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issue: September 2005 APPLIANCE Magazine

Finishing
Chasing Rainbows


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by Lincoln Brunner, Contributing Editor

Finishing suppliers are developing innovative technologies that are applying more colors, more efficiently to today’s design-rich appliances.

The Vestagon EP BF 9030 and EP RC 8020 from Degussa offer powder coating formulators the opportunity to formulate high-performance polyurethane/allophanate powder coatings at curing temperatures under 130°C. According to Degussa, the Vestagon line was developed to address the rising costs of fuel, which have forced the powder market to look for high-performance powder coatings that can be cured in less time and at lower temperatures, saving heating and cooling costs and speeding up production lines. The company also believes low-temperature cure powder technology will open the door to the powder coating of plastic, wood, and preassembled parts with excellent appearance and performance properties. Vestagon products are most commonly used to coat washing machine interiors.

For the last several years, stainless steel has dominated the appliance world, driving design trends and challenging the very meaning of “white goods.” Now, a wave of color has washed over the whole scene, taking the industry to a whole new level of design. In an informal survey, the Porcelain Enamel Institute (PEI) found that almost 40 percent of products exhibited at this year’s K/BIS Expo in Las Vegas, NV, U.S. displayed color, including biscuit and black. U.S. appliance brand Kenmore recently introduced hues such as Pacific Blue, Champagne, and Sedona (burnt orange) to its washer and dryer line. Colorado, U.S.-based Big Chill offers eight-piece retrofit kits that reface other OEMs’ refrigerators in bold throwback hues such as pink lemonade and buttercup yellow. Even stainless-stalwart Viking has added a bright burgundy and other colors to its refrigerator color options.

That rainbow effect has pushed finishing equipment and material vendors, particularly within the powder-coating segment, to a new focus on color delivery. The result is an influx of new equipment and technologies that cater to clean and efficient color changes all day long.

Nordson customers are changing colors anywhere from 20 to 120 times per shift. The company’s latest reclaiming and spray-to-waste systems have been designed to accommodate the new push toward rapid, frequent color change.

Fast Delivery Drives Changes

“Quick color change is a major driver in most everybody’s products right now,” notes Phil Flasher, lab manager for ITW Gema in Indianapolis, IN, U.S. To keep in step with demands for quick color-change, ITW Gema has developed a sandwich-wall design on its booths that promotes powder release for quick blow-down by keeping metallic objects away from the interior walls.

The company also has equipped its powder coating booths with a dense phase powder conveyor. Instead of relying on a Venturi-effect system to move powder to the gun feed hopper from the Cyclone separator, the dense phase conveyor uses a cylinder to push intermittent packets of powder back through the system with little air pressure.

The system is said to be easy to clean and purge, which facilitates quick powder change, as does the company’s recently introduced powder hose that promotes material release and eliminates hose swapping. The hose also reportedly eliminates the need to run foam cubes through them for deep cleaning and no longer requires manufacturers to dedicate one set of hoses for light colors and another for dark.

Just-in-time (JIT) manufacturing and mass-customization are also driving demand for quick-change products such as spray guns that can change colors in less than 20 sec. Both are domestic strategies to battle overseas competition. But while Chinese manufacturers almost always produce goods for less money than their U.S. counterparts, “you can’t change colors on the boat,” according to Mr. Flasher. To compete, one ITW Gema customer is changing colors as frequently as once per unit, spraying one red and the next one blue. “[U.S. manufacturers] are building to order,” Mr. Flasher says. “They get the order, and hopefully in 24 hours, they’re shipping that product. Manufacturers keep their competitive edge by being able to change on the fly.”

Also catering to quick-change trend is Deimco, a Tama, IA, U.S.-based paint booth manufacturer. Within the past year, the company has developed a manifold system for powder delivery to accompany its fast color-change powder guns. Operators of Deimco’s system can program color changes on a programmable logic controller (PLC) or choose them manually. Much like a liquid paint system would, the powder manifold purges old material and performs an air scrub before new powder is loaded.

The company originally developed the manifold system for a fireplace manufacturer, but knew the technology could serve other applications. “I think there are some other areas that it could be utilized if people knew it was available,” notes Mary Cooley, sales manager.

Deimco is also helping manufacturers speed production by offering systems with more cells, where parts are moved from station to station within a small footprint to save labor and time. Though its powder business has been down, the supplier says it has been manufacturing more cell-type systems as of late to meet the demands of lean manufacturing. The company offers two types of cells, the Powder Cell and Overhead Cell. Both are fully automatic and provide individual gun control. The main difference, as the name implies, is the overhead conveyor system in the latter. “What’s driving it is the lean manufacturing processes, where you want individual work cells and to be able to coat product right there without having pats transport clear across the plant,” Ms. Cooley says.

Of course, frequent powder color changes often means operating a complex coating line. According to Tim Klopfenstein, marketing manager for Lima, OH, U.S.-based MetoKote, the market is starting to demand highly flexible systems that can change colors with great frequency and that are flexible enough to absorb increased volumes at a future date.

One way companies keep up with demand is to outsource finishing operations, while others find ways to keep processes internal. Another option is to do a combination of both, which MetoKote says many of its customers prefer. The supplier not only designs, builds, and installs
e-coat, powder, and liquid coating equipment, it often operates the machinery so that manufacturers whose core competency isn’t surface finishing can have a line run in-house by a partner that specializes in the operation. “They look at us as another department within their organization,” notes Mr. Klopfenstein.

As part of its services, MetoKote offers inline removal of the oxides deposited on metal by thermal cutting processes such as laser. It can also install and operate single coate-coat systems that apply high-performing and UV-resistant acrylic e-coat technology as a topcoat. Another option the company offers is the use of two-coat e-coat lines that deliver epoxy primers and decorative acrylic topcoats that are UV-resistant—all of which can be done in-house.

Finishing operations that want to remain competitive must be innovative with their technology, notes Mr. Flasher of ITW Gema. For instance, in finishing the same component, a black powder coat may require 1.5 mils to finish properly while a yellow coating may require 3 mils. Control systems such as ITW Gema’s microprocessor-based Opti-tronic can store up to 255 recipes and give operators the precise air circuit controls and repeatability they need to complete those different jobs quickly and well. “It’s all about repetition and being able to come back to those settings,” Mr. Flasher says.

The days of operators cranking up gun outputs to accommodate everything and just letting it fly are gone, he adds. “For most of the powder market to remain competitive, they need quick color change reclaim systems,” Mr. Flasher says. “There are few high-volume users that can remain competitive spraying to waste.”

John Binder, marketing manager for Westlake, OH, U.S.-based Nordson’s Powder Business Group, calls the recent shift back toward a broader color pallet “an absolute fact.” He adds: “More colors mean more color changes, and customers want to do that in the least amount of time possible, because downtime costs money.”

Nordson’s ColorMax powder spray booth is a cyclone-based system that saves users from having to pull the color module in and out for color changes, a process that typically takes 45 min to an hour. For the ColorMax system, which caters to customers that recover their powder, changes usually take 7 to 10 min, Mr. Binder says.

However, that’s for companies operating at about 25 color changes per shift. Nordson also has customers making 80 to 120 changes per shift and measuring their color changes in seconds. For those customers, the supplier has developed a manual color-change system that switches powders at the push of a button. The company is working on developing that level of quick-change capability for its automatic powder guns.

“We’re still looking at that,” confirms Mr. Binder. “In order to convert more liquid systems to powder, we’ve got to get color change times down to that of liquid systems. You’ve got to be able to accommodate more colors. That has a direct implication on the appliance industry.”

ITW Gema recently developed a new OptiGun that delivers porcelain enamel spray in a flat pattern as opposed to the traditional conical pattern. The new system allows the material to decelerate in the gun, thereby allowing the frit particles the proper time to charge, but then sprays it in a more defined pattern that allows better penetration. According to the company, this feature could come in handy for appliance applications such as range tops that require porcelain enamel to be applied in numerous recessed areas that are difficult to coat.

Material Innovations

Aesthetics have leapt to the front burner for the industry’s coating vendors as well. Cullen Hackler, executive director of Norcross, GA, U.S.-based Porcelain Enamel Institute (PEI), says that while stainless still predominates most new appliance designs, color is quickly gaining popularity.

“It’s not a surprise,” Mr. Hackler says. “Our industry is responding to that. We’re not just offering the plain-old vanilla colors. There’s been a lot of development work in metallics…that look like metals or contain what look like metal flakes. I anticipate more color being used.”

Coating supplier PPG Industries, Inc. agrees and has been investing its time and efforts in metallics. The Pittsburgh, PA, U.S.-based company is focusing much of its R&D efforts on improving and varying the aesthetic qualities of its powders. “It’s hard for appliance manufacturers to differentiate in their marketplace,” notes Greg DeCamp, PPG’s general manager of Global Powder Coatings. “Research-wise, we have some interesting effects and products that we think will allow our end-users to differentiate their product and make more of a profit in their marketplace using aesthetics.”

Part of PPG’s strategy lies in searching for ways to apply a metallic finish evenly, possibly without impregnating the material with actual metal. PPG also is looking at mica-like finishes and other textured surfaces that can be sprayed on. “Our work is to pull together some different ways to go about doing that from a powder standpoint,” Mr. DeCamp says.

The growing interest in metallic finishes for kitchen appliances has not been lost on worldwide coatings giant Akzo Nobel. The company has made significant investments in trying to manufacture metallic coatings, says Andrew Cockcroft, global market segment manager for Appliance at Akzo Nobel’s UK office. “Metallic coatings offer ways to differentiate,” Mr. Cockcroft says.

In the past, metallics generally have required topcoats, but Mr. Cockcroft says Akzo Nobel is working on ways to beat that. “If you’re looking for innovation, you need to be looking for ways to move away from using clear top coats,” he says.

In addition, the drive to speed up powder coating operations while reducing costs has steered the materials side of the business to develop powdered paints that maintain a quality appearance at lower applied film thicknesses. “Certainly appliance manufacturers are looking at any way they can to reduce costs,” Mr. Cockcroft says. “[This way] you can apply more evenly, and you can apply less of it and actually get a better finish. So you win on two scores.”

Henkel Surface Technologies has kept productivity, as well as environmental concerns at the forefront in developing its 900 series of Autophoretic Coating Chemicals (ACC). The epoxy resin-based coatings, introduced earlier this year, are applied by an auto-deposition process that cleans ferrous substrates, eliminating precoating processes such as phosphating. The coatings are water-based, use no heavy metals, and do not require a charge to adhere to metal surfaces. They also deliver a high-gloss appearance that is similar to e-coat.

The ACC 900 coatings are mainly being applied as bottom coats for automotive applications, but are also being used for refrigerator condenser coils and electric motors, according to Dr. Oscar Roberto, product line manager for Autophoretic coatings in Madison Heights, MI, U.S. “We have full approvals with the automotive OEM market, and we’re working across industries,” he says.

Pemco Corporation R&D Lab Manager Scott Levy notes that customers trying to improve their efficiencies are looking for porcelain materials, particularly in powder form, that apply with more consistency than in the past. The Baltimore, MD, U.S.-based company’s customers are increasing production rates and line speeds while still requiring the same, if not better, approval rates. Accordingly, those companies are demanding powders that transfer with less overspray, better film build-up, and better color uniformity at lesser thicknesses. “Everyone is trying to get leaner and leaner,” Mr. Levy says.

Material savings means controlling particle size as well. Akzo Nobel has been working to improve its particle management technology—controlling the mix of fine and coarse particles to achieve optimum cure, flow, and appearance. For instance, to achieve better flow and appearance of a certain powder, a finishing operation may want to reduce the top-end size of the particles from 100 or 105 microns to 80 or 90 microns. The result for certain applications can be lower applied material costs and better aesthetics. Part of the theory is that by controlling powder particle size, users can tailor the size distribution of powder particles to a particular component or material.

“At the end of the day, the customer receives benefits in terms of the way the powder is applied,” Mr. Cockcroft said. “If you link those changes with technological changes in the charge characteristics of powder, then you can bring further benefits to applied coatings.”
Powder coatings aren’t alone in the color parade. Mr. Levy of Pemco says his company and its competitors in the porcelain enamel market have experimented with establishing their own looks and color schemes as well.
Even so, Pemco’s efforts lately have revolved around performance—creating a functional porcelain enamel “that actually does something,” as Mr. Levy says. Working within tried-and-true sol-gel technology, the company has recently been developing enamels with hydrophobic and oleophobic properties that make the products they coat release baked-on food more easily. The company is also developing alkali-resistant enamels that stand up under harsh detergents so items such as oven broiler pans can be run through dishwashers.

According to Mr. Levy, porcelain has always had a reputation for durability. Now the trick is to find properties to complement that. “We’re sticking with the basic chemistry of porcelain and trying to find more useful coatings,” he explains. “We’re trying to meld old technology and new technology and have something more interesting for consumers. Porcelain hasn’t had a big breakthrough in a while. We want to get people interested in them again.”

Mr. Hackler of PEI notes that one recent study that pegged the cost of porcelain enamel only slightly higher per square foot than wet paint. “The cost of porcelain enamel on a square-foot basis has gone down,” he says. “To me, that’s the biggest news out there—how the coating is competitive with all the stuff that’s out there.”

With the growing number of finishing material and equipment options available, perhaps the best advice for appliance manufacturers is consistent dialogue with its vendors. “Powder companies have to move away from just being a paint supplier or just supplying a powder coating,” notes Mr. Cockcroft of Akzo Nobel. “You have to become more a part of the finished product and understanding the true market needs of the appliance manufacturer. Finding those bridges and connections is very important.”

 

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