System Keeps Static Buildup Problems Under Control
- Published: March 01, 2000, By Edward Boyle, Contributing Editor
"It's not a good idea to stick your hand in the mouth of a growling dog." Yet, says Dave Shanks, senior process engineer at Avery Dennison's Lowell, IN, facility, that's the experience many press operators are forced to go through as they test--or, more likely, fail to test--for static buildup on a moving web press. Only by coming in contact with the substrate itself are they aware of a problem, and by then it's too late. Which is why Avery, like many companies, has battled for years to control static on its converting lines.
After testing several other methods, Avery found something that worked: the Virtual AC Intelligent Static Neutralizer from Ion Systems. The system was presented to Avery by Ion Systems as a new device utilizing technology and design previously not available to the converting market.
Mission: Static Relief
Avery's search for "static relief" began several years ago, when Shanks was assigned to research and secure the best possible static control solution available in an effort to improve employee safety and optimize quality control within the company's graphics division.
"Static charges can cross the line between 'nuisance' and 'hazardous,'" David Shanks, senior process engineer at Avery's Lowell facility, says of the common result of static buildup on many converting lines. "The charges that we were generating weren't hazardous, but they could be uncomfortable, and employee safety has always been the company's top priority."
With nearly 16,000 employees, multiple facilities worldwide, and multiple converting operations, the assignment was no small undertaking. The Lowell operation where Shanks works is part of the Avery Dennison Graphics Materials Division producing a broad range of products for traditional printing technologies, as well as wide and narrow format digital printing.
Its products are used in applications ranging from short-term promotional graphics--such as signage, banners, exhibits, displays, and bus wrap markings--to long-term durable graphic applications, including fleet markings, backlit signs, and vehicle striping.
Static buildup on the webs and rolls was not uncommon, and operators at Avery were experiencing static charges while working on various parts of the line, explains Don Hoffmann, process engineering manager. He is responsible for process development, facility upgrades, and optimization, as well as the identification and evaluation of new process or control technologies.
Hoffman notes that in addition to the potential safety risk static poses to operators, static charge on the web also has the potential to attract dirt and dust, violating Avery Dennison's stringent quality control standards.
Shanks and his team tested a variety of devices to eliminate static electricity on the web and rolls. The team found that, on the rewinders, conventional static control bars did not have the performance range needed to properly neutralize material as it wound onto the rewind core.
The only thing that seemed to work was static string and tinsel, says Shanks, but they both collected dirt and could get caught in the splices. "And, if tinsel was allowed to contact the web, it might also scratch it."
In addition, none of the products could communicate their operating state to line operators.
Shanks' hope of finding a meaningful, permanent solution to static control was beginning to look like a mission impossible. Then he learned that Ion Systems Industrial was conducting field trials for a new static control system.
Passing the Test
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 other static control bars on the market.
With the opportunity to evaluate the Virtual AC Static Neutralizer at no cost during product field testing, Shanks jumped at the chance to give it a try. He worked closely with Dwayne Hernandez, a rewinder operator who works with equipment that has been rebuilt in-house. (The facility also runs slitter/rewinders from Atlas Converting and Cameron.)
The bar was installed on the rewinder to neutralize winding rolls of coated and interleaved stock film. Unlike traditional static control equipment, which typically must be located much closer to the web, the Virtual AC bar could be positioned two feet from the core, Shanks reports, easily accommodating changing roll diameters. Line operators were surprised by the Virtual AC Static Neutralizer's ability to effectively neutralize the static charge at such a long range.
Shanks explains that he found most static elimination equipment couldn't work effectively more than a few inches from the web. However, since web widths naturally increase (and decrease) during the course of converting or rewinding, the company required a source of static control that could operate feet rather than inches from the web.
When Dwayne Hernandez tested the equipment, the company knew it had found its solution to web static control.
"Basically, Dwayne wouldn't let me take it away to try on another part of the line," Shanks recalls with a laugh. "We knew the system worked when it passed the 'Dwayne test.' Since then, we've ordered two more units for use on rewinders."
The Virtual AC Intelligent Static Neutralizer from Ion Systems not only eliminates the possibility of static buildup, Shanks says, but also alerts employees when the system itself needs to be cleaned--another major concern in eliminating buildup. "When the ion output decreases, every operator knows it's time to clean the bar. It's a simple ten-second operation to clean it," Shanks points out. "You just stroke it clean using a small, steel brush."
And, it has helped improve substrate quality, particularly in the coating area, where static charges can cause "spider webs" on coated materials. Coating equipment is from Faustel.
Another Plant Comes on Board
Personnel at Avery Dennison's Engineered Coatings Div. in Mentor, OH, are also believers in the Virtual AC Neutralizer. And their experience 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 hand-held meter at various times while running different materials. Different styles of bars were tested, including high-speed bars and blower assisted bars.
"Neither of those styles performed that well," Davis says. "The Virtual AC system works well at knocking down the static charge. We really like the on-board 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.
The facility runs a wide variety of substrates, including biaxially oriented polypropylene, polyethylene, polyester, polyvinyl chloride, polystyrene, and poly-coated kraft; a 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. Smaller than the Lowell plant, the Mentor facility is only four years old.
"Our lines run radiation-cured coatings," says Denise Mikin, product manager for the Engineered Coatings Div. "We achieve consistent and very thin coatings at high speeds." She adds that dirt attracted by the electrical charge could be trapped in the coating and cause breaks in the coating consistency, which could result in poor product performance.
Adding Confidence
To ensure that material at Avery Dennison-Mentor is clean prior to coating, the web is run through a tacky roller web cleaner. The static charge generated on the material after contact with the tacky roller, however, 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 using this walkway. As a result, they had to walk an extra 120 ft around the end of the line in order to avoid it.
A Virtual AC Static Neutralizer was installed just a few inches above a free span of the web at the exit of the web cleaner. The display on the Virtual AC communication module now gives operators complete confidence they will know when it is safe to walk through the pathway, according to Mikin.
The Virtual AC's communication module uses a lighted indicator bar that can tell operators when bar cleaning is needed to retain effective neutralization. In addition, APK/Games/Software Directly from Your Browser operators now can monitor closely the status of static charge buildup on the web and corresponding performance of the neutralizing system.
"We tried other static control devices," says Mikin, "but only the Ion Systems' equipment provides diagnostics. It is really the first time that our operators can interact actively with the static control process."
Two plants, one solution. It equals success in the battle against static.
Supplier Information
Ion Systems Industrial, Windsor Locks, CT; 860/292-6847; ion.com/industrial
Atlas Converting Equipment USA (Valmet Converting), Charlotte, NC; 704/319-3205; valmetconverting.com
Cameron Converting Inc. (Elite Cameron), Piscataway, NJ; 732/627-0400; elitecameron.com
Faustel Inc., Germantown, WI; 262/253-3333; faustel.com
