance.
John >>
Mornin' John...
Ionograph is one way...won't catch everything, but it'll tell ya' if you
got flux residues on your board...but then again, it doesn't really pin point
if it's from beneath the BGA. SIR testing is another, but that takes a while
though.
If you wanna get a "warm n fuzzy" that your cleaner is capable of doing
the job. One thing you can do is what I was taught when selecting a cleaner to
buy, is get yourself some glass plates (heat resistant tempered glass to be
sure!) and make yourself up some glass slugs, or chips if you will, that are
the same size as the largest BGA you think you'll do. Glue them to the glass
plate at different stand-off heights and squirt some colored flux beneath the
slugs. Send it through a reflow oven to bake it some, and then it's bathtime!
Then just take a gander at what the plate looks like after it comes out of
your cleaner. That'll show you without a doubt, what your cleaner is capable
of.
-Steve Gregory-
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