Print

Foil Applications



Hot, cold, flat, rotary, solid, flexible, sleeves, rings.



Published July 20, 2005
Related Searches: Label industry Flexible dies UV curing Magnetic cylinders
Post a comment

Everybody's doing it. Foil is where it's at, the big thing, the bling-bling of the label market. Foils make labels shine. They help products sell. "Absolutely we are seeing market growth," says Chris Corbett, national sales manager for ITW Foilmark, Newburyport, MA, USA. "More product marketers are going to foil for competitive reasons, to make their product stand out on the shelves. There is certainly a shift from offline sheetfed offset foil stamping to bringing all of the processes inline to pressure sensitive, or to unsupported film."

"Rollfed foil consumption, generally meaning labels, is our fastest growing segment in the graphics foil business," notes John Thoma, Midwest sales representative for Kurz Transfer Products, Charlotte, NC. USA. "Part of the reason is that rollfed printing, labels in particular, has taken share from sheetfed offset."

Try to find a wine label, a pressure sensitive wine label, that doesn't have foil somewhere on it. High end spirits have gone in the same direction. Labels and packages throughout the health and beauty market are long-time aficionados of the foil advantage, and products of every stripe are following suit.

There are many ways to achieve the foil look: flatbed hot stamping, rotary hot stamping, and rotary cold foil application. A converter can choose among flat dies, solid rotary tooling, flexible magnetic rotary tooling, solid stamping rings, flexible stamping strips, or regular old flexo plates.

Depending on whom you speak with, the opinions differ about one method over the others.

Hot foil

Many converters achieve fabulous quality, and high customer satisfaction, using tried-and-true flat stamping equipment, such as those produced by such companies as Newfoil, Franklin Manufacturing, and Rapid Machinery. The dies used in these units are flat and simple, and cost very little. They are, however, offline machines, requiring a roll change and re-registration.

Inline rotary hot stamping has been a standard for years, challenged only by cold foil application in the past decade or so. Cold foil can be applied using a photopolymer plate, anilox roll, adhesive and UV curing lamp, without heated rollers. Speeds also can be higher.

"The market seems to be moving back toward more rotary hot stamping," says David Stollenwerk, vice president of American Die Technology, Suwanee, GA, USA. Cold foil and some of the magnetic hot stamp options slowed down the solid tooling market for a brief time, but now that companies have had time to see that the quality and the life is not apples to apples with a solid tool, they are starting to migrate back."


American Die Technology's hot foil stamp unit.

I.Kela, of Sarasota, FL, USA, is an ITW company that has been manufacturing stamping units and tooling for many years, and manufactures units for new presses produced by Mark Andy, Comco and others. "Over the past two or three years we have observed that the market for hot stamping has not gone down, but rather has doubled, tripled," says Peter Kuschnitzky, general manager. "Most of the units we sell are going into brand new presses to customers who are upgrading their capabilities. They are going onto presses that are totally interchangeable, modular units that can be interchanged with screen units, for instance."

Rotary hot stamping involves a station somewhere along the inline press whose stamping tool is heated either by oil or by electricity. Oil seems to be popular, and is mentioned by many in the industry as offering the most consistent heat, especially at higher speeds.

Depending on the foil being applied, the heat range will differ. The use of heat to stamp foils into substrates also determines the speed at which the press will run. If the speed is too fast the stamping die will exhaust its heat more quickly and the foil transfer could then be incomplete.

"You can have a gauge on a press that says 290? F, and how much heat is being transferred to the thermally active adhesive will depend on whether you're running at 100 fpm or at 300 fpm," says John Thoma of Kurz. "One of our products requires a temperature range of 284? to 338? F on rotary machines. Another is 338? to 428? F. That's quite a bit of range.

"People want things to run fast," Thoma adds. "If the press is running slowly, 90 percent of the time foil is the determining factor; the foil will slow down the whole press.

"A lot of operators will set the temperature of the die to the practical limit, say around 390? F. They run the foil at 200 fpm and it looks beautiful. Then they go faster, and faster. Then they reach the point where the foil is not fully transferring, but shows little pinholes. It's their experience that you turn up the heat and start running. It doesn't matter what the foil guy says about his foil or what the die guy says about his die."


The Omega Digicon converting machine from AB Graphic International can be supplied with semi-rotary hot foil stamping, which eliminates the need for various cylinder sizes.

"The biggest thing that we've achieved is the development of a foil that is overprintable by UV curable inks," says Corbett of ITW Foilmark. "It's quite easy to print with conventional flexo over foil, but overprinting with UV curable inks has been a challenge. We have developed a chemistry, a topcoat that goes on the foil. It alters the surface tension and polarity so that it is acceptable to UV inks." The newest version of the foil, out for about three months, allows for printing at speeds that can reach 175 fpm.

"End users want the shiny look of the foil, but where does foil fall in the press itself?" Corbett asks. "If it's just at the end, it limits where and how you can use the foil. The key is to have the flexibility of a foil printing station anywhere on the press ? lay it down, trap around it, overprint it ? don't just limit yourself with a drop-in station at the end of the press." Many newer presses have moveable foil stations.

Solid brass hot stamping cylinders are costly. One method of utilizing solid brass hot stamping without the cost of a full cylinder is to utilize brass rings that mount on a special cylinder. "The rings are lightweight, they save cost, but you get the full effect of brass rotary stamping," says Bill Reichard, president of Gerhardt USA, Dallastown, PA. "They are great for people who do multi-row foiling, with small foiling areas." The rings are usually only a couple of inches wide, and are cheaper to ship and deliver faster, Reichard adds.

Flexible stamping


Bunting Magnetics' Gold Series cylinders are used with the company's patented rubber foil stamping plates.

Cutting dies of thin metal wrapped around magnetic cylinders are growing in popularity, and so are flexible stamping dies. RotoMetrics, the world's largest producer of narrow web dies, based in Eureka, MO, USA, markets both solid and flexible foil stamping dies manufactured by Universal Engraving in Overland Park, KS. "We have seen orders of flexible stamping dies double over the past year," says Gary Smith, VP of RotoMetrics.

"The advantages to some converters in using flexible tooling is that the replacements are a fixed cost (a square inch price, regardless of design intricacy), less expensive than a solid tool, changeover is quicker, and turnaround time in manufacturing is shorter than that required for solid tooling. The quality of the stamped image is very comparable," he adds. The flexible hot stamping tools marketed by RotoMetrics are called UniFlex.

Most flexible dies are all metal. Bunting Magnetics, however, recently introduced a steel backed rubber plate for hot stamping. "With a metal plate you need a rubber impression roll, but with a rubber plate you use a basic anvil cylinder," says Tom Gray, product manager for Bunting, of Newton, KS, USA. The company has sold four of the hot stamp systems a month since the introduction last year, Gray says.

The plates for the system are proprietary, and average $3.75 per square inch. Turnaround time is normally 48 hours, according to Gray. "The life span is about the same as for a flexo plate, anything from a half million to a million impressions. If you're using the right foil and paper substrate, you can get up to 250 fpm. With film and foil that requires higher heat, it could be 100 fpm."

Cold foil

"Cold foil is just like anything else in our industry: If you don't have the right anilox, inks, curing system, and plates, you won't get the right result at the end of the day." That's the advice of Dan Plash, sales manager from Telstar Engineering of Burnsville, MN, USA, which manufactures custom equipment for the label industry.

Cold foil transfer utilizes a basic flexo station to apply adhesive to a plate, which transfers the pattern to the substrate. Foil is nipped to the substrate, and the foil is transparent enough to admit UV light to cure the adhesive and bond the foil.

"Support from foil and adhesive suppliers has increased and improved greatly," Plash says, "and we now have adhesives and foils that work with a wide variety of materials including some that previously could not be hot foil stamped (i.e., shrink film or any type of heat sensitive material). The weakest link, in my opinion, has been the do-it-yourself with existing equipment attitude." Telstar manufactures a self-contained cold foiling unit, the Deco-Mod, a servo driven flexo station with a nip roller, UV lamp, stripping roller, unwind and rewind, together in one module. "We have created a web path that makes the process very consistent," Plash says.

The cold foil process can allow the operator, in some cases, to run at higher press speeds, adds Plash. "Operators who are used to doing hot stamping run the press at 100 to 150 fpm, but they can ramp it up with some cold foil runs. The results are cleaner at higher speeds on certain substrates, I have found. Some films run better at higher speeds. It seems that paper runs better faster, but not in all cases."

Throughout the early years of cold foil, some converters have questioned whether the process can deliver the sharp edges that hot foil is capable of producing. Plash says that it's possible. "You can put a crisper line on film with cold than with hot," he says. "It has to do with having the entire combination right. Unwinds and rewinds are extremely important. You want to have low minimum tensions. If you have to increase tension it's because the web path isn't right. A lot of times the operator will turn the tension way up because they have a baggy edge, and they end up putting more tension on and pulling the web too fast.

"The trick is that when you nip the foil to the substrate you must cure it right away. When you nip it's a wet lamination, and you are asking a light foil and a heavier paper to travel three feet exactly together. If foil has too much tension you have a mismatch, and you'll get a fuzzy edge."

Some industry watchers say some converters tried cold foil and have returned to hot. Not everyone agrees.

"When cold foil was introduced, the process didn't use the so-called through-cure process. It took a while to figure out, and those who have it today are running fine with it," says John Thoma.

"Today it's virtually indistinguishable on smooth substrates. Hot foil has advantages on dry stocks. You can tell the difference with those ? cold foil is not as good a look; the rough fibers don't get stamped down as much. On film, there's no difference between hot and cold."



blog comments powered by Disqus
Top Searches
L&NW ENewsletter
Sign up now to receive the free weekly newsletter

Enter your email address:
Top Articles
Follow L&NW On