Jim, do you are assembler or pcb-manufacturer?
For the assembler's in-house processes see J-STD-001B, 8.3.4 and 8.3.5 and
8.3.9:
* 8.3.4 means you (or your customers) have to define the the
cleanliness. If there are no binding demands, I would suggest to use 8.3.5
or 8.3.9.
* If do you need a quantitative test for flux residues: 8.3.5 refers
to IPC-TM-650, TM 2.3.27. A real quantitative test: extraction of
contaminats by using a soxhlet, determine the flux amount by UV-spectroscopy
(facing to pure flux as reference)
* 8.3.9 refers to IPC-TM-650, TM 2.3.38 (similar, but only visual
detection).
So, out of J-STD-001B is no reference to IPC-TM-650, TM 2.3.39.
But IPC-HDBK-001, 8.3.4.5 and IPC-HDBK-001, 8.4.5 (which explains
J-STD-001B, 8.3.9) mention FR-IR and refers to "your" IPC-TM-650, TM 2.3.39.
What's the reason to use TM 2.3.39? Do you apply conformal coating (or
potting)? Then there would be a need to test the organic contaminants.
Otherwise I'm not sure org. resid. test are needed, or sure not by FT-IR.
For the pcb-manufacturer see IPC-6012, 3.11.2: " (...) shall be tested in
accordance with (..) 2.3.38 or 2.3.39". This means you could make your life
easier by using 2.3.38. However, IPC-6012, 4.2 refers to table 4-3, and for
3.11.2 you can read: "Special Requirements (when specified) As specified by
contract or master drawing".
General, for dendrite growth see more for the ionic testing paragraphs.
Enough confusion?
Bernhard
> -----Ursprüngliche Nachricht-----
> Von: Walton, Jim [SMTP:[log in to unmask]]
> Gesendet am: Donnerstag, 2. Dezember 1999 21:37
> An: [log in to unmask]
> Betreff: [DC] IPC Ionic test
>
> Hey everyone,
>
> Has anyone come to a conclusion when using IPC-tm-650 number 2.3.39? Item
> 6.8 clearly avoids any usable answer. I am looking for max. acceptable
> levels of contaminants for bare boards (incoming from the fab house) and
> assembled boards (before they are shipped from our dock). How about a
> listing of severity of certain contaminants as they pertain to dendrite
> growth on pcbs? I have test results, but I'm not a chemist so I am having
> a
> hard time coming up with definitive answers to what is "bad" and what can
> pass.
> I know there must be "real world" experienced people out there that can
> help.
>
>
> TIA
>
> Jim Walton
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