Special Coating System Keeps John Deere's Gator^® Utility Vehicles Looking Good Under the Toughest Conditions

By Gregg Bocchi
Executive Director
The Powder Coating Institute

Best known for their use on farms and golf courses, John Deere's Gator^® off-road utility vehicles, which can travel up to 18 miles per hour, were enlisted for more patriotic duties following the attacks on the United States on September 11.

Manufactured at the new John Deere Vehicle Group facility in Williamsburg, VA, 44 Gators were sent to New York City to assist workers at the World Trade Center site in lower Manhattan. The company also sent ten Gators to help in the rescue and recovery effort at the Pentagon outside Washington, DC.

As work continues at these sites, and Gators haul away debris and transport workers, these special vehicles will continue to look good on the outside thanks to a state-of-the-art powder coating system installed during the summer of 2001 at the company's new 300,000-square-foot Williamsburg facility.

John Deere, which has been manufacturing Gator utility vehicles for nearly a decade, was no stranger to powder coating, having used the environmentally compliant technology on Gators and other heavy equipment in its extensive line. Last June, the company entered a new era by opening a dedicated 32,000 square foot coating operation and using a combination of products that further enhances the Gator's finish.

A new electrodeposition coating, or E-coat, is now used as the primer on all Gators. This technology, when combined with powder coating, provides benefits not only to John Deere, but to its customers and the environment as well.

John Deere sought a turnkey supplier when it came to creating a fully automated coating system. A systems house was brought into the facility when it was no more than a roof and dirt floor.

A key design element in the efficiency of the whole operation is the power and free conveyor, with over three miles of conveyor track winding through the building. Components unload from the trucks and go right onto the assembly line, proceeding to individual cells in the plant for welding, pretreatment, coating, and assembly, and are crated and shipped right from the assembly line, with no warehousing.

In full operation, any point in the conveyor rarely proceeds empty, with loading stations only a matter of several feet from the last unloading station. Some areas of the plant have workers on double duty, hanging or removing parts from two different conveyor tracks, only needing to take a few steps back and forth between each track.

John Deere relied on its in-house experts to select the coatings and chemicals for the plant. Andrew Guziewicz was hired to install and operate the finishing system, and aided by the flexibility of a power and free conveyor system, attests to the operation's ability to coat "any model, any color, any sequence, any time."

First, the parts move through a nine-stage pretreatment process, including a spray and immersion degreaser, full immersion rinse, zinc phosphate-base protective layer, and a chrome sealant, followed by water rinses.

The parts then receive an epoxy electrocoat primer at a thickness of one mil, then proceed to the overhead curing ovens, before entering a climate-controlled powder room which is maintained at a temperature of 75°F and 50% humidity. The powder room has three semi-automated booths and one manual spray-to-waste booth, using virgin and reclaimed powder, applied at a thickness of three mils. Manual touch-up, if necessary, can be conducted at each booth.

Next, the parts are cured in a gas-fired oven at 385°F for 50 minutes and then proceed to a cool-down area. The finished parts are raised to a stacking area above the production floor to maximize the area available for plant operations.

The E-coat and TGIC polyester powder finish used on the Gators offer superior corrosion and chip resistance, key issues for these vehicles, which are used in a wide range of harsh climatic situations.

"Gator utility vehicles are exposed to many different conditions ranging from cold temperatures in the north, to salty beaches and hot weather, to fertilizer on golf courses," said Lou Gomez, manager, manufacturing engineering, John Deere Vehicle Group. In addition, a special Gator, dubbed M-Gator^®, is used by the U.S. military.

With this special powder coating and E-coat combination, John Deere Gators have an "automotive quality" finish, said Guziewicz. Colors include well-known "John Deere green," "work site yellow," "olive drab," and black.

Another bonus is excellent UV protection, which means Gator utility vehicles will retain that "just-off-the-line" appearance for a longer time.

The line has had no serious quality control issues. The automated control system has working parameters checking temperature and chemical balance of the finishing line. Periodic checks for film thickness are also conducted on the line, and there are tests for adhesion, elongation and weathering. The parts also meet 1000 hours of salt spray corrosion resistance testing.

The benefits don't end there. The new coating system is free of hazardous air pollutants (HAPs) and is extremely low in volatile organic compounds (VOCs), which helps John Deere in its quest to be an environmentally responsible manufacturer.

Since they are only burning natural gas, air waste is minimal. There is an in-house waste water treatment for the entire system, and the liquid waste is water-based and meets all environmental regulations before being returned to city drains. The non-hazardous zinc sludge, following proper treatment by a licensed waste disposal contractor, is disposed of in a landfill.

"We worked very hard and were successful in exceeding all environmental requirements," said Gomez. "This is vital, since we are located near the Chesapeake Bay."

John Deere is confident that building this new dedicated coating shop was a sound choice.

"The process is friendly for the environment and makes good business sense for these utility vehicles," says Gomez. The company also knows that the special combination E-coat/powder coat system will keep Gators looking good for all its customers, including those working on America's recovery and the war on terrorism in Afghanistan.

# # #