Adding an Electrocoating Line Quickly

Greene Manufacturing Co., Connersville, Indiana, saw the need for a large capacity, fast turnaround electrocoating system in its region. It also knew it had to act quickly. "We are family owned, so we can act quickly," stated Jim Hamilton, Jr., Green's president. "And, we have a group of stockholders committed to growth and customer satisfaction who are willing to take risks and try new processes. Because of those characteristics and the assistance of some first class suppliers, we are now one of the largest electrocoaters in our area that is not wholly owned by an automotive manufacturer."

One year after starting up the line, Green is a major contender in the electrocoating arena, with a line capable of processing up to $60,000 in sales an hour.

Neither the company's growth nor the success of its electrocoating line was an accident. "We are focusing on tier one automotive suppliers, just as we have in years past," noted Mr. Hamilton. "We have just broadened our services in line with our market's perceived needs."

Electrocoating has been around since the late 1950s, but is coming into play much more because it is a low-cost coating that provides excellent corrosion protection. When Greene saw this window of opportunity in its marketplace, it decided to invest in an electrocoating system.

However, the company didn't proceed without some careful thought. It wanted to be certain that it could offer a high-capacity line in a facility that had ample square footage. This would enable it to receive product in truckload quantities, stage it and run it, rather than have customers ship product in partial lots.

"We decided to continue to target customers that have large daily volumes and require quick turnaround," Mr. Hamilton pointed out. "Our objective was to initially provide a 48-hour turnaround on orders and ultimately achieve a 24-hour turnaround cycle. Yet we want to maintain our large part/small part flexibility. Many job shop operations typically look at a three-day minimum turnaround. We are striving for just-in-time capability."

Greene knew that others would quickly see the same opportunity that it had. The company felt that it had to get the new line up and running right the first time. Because electrocoating is a relatively new process for Greene, it sought the best and most advanced pretreatment and coating technologies.

"When we started the electrocoating line in 1995, we said we wanted a finishing process that would provide the best adhesion and corrosion protection in a finish that was consistent from part to part," Mr. Hamilton said. Additionally, the company sought to have exceptional ease of control in its systems to quickly accommodate a variety of jobs and maintain consistent high quality in each assignment.

After much consideration, Greene selected Bonderite 1993 pretreatment process from Henkel Surface Technologies, Madison Heights, Michigan. The process is a seven-stage internally accelerated polycrystalline zinc phosphate system, coupled with the DuPont Cormax II electrocoat process. It had demonstrated widespread success in other areas, but was relatively new to job shop operations.

The first stage is a spray-type cleaner that uses Parco® Cleaner 319. It has a multi-metal function (zinc, aluminum, galvanized) that can clean a range of soils and also prevent soils from redepositing on parts.

After a warm-water rinse, parts enter the conditioning stage. Greene uses Fixodine^® Z10, a titanium phosphate, to promote dense, small crystal morphology in the subsequent zinc phosphate bath. Greene uses a slurry tank for the powdered conditioner. This lets Greene inject fresh conditioner into the final misting halo, overcoming the tendency of the bath to age and not perform as well as possible. This assures fresh active titanium phosphate on the part surface. Greene is typically in the range of less than five microns of crystal morphology size.

After conditioning, parts are treated with a solution and rinsed with cold water. Chromium is used as a post treatment because of Greene's ability to process it through its waste treatment facility. These steps are followed by a DI water rinse before air dry-off.

"Control is simpler, too," confirmed Mr. Hamilton. "Additions are not that big and are controlled by one metering pump, quickly and precisely. We use about 30 pct less than we did in the zinc phosphate system. Desludging has become much less of a problem as well. With the new pretreatment system running for almost a year, we have only had to desludge twice, about one 55gal barrel."

Mr. Hamilton proudly points out that, "Our state-of-the-art waste treatment facility coupled with our cost-efficient pretreatment system gives us an added edge over other job shop coaters who have to contend with trucking waste material away or must use environmentally friendly chemistries."

Greene's electrocoating system has a 23,000-gal capacity. Once parts exit the drying tunnel of the pretreatment section, they go through the electrocoat process, which is followed by a three-stage post process and the cure oven. The line cycle is 24 fpm and averages approximately 72 minutes from load to unload.

"Our volume capacity is 30,000 sq ft per hour," Mr. Hamilton said. "We are presently operating at about 50 pct of that volume capacity. The line is set up to run in workcell concepts. Workers operate in teams to run each type of part and are trained in running that specific part and what to look for. In addition to this type of customer-friendly know-how, we have an opening door system that can handle parts up to 30 × 58 inches."

The bulk of Greene's business has been automotive, but electrocoating is allowing it to enter several other industries. Because it has hit virtually everyone who is a tube fabricator, its work can just as easily end up in a transmission dip stick or a piece of lawn furniture or the frame of a point-of-purchase display. Greene has even done parts for satellite dishes and underground junction boxes for fiber optic cable systems. With all of these opportunities, Green is bound to keep growing.