Fowler Associates Labs

New System Keeps Static Buildup Under Control

paraphrased by Melissa Lovin

At Avery Dennison's Lowell, IN facility operating a press is at times likened to sticking your hand in the mouth of a growling dog. These operators are put in this position as they attempt to determine the level of static buildup on a moving web press. It is only by contact with the actual substrate that they become aware of the problem, and then it is too late. As a result of this, Avery Dennison, along with other leading manufacturers in this field, have tried for years to control the static on its converting lines.

But where Avery differs from the others is that they have found something that works: the Virtual AC Intelligent Static Neutralizer from Ion Systems. This system was presented to Avery by Ion Systems as a new device utilizing technology and design previously unavailable to the converting market.

Avery has been in the process of searching for static control for several years, which was when they assigned senior process engineer, David Shanks to the task of securing the most viable static solution in an attempt to improve employee safety and optimize quality control within the company's graphics division.

According to Shanks, "Static charges can cross the line between 'nuisance' and 'hazardous'" as a common result of static buildup on many converting lines. "The charges that we were generating weren't hazardous, but they could be uncomfortable," Shanks says.

Avery's first priority has been employee safety, but this was still no small undertaking with nearly 16,000 employees and multiple facilities worldwide. In Lowell, where Shanks works, they produce a broad range of products for traditional printing technologies, as well as wide and narrow format digital printing. The products produced there are used in a wide range of applications, from short-term promotional graphics--signs, banners, exhibits, displays, and bus wrap markings--to long-term durable graphics including fleet markings, backlit signs, and vehicle striping.

Because static buildup was not uncommon on the webs and rolls, operators at Avery were experiencing static charges while working on various parts of the line, Don Hoffman, process engineering manager, explains. His responsibilities include process development, facility upgrades, and optimization, in addition to identification and evaluation of new process or control technologies.

Hoffman also points out that not only does the static on the line pose potential safety hazards to the operators, it also attracts dirt and dust which violates Avery's stringent quality standards.

Shank's teem tested a wide variety of devices to control static electricity on the web and rolls. They found that conventional static control bars on the rewinders were unable to properly neutralize material as it wound onto the rewind core.

They found that static string and tinsel worked but were not feasible options because they could either get caught in splices or, in the case of the tinsel, possibly scratch the web. Additionally, non of the products were able to communicate their operating state to the line operators.

Shanks was beginning to think of his new task as mission impossible until he heard that Ion Systems was conducting field trials for a new static control system.

The Virtual AC Intelligent Static Neutralizer reportedly had the ability to monitor and display vital operating information as well as provide stronger ionization at greater distances from the web than any other product on the market. When Shanks was given the opportunity to test the product at no cost, he jumped at the chance. He worked closely with Dwayne Hernandez, a rewinder operator who works with equipment that has been rebuilt in-house.

Positioned on the rewinder, the bar was installed to neutralize winding rolls of coated and interleavened stock film. The Virtual AC bar could be positioned two feet from the core, unlike traditional methods of static control. According to Shanks, this easily accommodates the changing roll diameters. Even line operators who have experienced first hand the lack of effectiveness of past static control methods, were pleasantly surprised with Virtual AC's ability to neutralize that static charge at such a long range.

Shanks explains that traditionally, static reducers were unable to eliminate excess static more than a few inches away from the web. Due to the natural increase and decrease in web diameters during the course of converting or rewinding, the company requires a source of static control that could operate a few feet rather than inches away from the web.

Shanks knew he had a winner when Dwayne Hernandez tested the equipment. "Basically, Dwayne wouldn't let me take it away to try on another part of the line," Shanks laughs. "We knew the system worked when it passed the 'Dwayne test'." Since then Avery has ordered two additional units for use on rewinders.

The Virtual AC equipment not only eliminates the static buildup, it also notifies operating personnel when system itself needs cleaning--another major concern in eliminating buildup. The cleaning process is very simple. According to Shanks, "You just stroke it clean using a small, steel brush."

In addition to it's neutralizing abilities, the equipment has helped improve substrate quality, particularly in the coating area where static charges can cause "spider webs" on coated materials.

Avery Dennison in Mentor, OH are also believers in the Virtual AC Neutralizer. Their experience with the equipment also began with a field trial.

Jeff Davis, facility engineer at Mentor, had been evaluating competitive static control units. Throughout the tests, static charges were measured using a handheld meter at various times while running different materials using different types of bars, including high-speed bars and blower assisted bars. According to Davis, neither of these styles worked well.

"The Virtual AC system works well at knocking down the static charge," Davis says. "We really like the onboard diagnostics feature that shows the ion output of the bar and when to clean the bar. On the other systems, you're in the dark; you just don't know if it's working or not."

The Mentor plant produces high-precision coated flexible media, including print-receptive topcoats, barrier and pigmented coatings, abrasion and ultraviolet-resistant coatings, tie coats, vinyl casting liner, and release liner products. It runs a wide variety of substrates, including biaxially oriented polypropylene, polyethylene, polyester, polyvinyl chloride, polystyrene, and poly-coated kraft; a wide variety of papers including SCK and MF/MG glassine; and clay coats, all covering a wide range of basis weights. (Substrate suppliers are proprietary.)

Applications range from digitally printed media to prime labels and durable products. Mentor is smaller in size than the Lowell plant and is only four years old.

Denise Mikin, product manager for Engineered Coatings Div., says "Our lines run radiation-cured coatings. We achieve consistent and very thin coatings at high speeds." Dirt attracted by the electrical charge could be trapped in the coating and cause breaks in it's consistency, which could result in poor product performance, she adds.

At Avery Dennison--Mentor, the web is run through a tacky roller web cleaner to ensure that the material is clean. However, the static charge being generated on the material after cleaning was threatening to undo the cleaning process by attracting airborne contamination.

The web runs vertically from the cleaner and then horizontally overhead into the coating unit, creating a convenient walkway through the line. Operators were experiencing static charges when walking through this walkway, so they were required to walk 120 feet around the end of the line in order to avoid it.

Installed just a few inches above a free span of web at the exit of the web cleaner, the Virtual AC Static Neutralizer displays the static levels, giving operators complete confidence that it is safe to walk through the pathway, Mikin says.

The lighted indication bar on the communication module informs operators when bar cleaning is needed to retain effective neutralization. Additionally, operators can now monitor the status of static charge buildup on the web and the corresponding performance of the neutralizing system more closely.

According to Mikin, other static control devices just did not measure up to the Ion Systems equipment. It was the only one to provide the needed diagnostics and the ability to control the static buildup in the manufacturing process.

It continues to be the one and only solution for Avery Dennison.