My company is making a slow transition to No Clean chemistry in our SMT,
Wave, and Post Wave operations.

 We are taking a systematic approach and thought we were on a smooth
path until I ran across a June 1992 article published in Circuit
Assembly and authored by several Engineers at the Foxboro Company
(Foxboro, MA).

The article was written specifically about No Clean materials  and it
warns about "incompatibilities between similar solder flux products
supplied by different vendors." The conclusion is rather frightening
"The potential for intermittent and ultimately catastrophic failure of a
circuit over time due to flux incompatibility is cause for serious
concern."

I have contacted several industry experts and all downplay the
significance of compatibility issues, although none have performed
independent testing to qualify their "opinions".

Does anyone have any first hand experience with No Clean flux
incompatibilities?  Additionally, is there any material published on
this subject other than the one I ran across?

Barring any new information, I am prepared to undertake a regimen of
testing which will verify the compatibility of the No Clean materials
which are currently approved by MPI.  The testing will be similar to
that performed in the Foxboro article ( SIR using IPC-B-25 coupons, 40
degrees C/95% RH, 30 V bias, measured incrementally during the 8 week
cycle).


Ted Labowski
Vice President - Quality
Microboard Processing, Inc.

Email : [log in to unmask]

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