Automated Powder Coat Line at MTE Improves Finish Quality, Efficiency
Sep 1, 1998 12:00 PM
PRODUCTIVITY GAINS usually come in little packages, the result of doing a lot of things slightly more efficiently than before. Opportunities to triple productivity in one big step don't come along very often.
But Monroe Truck Equipment (MTE) recently installed an automated powder coat line that performs in one shift the work that the company previously did in three. And MTE did so as part of the production process that frequently is a bottleneck for manufacturers.
The company uses its new conveyorized line to apply a durable finish to its snowplows and hopper spreaders in addition to custom truck bodies that operate in corrosive environments.
"Until the powder coat line opened, we were painting with three shifts a day, five days per week," says Rick Rufenacht, vice-president of marketing and sales. "With the automated system, we can meet our needs in one eight-hour shift. We can use it to powder coat our manufactured products-stake racks, fabricated brackets, and our snow and ice equipment. The powder coat equipment is big enough to handle a V-box spreader."
MTE built a 63,000-sq-ft addition to its facility in Monroe, Wisconsin, to accommodate the line. The process, with a conveyor that transports fabricated pieces throughout the system, removes much of the labor. Once the components are hung onto the conveyor, they do not need to be touched until after they are coated. The only human involvement, outside of the loading and unloading of the conveyor, is the application of the powder.
Multi-Step Process The line is the result of a team effort by external engineering consultants, MTE engineers, company shop personnel, and Dick Feller, founder of MTE.
Components go through several steps as they ride the conveyor through the powder coat line at a speed of 3.5 feet per minute. First they are shot blasted to remove surface impurities that otherwise would reduce the bond of the coating to the metal.
With the surface cleaned, the line moves to a five-stage wash system for deeper cleaning. These steps include an alkaline wash, clear-water rinse, application of iron phosphate, another clear-water rinse, and a sealer that prevents flash rusting.
A drying oven, with air heated to 100 degrees F, enables equipment to move more quickly through the process. Heating the steel also makes the coating more uniform.
The coating is applied to a thickness in excess of three mils. MTE personnel use electrostatic guns to coat the product. The electrostatic process reduces overspray, and the design of the booth captures 98% of the powder so that it can be recycled. Furthermore, the powder-coating process emits no volatile organic compounds into the atmosphere.
The coated piece is then baked for 25 minutes at temperatures ranging from 150 degrees to 600 degrees F, depending upon the thickness of the steel being coated. The normal curing temperature is just over 400 degrees F.
Major Market Snow and ice control equipment has been a major market for the 40-year-old company. After distributing snowplows, spreaders, and other lines for other manufacturers, MTE began offering its own products in 1983.
The first was a tailgate spreader, followed by an underbody scraper two years later. The success of these products, combined with financial problems of several companies that had been supplying MTE with equipment, led the company in 1990 to form a separate division for snow and ice control equipment.
Initially the division's purpose was to serve the six-state area surrounding Monroe. But the scope has expanded significantly since then. The company now sells its products through a network of 78 distributors. A staff of five field sales representatives calls on distributors in the United States and Canada. U S distributors are located throughout the Snow Belt, including Alaska and Canada.
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