- February 01, 2001, Robert W. Marsh, Contributing Editor
Today's converting industry is a sophisticated one. If you have any doubts, check out a few of the ingenuous ways converters and suppliers have found to solve some tough problems.
As recently as a few years ago, converting was considered a "black art." Today's technology, however, has replaced the magic with sophisticated equipment that was unforeseen back then. The innovations we will cover in this report are shining examples: neutralization of static electricity; coating and laminating lines that run as fast as 1,500 fpm; a 28x40-in. rainbow sheet with only one plate line; tight-tolerance rubber rolls; and a breakthrough in organic light-emitting diodes.
Taking the Pop Out of the Web
At Avery Dennison's (averydennison.com) Specialty Tape Div. plant in Painesville, OH, static electricity has always been a serious problem. The plant manufactures a variety of pressure-sensitive adhesive tapes using several different substrates, including paper, polyester film, foams, nonwovens, and foils.
In production, webs are unwound, coated, laminated, rewound, and slit—with static electricity popping every step of the way. At least it used to be that way, until senior electrical projects engineer Terry Cameron experimented with a Virtual AC Intelligent Static Neutralizer from Ion Systems Industrial (ion.com/industrial).
"I set it up on a slitter," says Cameron, "with a product I knew was particularly hot. It runs at fairly high speeds, so it is a good static generator. Historically, static electricity arcs leap from the web to the machine...snap, snap, snap. And every time you hear a snap, you know the static destroyed the silicone or the adhesive at the point of origin. We measured the static at about 40,000 to 55,000 volts. Then we mounted the Virtual AC neutralizer bar four inches from the web, and in a fraction of a second, the static fell below 150 volts."
Before he found the Virtual AC neutralizer, Cameron relied on tinsel and conventional static bars. To be effective, he says, tinsel must be placed about an inch from the web. He adds, "The faster the web goes, the better the tinsel works. Yet, the best it can do is about 2.5 kilovolts." And, according to Cameron, if tinsel breaks or is tied to a painted surface, it won't work at all.
"Conventional static bars also have their problems," says Cameron. "They have to be placed within an inch of the web. If the web breaks, and you have a speed of five or six hundred feet a minute, the web can curl around that bar and take it through the machine. It upsets the maintenance people. Not only that, as the diameter of a roll increases or diminishes, the bar must be moved to stay at that inch, or it won't suppress static effectively."
Cameron installed several Ion Systems static neutralizer bars on slitters in the finishing department for evaluation. "We've been using them for about a year," he says, "and we've had a very positive response from all of our operators. They've sought me out on the floor to thank me for installing these new bars. They haven't had any shocks, and they're really happy about that."
The static neutralizer bars can be connected to a computer that provides a graphic view of the Virtual AC neutralizers. The system simultaneously monitors and displays neutralizing current, ionizing efficiency, and electrode contamination (which notifies the operator that the time has come to clean the bar). Individual static neutralizers can be monitored, or the entire system can be controlled from the screen. All the neutralizers in the system can be turned off and on individually or all at once.
Innovator Brings Coater Up to Speed
They built their first coater/laminator in 1992, but they're not an equipment manufacturer. Their business grew by 350% in the last three years, but they're not a Wall Street hot shot. They are Technical Coating International Inc. (tciinc.com), a Leland, NC, converter running four coater/laminators that were built internally and are operated by about 75 employees.
Says president Burt Moody, "All four of the coater/laminators were fabricated with our own personnel using purchased basic steel and sheet metal. They achieve line speeds in the range of 700 to 1,500 feet per minute."
How do they do it?
"With precision tension controls and some unique web handling equipment that we designed and built in our own plant," Moody explains. "Webs go straight from the unwind through the gravure coaters, ovens, laminator section, and on to the winder, all in one pass. We can do one side twice—that's two hits—or we can do two sides in one pass." In the two-pass machine, TCI has two gravure stations in line with ovens, laminators, unwind, and rewind stations.
The changes in web handling TCI has developed give the company greater flexibility to run a variety of substrates on their machines, Moody says, elaborating, "From half-mil polyester to 14-point board, without making major adjustments in the machinery."
Improved line speed also depends on the support equipment TCI designed internally. For example, idlers specifically are made to handle thin substrates and the light tensions they require. Web tension is maintained by strain gauges with feedback controls. "The data is fed into a CPU that controls everything," says Moody. "It processes the data, and it goes back to the system and adjusts the drives for torque and speed. Once they're set, the CPU maintains that tension and speed."
The machinery at TCI consists of one 62-in. coater/laminator, two 80-in. coater/laminators, and a 96-in. coater/laminator, plus a Faustel pilot coater, the only commercially made machine in the plant. The 62-in. machine is designed for thin film and foils (0.00025 in.). The two 80-in. machines are designed for paper and thick films and also are capable of converting thin films, as is the 96-in. machine. This equipment handles polyester, polyethylene, polypropylene, saran-coated films, nylon, aluminum foil, nonwovens, and coated fabrics.
Innovation is not a one-time thing at TCI. "It comes from all the employees in the normal course of operations," Moody says. "When someone has an innovative idea, the technical group—headed by a new member of the team, Jessie Tally—goes to work on it with the person who suggested it. The recognition given to that person is one of the reasons we have been able to keep our good employees."
When will TCI build another machine? "Before we need it," Moody says.
Diffraction Grating without Plate Lines
In the beginning of the hologram era, converters and printers had to work around plate lines that occurred every 12 or 20 in. Now, however, the plate lines are gone, and they can create their designs on a 28x40-in. sheet without plate lines. For example, they can lay out cosmetic cartons and nest them across the sheet without interruption. Their only concern is how the cartons can be cut out.
"We didn't get rid of the plate line," says Stewart Glazer, VP of sales and marketing for Crown Roll Leaf Inc. (crownrollleaf.com), "we just moved it out of the way."
For years, Glazer wondered why his customers didn't use rainbows more often. ("Rainbow" is Glazer's term for a diffraction grating that has no design on it.) "We kept listening and learned it was because the plate lines interfered with the way they wanted to lay out their designs."
In response, Crown designed and fabricated a 50-in. embossing machine with a center roller that measures 28 in. in diameter. It uses some components from equipment manufacturers and machines others on the premises.
"So," Glazer explains, "what we have is a rainbow with a 48-inch plate line that gives the customer that 28-by-40 sheet with no plate line. We also emboss an eye mark next to the plate line, so that when we send it to the laminator, and he laminates it onto his paper or board, it's easy to register."
The company offers its SuperFormat foils and films in two versions: 28 x 40 in. and 20 x 28 in. on metallized polyester or oriented PP film.
According to Glazer, these diffraction gratings may be used in personal care, video, software, food, beverage, pharmaceutical, and confection packaging, as well as other printing markets.
One of the most notable applications of Crown's SuperFormat product is a curved, metallized holographic carton for Cadbury's Milk Tray chocolates. It won the Peter Rigney Package of the Year award in the April 2000 Metallized or Vacuum-Coated Package and Label Competition sponsored by the Association of Industrial Metallizers, Coaters and Laminators (AIMCAL).
To produce the design created by Cadbury, Unifoil Corp., (unifoil.com) Passaic Pk., NJ, transfer metallized paperboard from Westvaco (westvaco.com), with Crown's SuperFormat diffraction grating. It is one of seven AIMCAL awards Crown has won in recent years.
How Flat Is Flat?
Manufacturers of products such as optical films, p-s label stock, and window films have sensitive roll coating and laminating operations, and they need to know exactly "how flat is flat." If the roll surface is not truly flat, product quality can vary significantly.
Until recently, manufacturers of rubber rolls had to rely on hand-held micrometers and dial indicators to measure roll diameter variation and overall roll profile. Typically, measurements were taken at only a few locations across the face of the roll. While this technique is reliable for steel and ceramic rolls, it doesn't offer the precision required for rubber rolls.
An innovative laser roll mapping system for rubber rolls was developed in 1999 by Steve Huff, corporate engineer at ABBA Rubber International Inc. (abbarubber.com). The system provides traditional roll measurements with a two-headed laser system that measures the roll without compressing the surface or causing damage to sensitive roll finishes. It can handle rolls to 22 in. dia and 159 in. long. Measurements are accurate to within 0.00005 in., according to Huff.
This new system sweeps the face of the roll at a resolution of 0.002 in. and measures total indicator runout, roll profile and taper, concentricity, and cylindricity. These data are fed into a computer that displays the measurements on a monitor. Customers can access these reports from a secure location on ABBA Rubber's at abbarubber.com.
"Temperature control is critical to the success of this operation," says Huff. "We've seen a ten-degree variation cause a 0.002-inch change in roll diameter. So, our inspection equipment is located in a controlled atmosphere. And before we inspect a roll, we store it for 12 hours in that room so its temperature can stabilize and we can be sure the roll's profile won't change after we inspect it."
ABBA Rubber is a 40-year-old company that specializes in rubber roller fabrication, recovering, grinding, and the manufacture of precision molded parts. It was founded in 1959 and has grown by about 60% in the past seven years.
The Advent of OLEDs
The technology of the organic light-emitting diode (OLED) has been known for more than a decade, but it could never be brought to commercialization because it has a fatal flaw: Oxygen and moisture will ruin it. Yet, the OLED display is much brighter and sharper than the inorganic light-emitting diode and the commonly used liquid crystal display.
"Some OLED molecules are red, some blue, and some are green. Put them all together and you've got full color," says John McMahon, marketing VP for Vitex Systems Inc. (408/524-8160). But the OLED technology needed a barrier to protect it from moisture and oxygen.
"Glass is an effective barrier, but encapsulating an OLED between two sheets of glass isn't commercially feasible because of low yields and high expense," says McMahon. "Besides, we've got a better idea."
His company's product is a multilayer film called Barix. McMahon explains: "To make it, we polymerize a monomer in a vacuum to create a solid polymer. The surface of this polymer is absolutely flat. Surface roughness is below ten angstroms. Then, we sputter aluminum oxide on the polymer layer and repeat the whole process five times. The chances of moisture or oxygen going through those five layers are nil."
Now, OLEDs can be deposited on a sheet of glass, and instead of sealing them with another sheet of glass, they can be protected with Barix encapsulation. The entire process takes place in a vacuum.
A further improvement is on the horizon. "We're going to put OLEDs on Flexible Glass, the Vitex barrier substrate for flexible, flat panel displays," says McMahon. He explains: "To make Flexible Glass, we coat polyester or other plastic film with our Barix multilayer film. Display makers will then deposit the OLED on the Flexible Glass substrate and seal it hermetically with Barix encapsulation or another sheet of Flexible Glass in order to make a flexible, plastic OLED display. This finished display is about 300 microns thick, or about the thickness of a sheet of paper. You could roll it up like a window shade and have a color display in your living room—TV on the wall. You can die-cut it and slit it just as you can paper."
McMahon says displays on Flexible Glass won't be as expensive to make as handling a sheet of glass in a vacuum. "It's unbreakable and doesn't weigh as much as glass, either," he adds.
Vitex expects to produce displays on Flexible Glass by July.
These are just some of the converting innovations making news. This industry has come a long way (baby) from "black art."
Robert W. Marsh, former executive director of the Association of Industrial Metallizers, Coaters, and Laminators (aimcal.org), is a retired marketing communications manager for ICI Americas, where he managed advertising, sales, promotion, and product publicity for Melinex polyester films. Prior to joining ICI, he handled a variety of advertising assignments for the DuPont Co.