<<  For those of you who still use RMA flux - what are you using to clean
your 
 boards?  Should boards being cleaned with HCFCs be labelled (Montreal 
 Protocol)?
  
 Ellen Berkman
 Excalibur Systems >>

Ellen,
Our lab deals with a wide variety of processes, including low solids, water
solubles, and traditional high solids RMAs, usually from a residue
standpoint.  There are still a wide variety of processes being used and a
number of manufacturers are remaining with high solids RMAs, due to the
protection afforded by all that rosin.  Most of the customers that we deal
with who are still using HCFCs are looking to get out of them quickly.  The
increasingly hard line taken by the EPA on HCFCs makes this a very
unattractive option.  You would have to contact the EPA to determine if HCFC
cleaned assemblies are included in the CFC Labelling Law.  Perhaps another
individual on this forum could comment on that aspect.  I don't deal with the
Labelling Law much.

Some few manufacturers are still using Freon or trike, but are scrambling
like crazy to get out of it; they can't buy it anymore (imagine that).
 Petroferm seems to have a drop in replacement for vapor degreasers involving
their co-solvent/HFE blends.  From the data I have seen (SMI 96, Dr. Mike
Hayes), it appears to be a viable material, but the HFEs may be classed as a
global warming material, and so targeted by the EPA.  In addition, I am not a
big fan of vapor degreasing as a cleaning method, but hey, if it works for
you.......

Some manufacturers, primarily defense contactors with existing contracts, are
using semi-aqueous cleaning, mostly with Axarel 32 and Bioact EC-7R, both
carried now by Petroferm.  Larger firms use an in-line, smaller firms a batch
cleaner.  Like any cleaning method, they are good if you know what you are
doing.

There are other semi-aqueous cleaners on the market, but I see these the
most.

>From my perspective, most people who are using high solids (<15%) RMAs are
using aqueous cleaning, usually with a saponifier material.  The four
saponifiers I see most are Envirosense Envirogold 816, Kyzen Aquanox SSA,
Dwight and Church Armakleen, and Alpha 2110.  I have my own prejudices where
these materials are concerned, more suited to an off-line discussion
(wouldn't want any commercials, would we?).  

If I had to pick a cleaning method, from everything available, I would choose
aqueous cleaning with deionized water and a good saponifier.  Deionized water
is a must (in my opinion) and a saponifier with a good surfactant package can
break down the surface tension problems inherent with pure water.  The
surface tension of water can prevent water from getting under low standoff
components (I don't care how high the water pressure is).  I have also used
this approach with several clients to remedially clean contaminated bare
boards.

I hope this has been of some help.  Contact me if you would like to go into
greater depth.

Doug Pauls
Technical Director
Contamination Studies Labs
[log in to unmask]
(317) 457-8095
EIEIO

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