Neutral Aqueous
Case Studies
SAAB, a Swedish automobile manufacturer, uses a high-pressure cold water spray to clean aluminum engine
cylinder heads after machining. No detergent additives are used to aid cleaning. The water does contain a small
amount of corrosion inhibitor. The water is filtered and reused. The water is pressurized to 4,000 psig and exits
the nozzles at 500 mph. The cleaning system produces one clean, dry cylinder head every 48 sec.
Cold Water Cleans Machined Parts, Tooling & Production, pp. 38-39, June 1989.
The Eaton Corporation of Spencer, Iowa, produces hydrostatic transmissions for heavy- and light-duty offroad
use. Four large vapor degreasers required the purchase of 25,000 gallons of TCA annually. They could not find a
suitable aqueous alternative for cleaning the oil-based lapping compound that was a major contaminant. Switching
to a water-miscible lapping compound solved this problem. Eaton now uses a low-pressure spray cleaner for many
of its parts. Cleaners and inhibitors are constantly being evaluated as new chemistries emerge. One Eaton
representative estimates that chlorinated solvent use has been reduced by 99% since 1987.
Alternatives to Solvents (Degreasing for the '90s, Solid and Hazardous Waste Education Center, University of
Wisconsin-Extension, Madison, WI.
Dayton Rogers Manufacturing Company, Minneapolis, MN, is a short-run metal stamping company founded in
1929. Dayton Rogers had been using a vapor degreaser to remove oil-based lubricants from metal parts prior to
deburring. Currently, Dayton Rogers is using a vibratory tumbler with aqueous cleaning solution to clean and
deburr 75% of its manufactured parts simultaneously. The remainder of the deburring is done with a wet sander,
which also cleans and deburrs simultaneously. Switching to a water-based lubricant facilitated cleaning. The
aqueous cleaning solution has a neutral pH and contains rust inhibitors when needed for steel parts. All of the
parts are air dried after deburring. Dayton Rogers has eliminated the annual purchase of 1,100 gallons of
1,1,1-trichloroethane (TCA). Capital cost was $9,000 for a wet sander and sheet-metal drier.
NET SAVINGS: $36,000 PER YEAR IN OPERATING COSTS.
Replacement of Vapor Degreasing Operation with Deburring Process for Cleaning Metal Parts, Case Study,
Minnesota Technical Assistance Program (MnTAP), Minneapolis, MN.
At the Smithville plant of ABB Power Transmission and Distribution Co., aqueous cleaning has replaced CFC
vapor degreasing. The distribution arrestors made here contain electrical contacts or gaps that must be clean and
tarnish-free. Various parts are stamped from aluminum, brass, and stainless steel using water-soluble lubricants. A
rotary tumbler containing the aqueous solution is used to clean the parts. After rinsing, the parts are
simultaneously polished and dried in a vibratory finisher containing cob meal media. The media is heated to speed
drying. The new process improves worker safety, eliminates CFCs, and costs less.
Alternatives to Solvents (Degreasing for the '90s, Solid and Hazardous Waste Education Center, University of
Wisconsin-Extension, Madison, WI.
Since 1988, Allied-Signal Aerospace in Kansas City, Missouri has used a volatile aqueous cleaner for wiping work
surfaces of laminar flow work stations, finger cots, latex gloves, and fixtures to remove light soils and
particulates. The volatile aqueous cleaner consists of 12.5% isopropyl alcohol, 0.82% surfactant, and the
remainder is deionized water.
The solvent removes both organic and inorganic soils. The previous solvent, CFC-113, was consumed at the rate
of 2000 lb/month and has been completely eliminated for wiping. The volatile aqueous cleaner is also used in
ultrasonic baths to clean complicated machined assemblies. Allied-Signal Aerospace reports better cleaning and
lower cost, about $1.00/gallon.
Hand, Tom and Bohnert, George/Allied-Signal Aerospace, Case Study #3: Development and Use of a Volatile
Aqueous Cleaner, EPA/ICOLP Eliminating CFC-113 and Methyl Chloroform in Aircraft Maintenance
Procedures, EPA-430 -B-93-006, October 1993, pp. 161-162.
At the US Department of Energy's Rocky Flats Plant in Colorado, water -based cleaners have replaced TCA and
CFC-113 for cleaning in non -plutonium areas. Water has also replaced CFC-113 for determining the density of
uranium.
Ficklin, Ann C. and Gordon R. Hicks, Materials Substitution at the Rocky Flats Plant, The Environmental
Challenge of the 1990's Proceedings of the International Conference on Pollution Prevention: Clean
Technologies & Clean Products, Risk Reduction Engineering Laboratory, Office of Research and Development,
US EPA, Cincinnati, OH, June 10-13, 1990, p. 263.
Bull HN Information Systems, Inc. in Brighton, MA manufactures printed circuit boards. They have replaced
TCA and methylene chloride with water -based systems for cleaning and stripping.
Printed Circuit Board Manufacturer Reduces Air Emissions, Wastewater Discharge, Sludge, and Chemical Waste
Through Process Changes, Equipment Modifications, and Recycling, American Electroplaters and Surface
Finishers Society, Inc. and US EPA, 12th AESF/EPA Conference on Environmental Control for the Surface
Finishing Industry, January 1991, pp.91-99.
Crown Equipment Corporation, New Bremen, OH, manufactures electric lift trucks and television antennae
rotors. Mild steel, aluminum, cast iron, and copper are all used and cleaned at the plant. In 1988 Crown used
208,000 lb. of TCA in cold cleaning (dipping) and vapor degreasing operations. Hand dipping now uses a
water-based cleaner with rust inhibitor added for corrosion resistance. 100% d-limonene spray cleaner has
replaced TCA for hand wiped parts. An alkaline aqueous immersion cleaner has replaced one degreaser (with
inhibitor added for ferrous parts). The other degreaser was replaced with an aqueous power washer which uses
heat, agitation, and forced air drying to produce clean parts. The payback period for the capital expenses was 10
months. In 1989 Crown saved $100,000 in chemical costs. Crown Equipment has switched to water -based
cleaning with no decrease in production. Employees prefer the water-based cleaner for hand dipping.
Kohler, Kurt, and Anthony Sasson, Case Studies: Multi-Industry Success Stories to Reduce TCA use in Ohio,
Pollution Prevention Review, Autumn 1993, pp. 407-409.
By switching to low volatility fountain solution, Neyler Color-Lith in Waukesha, Wisconsin reduced VOC
emissions in its pressroom by 95%. The new fountain solution which contains glycols, glycol ethers, and
surfactants allows increased use of water-based cleaners in the pressroom.
Pferdehirt, Wayne P., Roll the Presses But Hold the Wastes: P2 and the Printing Industry, Pollution Prevention
Review, Autumn 1993, p. 449.
|
