Commonly done. But, recommend that the segregation of fluxes be carefully
enforced and that the cleanliness level resulting from the cleaning
operation be controlled to avoid compatibility failures from residuals. I
would also recommend testing cleanliness after cleaning and then as an
experiment test again some time later. You might be surprised what will show
up.
The enforcement issue in production is a difficult one, since operators will
often use what works best for their soldering operation. The stronger fluxes
migrate throughout the production area.
Mel Parrish
Director, Training Materials Resources
Soldering Technology International
102 Tribble Drive
Madison, AL 35758
256 705 5530
256 705 5538 Fax
[log in to unmask]
www.solderingtech.com
-----Original Message-----
From: TechNet [mailto:[log in to unmask]]On Behalf Of Tom Parkinson -
Quality System Manager - WinTronics, Inc.
Sent: Tuesday, March 11, 2003 10:39 AM
To: [log in to unmask]
Subject: Re: [TN] Mixing fluxes - more
I've read the recent questions and information concerning mixing of
fluxes. I agree - do not mix flux types when soldering. However,
here's one for you that can be looked at from a couple of angles....
1. I build a board - wave solder using washable flux. Flux is
activated, does it's thing, and board is soldered.
2. Water Wash and Dry the board. All washable flux residue is gone.
3. Add a couple of more components that CANNOT be washed (water will
enter the component and ruin it), using NO-CLEAN.
4. Board is done.
Technically, I have used 2 types of fluxes on one assembly....
Another scenario:
1. Board (described above) is finished. But, fails test - I find a bad
component...
2. I have to use NO CLEAN to replace the component because I cannot
water wash the board (remember the other components that cannot be
subjected to water wash..)
3. Board is done. Passes test - finished.
Again - Technically, I have mixed fluxes on the same assembly.
In the above description, I do not see a problem - or am I missing
something?
Thanks,
Tom
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