Keeping Your Aniloxes Healthy

Anilox rolls are at the heart of the flexographic printing process, so it only makes good business sense to try to extend the life of these critical components to protect your investments. Proper care is essential. While the flexographic process essentially is the same on every press, unique characteristics of each print job, each print shop, and each press make anilox roll care methods different for every print shop.

Each anilox roll supplier has its own recommendations for ­caring for and ultimately extending the lives of its anilox rolls, and you should always start with your supplier. But as package printers run their jobs, operators will no doubt find that nuances of their anilox rolls have helped them develop some tricks to maintain the quality of their jobs without replacing their rolls. ­packagePRINTING has compiled a few of these tricks as well as supplier recommendations, to help you manage any problems you may have have with your anilox rolls.

Start with your supplier

Your supplier can typically offer the best advice for prolonging the lives of your anilox rolls. The anilox roll manufacturers can train your operators and your trainers to correctly store, maintain, and clean your anilox rolls. “The bottom line is that most longevity issues with ceramic anilox are inadequate or incorrect care, handling, cleaning, and basic maintenance,” says Steve Wilkinson, ARC International. “It is critical, therefore, to be able to extend the life of a roll and maintain it at [its] maximum performance by first ensuring that the operators are fully trained in how to handle, clean, and maintain all types of anilox surfaces.”

David Lanska, midwest regional sales manager, Stork Cellramic, adds that “there are a lot of factors that affect longevity and performance. These can be divided into cleaning, handling/storage, and mechanical issues. Maintaining cell carrying capacity is critical to the performance of the roll, which is why so many printers spend thousands of dollars on anilox cleaning equipment.”

Speaking of cleaning, Pete ­Mulheran, president of SANI-BLAST, says his company advises its customers “to exercise good housekeeping practices and always clean their aniloxes after use with a daily cleaner. They should deep clean their aniloxes frequently and before storage...to maintain the integrity of the rolls.”

Sean Teufler, technical graphics advisor, Harper Graphic Solutions, a division of Harper Corporation of ­America recommends the anilox supplier conduct a press area audit focusing on these areas of concern:

• Does the storage protect the rolls or create another hazard?

• Can aniloxes be installed and ­removed from press and moved to storage without ncidental contact?

• Can press operators and assistants maintain the anilox surface by proper doctor blade and chamber metering?

• Examine cleaners and cleaning techniques for potential causes of anilox abuse and damage.

Echoing other suppliers, Dave ­Burgess, vice president of sales and marketing, Pamarco Global Graphics recommends several points to help prolong anilox roll life:

• Clean all anilox rolls in-press as often as possible, between color changes, etc., to ensure that ink is not allowed to dry in cells while rolls are on press.

• All rolls should be deep cleaned on a consistent, regular basis.

• All customers are encouraged to purchase roll inspection equipment so a bench line for depth and volume of engravings can be established. Then all rolls should be checked after cleaning to ensure that rolls are back as close to possible to original specifications and that adequate records are kept to ensure accuracy.

• An annual audit should be conducted of all rolls in customer inventory, preferably by the roll supplier, to obtain a “camera shot” in time of the inventory and to highlight any anilox rolls that need either cleaning or replacement due to cell wear or mechanical damage.

Tricks of the trade

Package printers can follow supplier recommendations to the letter, but there are nuances in any print shop—nuances that create very specific situations requiring creativity and ingenuity to overcome.

For example, Shane Vaughn, KDV Label, Co., Inc. (Waukesha, Wis.) says KDV “takes a ‘pit crew’ type of philosophy when making changeovers. We take our aniloxes out of the press and make sure they get cleaned between each color change. Very rarely do we do ‘pour overs.’” About every six months, KDV will sonic-clean the anilox rolls.

“A thorough washup is important,” says Colin Shannon, plant operations, Artcraft Label. “Flush the inking system a few times making sure all ink residue is gone. An anilox roll cleaner is a definite asset to any printing company. We have a plastic media blasting unit which has helped achieve consistent color quality over and over.”

Rich Rosenberger, corporate printing manager (flexography), Solo Cup Company, says the company runs a high alkaline solution through the chambers while engaged to the anilox roll when a deck is not in use. “This thoroughly cleans not only the cells, but also the entire inking system,” he explains. “We also change the magnets and filters at this time.” Solo Cup uses either sodium bicarbonate blasting chambers, which can reach down into the cells and basically sandblast the dried acrylics, or it uses sonic baths, which basically send high-frequency waves through a high-alkaline solution, vibrating dry acrylics out of the cells. Operators also use handheld brushes, which serve to move a high-alkaline solution over and into the cells, so it is a thorough rinsing with the brush and absorbent rags that are instrumental when the roll is in the press.

He explains that press operators sometimes get into the habit of ­trying to clean rolls with a solution that is too low in alkaline, which works against them because low pH will harden the acrylics right into anilox cells. “Cleaning an anilox roll with nothing but water is a big mistake and will serve to harden the ink into the cell within minutes of placing even a brand new roll in press,” he says. “Water can actually be acidic with a pH of 6.”

Proper maintenance

Shannon cites the following as regular maintenance items: “Check all bearings and gears on a regular basis and replace when worn. If the anilox doesn’t run true, you will get uneven wear causing inconsistent color from one side to the other. Improper doctor blade settings will cause the same kind of damage.”

Scoring is another problem ­Rosenberger says stems from no filters, broken filters, no magnets, filled magnets, foreign particles in the ink, or worn blades. “If you are scoring the anilox,” he says, “you are doing it with something harder than ceramic, which has a pretty good Rockwell hardness relative to the substances an anilox comes in contact with during its use.” (For more on doctor blades and scoring, turn to page 34 for ­packagePRINTING’s doctoring ­system coverage.)

Moving forward

According to Shannon, advancements in anilox technology during the last 20 years have been “amazing.” “Laser engraving [has] made it possible for the flexo printer to print the quality of labels needed to compete in the litho market,” he says.

Vaughn echoes Shannon’s appraisal of laser engraving. “The laser-engraved aniloxes have continued to help [with regard] to keeping up with having solid coverage and still being able to print screen work,” he says. “However, I believe [it is the] combination with digital plates [that] makes the best print job.”

“There is one roll that seems to have a cut, called a diamond cut, that actually does have better release than other rolls,” adds Rosenberger.

As you move forward, do not only pay attention to anilox technology, but also the service you’ll get from your suppliers. “Some anilox roll companies research and invent new ways to engrave ceramic, going as far as desiging their own laser engravers and new techniques of engraving,” he explains. “These are the anilox roll suppliers that you want to align yourself with.” pP

Don’t Forget the Ink System

A mistake some press rooms make is failing to get all of the solvent out of the entire ink system before a new ink is introduced. This causes the press operator to think that the anilox is not running the correct volume. What’s actually happened is the operator has added a quart of water or high alkaline to the ink set.

This occurs when the press operator cleans the ink system with a bucket or two of solution, picks the pump up out of the solution, allows the solution to drain for a bit, and then drops the pump into the next color. Even when going from red to red or green to black there is still quite a bit of solution in the filter and the hoses which works to weaken the ink and create the false impression that the anilox volume is not what is advertised.

When an anilox is not running the proper volume, the first idea is to “tone the ink” by adding base. There has always been the challenge of matching the hand proofer in the ink room to the anilox in press.

Typically, the ink specialist will mix the ink stronger in the ink room so that when it goes to press he has a good chance of adding only extender and not base to the mixture to get it right. This procedure is fairly common in flexography, but in an age where uptime is everything, this procedure is old school and unacceptable.

The ink room must find a hand proofer that matches the anilox, and the anilox must remain clean with a volume conducive to the graphic expectations.

In fact, when the ink coming out of the ink room is a delta 1.5 and the pressroom achieves a delta 3.0 or better out of the kit, the next step is to duplicate that a thousand times and you will find a reduction in your ink consumption. It can be done, we do it.

—Richard Rosenberger, corporate printing manager (flexography), Solo Cup Company