Splish Splash, I was Takin' a Bath ...

Converters will be singing once they've mastered keeping their anilox rolls clean with these supplier cleaning tips!

By Joy English

Assistant Editor

IT'S BATH TIME! And a mother's famous words, "Don't forget to scrub behind your ears," are ringing loud and clear. Bath time, to a child anyway, is never much fun. But, it is necessary—and for anilox rolls, it is essential.

For anilox rolls, scrubbing the hard-to-reach areas is key to removing dried ink. And just using water will not get the job done. A cleaning system must be used. Several suppliers have given packagePRINTING their top anilox roll cleaning tips, while several converters have provided feedback on the benefits achieved from the cleaning systems they use.

Rub-a-dub-dub

"The anilox roll is arguably the most critical component of the flexo process, in terms of ensuring print quality and standardization," says Jack Mikolajczyk, vice president of solutions, Pamarco Global Graphics. "By optimizing the performance of the anilox, the printer can consistently control color density and strength. This reduces set-up time and press downtime, and ultimately reduces waste and improves productivity."

Yet, if the rolls become clogged with ink or coated with additives from the ink, converters will have a multitude of problems on their hands, from reduced ink capacity to low color density and poor quality. The life of the anilox roll will also decrease.

With all of these outcomes riding on clean rolls, one would assume that converters would make cleaning their anilox rolls a top priority. But, according to Jan Bendixen, president of Flexo Wash, many do not. "I have had experiences with production managers and converters not understanding that anilox rolls need to be cleaned."

Dirty to dirtiest

Anyone who plays in the mud all day long is going to end up dirty. Anilox rolls play in a similar environment—covered in ink and/or adhesives, in ambient air that can be entrained with dust and fibers.

Mark Hahn, VP sales and marketing, AAA Press International, says, "Anilox rolls (particularly ceramic) need to be cleaned because any engraved anilox roll will not release all of the ink inside its cells, primarily due to the shape and size of them. The ink left in the cell will eventually dry (or cure, if UV), reducing the effective volume of the ink-carrying capacity of each cell."

Plugged cells cause inconsistent ink volumes. Jim Heffer, president of Anilox Roll Cleaning Systems, says, "Inconsistent cell volumes cause a myriad of problems, which include an inability to achieve quality color matching from run to run." When this occurs, converters must compensate with additional efforts to achieve an acceptable color match.

In addition to plugged cells, anilox rolls may also lose their wettability due to a build-up of additives that are in the ink. Lloyd Dreger, technical director at Laserlife, explains that additives, such as polyethylene waxes, silicones, and Teflon suspensions, are added to inks in order to improve gloss, mar resistance, and other properties. "But when these particles become embedded into a print cell surface, that part of the surface becomes hydrophobic (water-hating) and thus won't attract anymore ink to it." The ink will begin to bead up on the surface and print quality will become blotchy.

Continual cleaning, though, will minimize these print problems, while extending the life of the anilox roll. According to Bobby Furr, technical sales manager, HarperScientific, "With the proper cleaning procedures and maintenance of anilox rolls, a roll will last at least five years."

Squeaky clean

It's very clear—for the best results, anilox rolls should be cleaned after each run. "Most converters that have instituted cleaning programs have found that if the anilox is deep cleaned immediately after it comes out of the press and before returning to the storage rack, it will be capable of delivering the full ink volume it was designed for," says Bob Temple, president/owner, Absolutely Micro*Clean. But before a converter begins cleaning, it is important to determine a cleaning approach.

Mikolajczyk recommends all converters take a proactive approach. "Don't let the roll get dirty and then clean it—keep it clean all along." He suggests starting early, by maintaining the cleanliness of the anilox rolls right from the beginning. "In the long run, starting early and keeping the rolls clean will lead to less printing problems and roll changes."

Marty Cansler, national sales manager, pressroom products, Max Daetwyler Corp., agreed, saying, "Clean often! Don't wait until the roll is on the press to find out it needs to be cleaned." By only cleaning when there is a density problem, converters will have excessive waste and downtime, says Cansler.

During the cleaning process, inspection is also key to the quality and life of the anilox roll. Furr recommends that converters "use a magnifying light scope on mechanically engraved rolls and a 100x or higher scope on laser rolls to visually check if the anilox rolls are clean."

Temple, agrees, "This is an incredibly valuable tool because it can let converters look into an individual cell. They can then take an accurate depth measurement by using a digital gauge."

Wear is another factor that can be monitored, says Temple. "Over time, as the walls wear down, the cells will hold less and less volume of ink, and will lose density on press. With a good scope, converters can easily see when this happens and be able to tell when to send the roll out to be recoated."

When it comes to selecting a cleaning system for their anilox rolls, converters have numerous options, from baking soda blasting, ultrasonic, and plastic media systems to cleaning solutions and brass or stainless steel brushes. Yet, whichever system they select, Bill Poulson, N.E. technical advisor for Harper GraphicSolutions, advises that all converters make sure that the chemistry of the cleaner is compatible with the ink used, and follow all manufacturers guidelines for the cleaning process.

Communication between the supplier and the converter is also important. Furr comments that HarperScientific developed the "Anilox Protection Program" to help converters determine the best cleaning methods for use with Harper's anilox rolls, including optimal cleaning times based on line screen counts.

Word of mouth

One of the best ways to select a cleaning system is to hear feedback from other converters who have purchased and used the system.

When looking for a system that will not damage the rolls, Dean Squires, plant manager for Roplast Industries, recommends Absolutely Micro*Clean's anilox roll cleaning system. It uses a special plastic media that is "engineered for the process to ensure thorough cleaning without exposing the anilox to potential damage," says Temple.

Squires says, "The system is great, and very time-saving." Roplast runs water-based inks, which require a catalyst to help the inks perform. This catalyst clogs the anilox rolls. "With the old system we were using, we would have about three hours of downtime. Now, we only have about 35 minutes of it," says Squires.

Rick Sexauer, printing project engineer for Georgia-Pacific Corp., Dixie Engineering, uses the Flexo Wash 3000, a cleaning system for wide-web press anilox rolls. According to Bendixen, the system first sprays the rolls with a solution that is diluted in 50 percent water and heated to 130°F. After 15 minutes, the system then sprays the rolls with 100°F water at 1,500 psi.

The system can also be used to clean plates. This dual ability attracted Sexauer to the product. "[I selected it because of] its ability to clean high line screen anilox rolls without the possibility of plugging, and its capability to wash plates as well as anilox rolls," he says.

Vanguard Plastics Production Manager Dan Hillard has been impressed by HarperScientific's Ceramclean II. "It's the best paste-type cleaner I have found, and it's best for cleaning while the anilox rolls are still in the press. I'm not required to remove them in order to clean them."

Both environmentally and operator friendly, Hillard says, CeramClean II "has allowed me to run better print quality and to have better uptime because I can clean my anilox rolls with it in-press." For Hillard's 80˝ wide-web presses, it only takes him about 30 minutes to clean.

For outside service, Laserlife offers excellent cleaning service, according to Rich Harris, plant manager and a Laserlife customer. "They do an outstanding job. I send my anilox rolls to them and they get them thoroughly cleaned." Unlike some converters, Harris says that he doesn't run inks, but adhesives. "I had been using the baking soda blasting method before, but that didn't work as well as I needed. Now, I am using Laserlife's laser cleaning, and it is phenomenal."

And if baking soda blasting is a converter's preference, Zalman Zohar, printing manager for Ultra Flex Packaging Corp., uses Anilox Roll Cleaning Systems' Sani Blast anilox cleaning system, and says, "The system has improved my print quality and consistency. We know what the volume should be before I clean and I know that when it is cleaned, it will give us the same consistency."