Hello again .. Good morning,
**Good morning Tugmen

**Hi Doug Pauls (thank you very much for your answers)
***You're welcome.

Below you could find one more question that is really important.
**Actually, it appears to be seven more questions that are really
important.

"Do you please check if the following process can be sufficient to
eliminate all the risks which is coming from the use of H type flux;
After completing the soldering process;

**Well, there is no such thing as eliminating all risks.  Not even the most
rapid six sigma double black belt recent convert hopped up on opium guru
can say that.  Well, maybe after being hopped up on opium......


1. "well done" cleaning with water,

**use 140-150F RO water as a minimum for first knock off rinse.  Then hot
(140-150F) deionized water thereafter.  Use a saponifier to reduce the
surface tension so you can clean in fine pitch areas and under BGAs.

2. visual inspection for detecting the flux residues and checking corrosion
and dendritic formation,

**with a type H flux, many of your residues will be invisible.

3. performing the ionic contamination testing,

**Bulk Ionic cleanliness testers won't save you.  Ion Chromatography might.
Long term burn in testing in humidity will catch failures.

4. conformal coating application

**Coating won't save you if cleanliness is not adequate.  Like putting a
bandage over an infected wound.

5. visual inspection for checking corrosion, dendritic formation and
mealing of conformal
coating,

**Hope you don't have BGAs or low profile components.  Pretty hard to
inspect under them.

6. burn-in testing,

**Good idea.  Make sure it is in humidity. A dry environment does not show
corrosion or dendritic growth mechanisms.
7. vibration testing (at least in the two axises)"

**Has no relation to the use of type H flux.  Vibe won't show you anything
other than solder joint reliability.

**My friend, I have two suggestions:  first, get yourself a copy of
IPC-HDBK-001, the companion to IPC J-STD-001.  It has a wealth of
information on it about fluxes, cleaning, conformal coating, etc.  I really
like the way the section on cleaning is written (not a word from you
Dewey). It appears you are looking for a basic primer on electronics
manufacturing, and the Handbook is it.  Second, since you have these basic
questions about manufacturing and residues, and we all have to start our
trek for knowledge somewhere, I would suggest that you are not ready for
the challenges of a type H flux.  Kind of like giving a Ferarri to a 16
year old, or Dewey.  If you find that you have such poor solderability of
boards that you think you need a type H flux, I suggest you put your effort
into working with your board fabricator or your board storage people to
remedy that problem.  Far easier than implementing the controls in
assembly.

Thanks in advance.
**You're welcome, after the fact.

Doug Pauls

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