Parts enter one of Ames’ two identical paint tanks, currently filled with orange anodic acrylic electrocoat.
The Ames True Temper plant in Harrisburg, PA, first started electrocoating its wheelbarrows, snow shovels, garden hose reels and other lawn and garden products in 1979. Using two identical 14,150-gallon e-coat tanks and post-rinse systems, Ames was able to process parts coming from a common pretreatment system through one tank or the other, depending on which color was desired. In the early days, the colors of the anodic coatings alternated among white, red, blue and black. Large storage tanks held the colors not being used in the paint tanks. A typical changeover took the better part of a day, if not longer. With these long changeover times, the idea of on-demand production was hard to imagine.
Several years ago, however, internal and external pressures drove Ames True Temper to make its paint system a more efficient and on-demand process with the ability to coat six colors - red, green, blue, black, gray and orange. Equipment upgrades such as programmable logic controllers (PLCs) and mix-proof valves, combined with vendor assistance, contributed to an automatic paint transfer process capable of switching from one color to another in a matter of minutes. This ability has allowed Ames to meet rush orders and adjust production schedules on the fly when necessary.
Design Considerations
Ames’ old transfer process required manual valve turning, manual flushing, manual rinsing and other manual adjustments that could not be trusted in a high-speed environment. Omitting just one step could result in the mixing of two or more colors - a quality control disaster, not to mention the financial impact of dealing with off-color paint. A new method was needed that could incorporate speed and reliability without sacrificing quality.The design considerations for this new method were extensive. Ames spent long hours in the design process making sure that product quality would not be affected by speeding up the paint transfer process. Specifically, color control would be important when swapping the six different colors through the various components of the paint system, such as the heat exchanger, bag filters and ultrafilters. Areas of the system that might hold excessive paint would need to be identified and addressed to avoid accidental mixing of the colors.
Ames also wanted to evaluate whether any of its existing equipment could be used in a high-speed transfer process. Parameters such as flow rates, pressures and pipe diameters had to be considered. Storage tank volumes, plumbing and venting were examined to make sure any potential splashing or foam issues would be nonexistent. The ultrafilter system was examined to see if separate membranes would be required for each color or if the existing common system would be acceptable.
Safety was also a big consideration in the initial design. Could a high-speed transfer process be implemented while ensuring that those involved in the process were safe? What types of precautions would be needed to make sure leaks and spills would not occur? What electrical hazards might be involved in the process, and what could be done to eliminate them? Should a lockout/tagout program be associated with the process, and if so, what should it entail?
Ames worked closely with its paint vendor during the initial design stages to understand what, if any, limitations the paint chemistry would present. Variables such as additional shear and higher temperatures were possible, so laboratory testing was needed to verify that these issues would not pose a problem.
Finally, the cost to make it all happen was considered. Ames worked with various equipment suppliers to determine if a high speed transfer system made economical sense, or if the company would be better off installing additional e-coat lines to handle the multiple colors.
A PLC is used to transfer the colored e-coat between work tanks and storage tanks.
Equipment Choices
Using the information obtained during the initial planning and design meetings, Ames decided that the installation of a high-speed transfer system was, in fact, the right option to pursue. With more than 20 years of electrocoat experience, and with a little help from its vendors, Ames set out to convert the design on paper into a reality.To address the company’s first concern of producing a quality product that was consistently on color, a number of mechanical changes were made to the system. The main focus was to automate the system as much as possible to eliminate the potential for cross contamination. Manual valves were replaced with state-of-the-art mix-proof valves, which allow the same line to be used to transfer all six colors to and from the paint tanks to their respective storage tanks without the risk of accidentally mixing two or more colors together.
The valves were tied into a PLC that allows the operator simply to push a button corresponding to the paint tank that needs to be emptied and cleaned. The PLC routes the paint to the proper storage tank by triggering the proper valves and starting the transfer pump. Once the transfer is complete, the operator can push another button that uses permeate from the post rinses to automatically spray down the work tank and then flush through the system’s various plumbing components. While this process occurs, the operator typically supplements the rinse process with additional deionized water from a garden sprayer to target any areas that might need additional rinsing. Upon completion of the flush, the product is automatically transferred to the holding tank that already contains its respective electrocoat bath.
Ames has six storage tank setups, one for each of its colors. Each of the setups is equipped with a circulation pump, bag filter and heat exchanger. The heat exchanger and bag filter allow Ames to control bath parameters while the paint is in storage, thereby ensuring that the paint will be ready to use immediately when transferred to the work tank.
Once the work tank has been emptied and cleaned, the operator needs to push just one more button to initiate the tank refilling process with the desired color. As filling begins, the ultrafilter pump is started, and the permeate that is generated is used to fill the post-rinse tanks.
The entire process can be accomplished in a few dozen minutes. While the conversion is occurring in one work tank, the other is still being used for production, allowing Ames to avoid downtime. This lean and on-demand production process has allowed Ames to say “no problem” instead of “no way” when confronted with challenging time constraints.
While the process seems to be streamlined, Ames is always looking for ways to improve. In the fall of 2005, a new spiral wound ultrafilter system was placed on-line, resulting in three times the permeate generation of the old tubular system. The new system cut the time for conversion from one color to another even more, as the post rinses could now be filled even faster.
The automatic control system is not Ames’ only defense against color contamination. Ames also works with its paint vendor to submit routine color chips, and its incoming paint can be tinted accordingly should some color drift occur on-line.
To make sure that the whole process was safe, Ames worked with its vendors to select the appropriate equipment for the job. A lockout/tagout program was put in place to ensure that the transfer process could not be started if someone was working on or in the storage or work tanks.
Financial Considerations
As offshore manufacturers moved into the marketplace, Ames needed to develop a market strategy that would keep the company competitive. Part of that strategy was to offer its customers unique product lines, including custom colors and delivery-on-demand. Ames spent significantly less money to completely automate its existing e-coat system and add two additional colors than it would have spent to add just one more electrocoat system of a similar size. This type of out-of-the-box thinking has allowed Ames to be competitive in today’s market and has positioned the company to remain competitive in the years to come.The Future of Multicolor Systems
What Ames has known and used for years is quickly becoming an industry trend. Many existing and potential electrocoat users looking for one-coat coverage are finding it tough to justify building an entire system for just one color. Paint vendors and system houses are responding to these concerns and are working with finishing operations to develop systems capable of multicolor output at a fraction of typical standalone system costs.For more information about e-coat, visit www.electrocoat.org.
Editor’s note: More information about Ames’ ultrafilter system can be found in the related article "Faster E-Coating with Advanced Ultrafiltration,” Finishing Today, March 2007. Not a registered user? Sign up today at www.finishingtodaymag.com/register. It’s fast and free!
