The subject of bath life of saponifier chemistries has led to some
interesting discussion.  I would like to add the following:

1.  The selection of a wash chemistry in the processes I am responsible for
included the availability of a useable, effective check on where my wash
tank concentration was and how my bath life was holding up.  At the time of
my initial selection of chemistry in 1993, nobody who tried to sell me Juice
had good answers.  

2.  As a result, the in-line cleaner I selected was equipped to run the top
three leading contenders as well as old fashioned MEA based chemistry.  I
quickly informed my Juice supplier that our longterm relationship would be
based on continued product improvement and research into defining
methodologies for predicting End of Life for my wash bath. 

3. As a result, I have the ability today to send weekly samples to establish
both the concentration and the flux loading.  We have established a ratio
between the concentration and flux loading where cleaning performance drops
significantly. 

4. Process control is achieved by use weekly readings coupled with daily
refractometer readings to ensure that the bath is in control.  The cleaner
is equipped with automatic chemical injection based on gallons of make-up
water.  

The decision on the best process chemistry is a hard one.  The best cleaning
material is not the best choice if it is an uncontrollable process.  Bath
life for my chemistry was also important, and is currently averaging over
three months.  Cleaning of rosin type assemblies is declining, but we clean
100-400 CCAs per day from wave or reflow, plus handsolder & rework and
precoat cleaning as well.

My chemistry supplier is my partner.  So is my equipment manufacturer.  And
I let them pull their weight.  I find that my best partners lead to my best
process.

Good Luck, Steve Mikell, Process Engineer, Soldering & Cleaning
SCI Systems, Government Division, Plant 13
[log in to unmask]
Steve Mikell, Process Engineer, Soldering & cleaning processes
SCI Systems Plant 13
[log in to unmask]