Semiaqueous
Case Studies
FMC Corporation, Naval Systems Division, has eliminated its use of 1,1,1 -trichloroethane in manufacturing
naval weapons handling systems. Alkaline detergents are now used for much of the cleaning. Isopropyl alcohol
replaced TCA in foundry operations. Steam degreasing and semiaqueous cleaners are now used in the plating
operations. Elimination of the TCA resulted in a net savings of $29,000 per year from 1991 levels. Isopropyl
alcohol also replaced CFC-113 in the wave solder cleaning of printed circuit boards, reducing the purchase of
CFC-113 by 5,500 lbs annually, and saving FMC $15,000 in chemical purchases.
Douglas L. Hildre, Environmental Control Manager, FMC Corporation, Naval Systems Division, 4800 East River
Road, Fridley, MN, 55421 MnTAP, 1993 Governor's Awards for Excellence in Pollution Prevention.
AT&T has reduced its usage of CFC-113 by switching to a semi-aqueous chemistry for cleaning surface mount
assemblies. Parts are fed by conveyor into a power washer consisting of wash and rinse/dry modules. Low and high
pressure sprays of a terpene cleaner are followed by nitrogen knives which reduce cleaning solution dragout and
blanket the washer with an inert atmosphere. In the second module, the parts are rinsed with low, then high
pressure water sprays to remove the terpene cleaner. Rinsing is followed by water removal by air knives within
the same module. Care must be taken in selecting surface mount components because the terpene cleaner swells
some plastics and elastomers. AT&T has found that the new cleaning method is more economical than the
previous CFC-113 method.
Terpene Cleaning of Surface Mount Assemblies, Aqueous and Semi-Aqueous Alternatives for CFC-113 and
Methyl Chloroform Cleaning of Printed Circuit Board Assemblies, EPA/400/1-91/016, June 1991, pp. 51-60.
Landis and Gyr, a Swiss-owned company in Lafayette, IN, manufactures watt-hour meters for utility companies.
Both rosin and organic acid fluxes are removed during the manufacturing process. They replaced two cleaning
lines (solvent and aqueous) with one semiaqueous cleaning line. Ionic cleanliness levels for the semiaqueous
system are better than for either of the systems it replaced. Landis and Gyr likes the convenience of cleaning
everything on one line.
DuPont Customer Service Center. 1992. Landis and Gyr Replaces Two Cleaning Systems with Axarel 32
Cleaning Agent. Wilmington, DE, July.
The Maintenance Group of Conoco Northern Area Marland District Pipeline is using a semiaqueous cleaner as a
replacement for Stoddard solvent in general cleaning and degreasing. No changes in cleaning procedure were
necessary. Stoddard solvent required disposal as a hazardous material. The semiaqueous cleaner used may meet the
criteria for inclusion in used oil reclamation.
DuPont Customer Service Center. 1992. Axarel 6000 Cleaning Agent Cuts Oil Along the Conoco Pipeline.
Wilmington, DE, July.
AT&T Bell Laboratories had been using CFC-113 in an ultrasonic bath to remove machining and stamping oils
from circuit board backplane pins. Prior to plating, the pins were immersed in a caustic bath to remove all traces
of oil and dirt accumulated during storage. The cleaning system now consists of one semiaqueous process using
aliphatic esters. AT&T Bell Labs, Kansas City, has eliminated the use of ozone depleting solvents and a caustic
bath. The system is cost competitive.
Gillum, William O., and Anna M. Jackson (AT&T Bell Laboratories). 1991. CFC and Halon Alternatives
Conference, Baltimore, MD, pp. 40-48.
TRW manufactures electronic assemblies for the space and defense sector in its California plants. RMA flux is
now removed using a semi-aqueous chemistry in a batch spray cleaner. This cleaning method replaces about 90%
of the vapor degreasing with CFC-113. Until 1993, TRW had been using CFC-113 at the rate of 300K lbs/yr.
The new method will use an estimated 20 drums of cleaner per year to replenish 5 semi-aqueous cleaning units.
The current cost of the semi-aqueous cleaner is $250/55 gal drum. In addition to reducing CFC-113 usage by 90%,
with its associated disposal costs, the new semi-aqueous method is producing cleaner electronic assemblies. The
waste SA cleaner qualifies as a fuel blend, lowering disposal costs. Cleaning cycle times have increased due to the
drying required. Because the plants are producing relatively small quantities of high quality components, the
increased cycle time has not been a significant factor.
Hernando E. Arauco/TRW, "CFC Solvent Elimination in ETD", presented at the 1993 Solvent Substitution
Conference, Phoenix, AZ, Dec.93. Hernando E. Arauco/TRW, telephone conversation with K.D. Carter/RTI,
Feb.94
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