Pollution Prevention Case Study

Miller Electric
Manufacturing Company

Replacing Solvent-based Paints with Powder Paint
Standard Industrial Classification (SIC) Electric and gas welding and soldering equipment/3548
Type of Waste Paint-related solid and hazardous wastes; hazardous air emissions
Strategy Process line modification
Company Background Miller Electric Manufacturing Company of Appleton, Wisconsin, is the world's largest manufacturer of arc welding equipment and systems. Miller is a leading supplier to the metalworking, construction, and maintenance markets. Founded in 1929, the company employs over 1,600 people and operates one million square feet of manufacturing space in the Appleton area. The company was acquired by Illinois Tool Works, Inc. in 1993 and now operates as a wholly- owned subsidiary.
Original Process Metal parts were coated on a liquid painting conveyor line consisting of: five-stage parts washer; drying oven; four electrostatic disk applicator booths; four manual spray gun booths; and a curing oven. This system was installed in 1980.
Motivation The previous system used high-solids paint and achieved a relatively high transfer efficiency. However, Miller had concerns about future environmental regulations and wanted to reduce the costs of paint-related waste disposal. In 1994, nearly 30 tons of Volatile Organic Compound (VOC) air emissions were generated from liquid spray painting operations. Paint-related wastes were disposed of at a cost of approximately $20,000. In addition to environmental issues, Miller sought to improve the corrosion resistance of its painted parts.
Pollution Prevention Process Miller contacted a number of painting equipment suppliers to find an environmentally benign, high performance painting system. In late December of 1994, two powder booths were installed to replace the four electrostatic disk applicator booths. The two booths utilize 24 automatic and four manual guns. They are able to meet 80 percent of Miller's topcoat painting needs. The four manual spray booths were retained for painting low volume special colors.
Stage of Operations Complete and in operation
Level of Commercialization The technologies described here are commercially available
Material/Energy Balance Original Process
Feedstock
13,000 gallons per year of liquid paint

Waste & Disposal
60,000 pounds per year of paint-related wastes

Energy Use
330° F cure temperature using 2.4 million cubic feet/year of natural gas.

Pollution Prevention Process
Production increased approximately 5%.

Feedstock
80,000 pounds per year of powder paint
(equivalent to 9,000 gallons of paint)

Waste & Disposal
15,000 pounds per year of paint related wastes
(90 percent of waste is due to remaining liquid paint processes)
Waste reduction achieved (annual basis):

  • 50,000 pounds of VOC air emissions
  • 40,000 pounds of waste paint filters
  • 5,000 pounds of hazardous waste paint and solvents

Energy Use
400° F cure temperature using 2.6 million cubic feet/year of natural gas. The increase in energy use was offset by energy savings from the elimination of spray booth air flow.
Economics Capital Costs
$545,000 to purchase and install: powder paint system; environmentally controlled application room; oven upgrades; and improvements to metal preparation and cleanup.

Operation/Maintenance Costs
Total operating and maintenance costs were reduced by $87,000 per year with the new powder painting process. This figure includes savings in purchasing and disposal costs.

Payback Period
Total cost of painting has been reduced by 25 percent, on a square foot of painted surface basis, due to higher transfer efficiency achieved with the powder coat system. The payback period has been calculated as 6.3 years.
Benefits This project was approved based on predicted improvements in quality and environmental benefits. Powder painting of parts has improved corrosion resistance significantly. The surface finish quality of the parts also is superior to that achieved with the liquid painting process. Substantial reductions in VOC air emissions and paint-related wastes have been achieved. Employees have benefited from the elimination of solvent use. The powder booths and environmental room are effective in controlling dust from the process.
Obstacles The conversion of the existing conveyorized paint system to powder paint was accomplished over a holiday shutdown. Only very minor start-up problems were encountered. Employee acceptance of the powder painting process has been exceptional.

Powder coatings will not work for all substrate materials or part configurations. In addition, the high capital cost may be prohibitive for small shops. Other pollution prevention measures may need to be investigated in these situations.
Technology Transfer Miller is willing to provide tours of its facility and share its expertise on powder coating with others. An article on Miller's powder system was published in the May 1995 corporate newsletter which is distributed to over 250 of its worldwide business units.
Other Pollution Prevention Activities Miller has replaced organic solvent cold cleaners with aqueous systems for all high volume metal parts cleaning. In addition, Miller has replaced conventional solvent-based insulating varnish for electromagnetic assemblies with very low VOC resins in several applications.
Company Address Miller Electric Manufacturing Company
1635 West Spencer Street
Appleton, Wisconsin 54914
Contact Person Ken Brown, Senior Environmental Engineer
Phone: 414/735-4472
FAX: 414/735-4180
Pollution Prevention Resources Free, On-site Technical Assistance
University of Wisconsin Extension
Solid and Hazardous Waste Education Center
Milwaukee area: 414/475-2845
Remainder of state: 608/262-0385

Pollution Prevention Information Clearinghouse
Wisconsin Department of Natural Resources
Hazardous Waste Minimization Program
608/264-8852, 608/267-9523 or 608/267-3763
DNR Logo


Bureau of Cooperative Environmental Assistance
Wisconsin Department of Natural Resources
P.O. Box 7921
Madison, WI   53707
608/267-9700

PUBL-TS-055