Ken

By your posting you have the answer - yes, or so it would seem.

Consider, the test method is measuring the amount of ionic contamination
present on the item under test. The question is what is an acceptable level
of NaCl equivalence as produced from this test - and that is entirely
dependant upon your application, circuit design etc..

A level of <1.5microgrammes of NaCl equivalence has been used as a go/no go
condition, but this is wrong. Why? Because it also means that it is
acceptable to leave up to 1.5mg of salt on every square centimetre of your
assembly; but If you are producing fine-line, fine-pitch with modern COB
components, then this level will, almost surely, be far too high.

As Brian stated, this testing method has been grossly misused. It really
should only be used to track your process conditions, not to determine how
clean is clean.

As to whether no-clean fluxes leave harmful residues....oh you bet they do,
but that's OK if you keep within YOUR own acceptable limits as defined by
other perhaps more rigorous test methods. How carefully do you control the
amount of flux applied onto the assembly if you wave solder?

I hope this helps - but if you are seeing this level of ionic contamination
then this is not a good thing!

Finally, many producers to my knowledge employ a go/no go of
<0.2microgrammes per cm/squared.

> Does NO Clean processed parts show more ionic contamination than aqueous
> processed parts when measured using ionograph? We are seeing third party
> part showing 50 plus microgram of NaCl per square inch. Is there a different
> ionograph measurement standard for No clean v/s aqueous washed (9.67
> microgram of NaCl per square inch)? Is there an IPC/industry spec for No
> clean processed parts?
>
> Re,
> Ken Patel
>
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