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Diecutting



The label industry’s changing demands have led to a paradigm shift within the sector.



By Steve Katz



Published January 18, 2012
Related Searches: Flexible dies Digital printing Label printer Label press
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The last few years have turned out to be pretty big for the diecutting sector of the label industry. Apart from recent top stories that include the RotoMetrics acquisition of Gerhardt, and a stronger push from laser technology, the paradigm continues to shift, as more and more converters are favoring flexible dies over solid tooling. European converters by and large have already made the switch from solid to flexible, and experts report that the North American market is embracing the move to flexible more than ever, sold by the economical and lead time advantages, ease of storage, and markedly improved quality and performance of the flexible dies themselves.

Diecutting’s evolution within the industry has everything to do with the trends taking place in the label market at large, as well as the changing demands of label converters. The technology develops in response to material applications. The diecutting sector that featured seasoned, skilled craftsmen is giving way to precise machines, and as one industry expert says, “diecutting is no longer an art, but a science.”

Thin is in

One of the more dominant trends in the label market today is the move towards thinner filmstocks on increasingly thinner PET liner. Brand owners are turning to converters for these thin films not only for material savings, but also for the ability to create specific constructions, such as the no-label look.

The type of material being cut makes a huge difference when it comes to die selection.
Mike Wilks, product manager for printing products and flexible dies, Bunting Magnetics, Newton, KS, USA, says, “One of very first questions we ask our customers is, ‘What are you cutting specifically? How thick is the label material? How thick is the liner? All of that comes into play. Blade angles and coatings depend on that,” he says, adding that there’s also been a dramatic change in coatings in the last two years.

A Electro Optic flexible die and magnetic cylinder 

In terms of material, it usually comes down to either paper or film, and they’re quite different in how each influences the diecutting process. Additionally, with film, the type and thickness of the material is another difference maker.

“Paper facestocks require good edge quality that generates the crush cut, or bursting of the material,” explains Steve Lee, vice president of technology for solid and flexible die manufacturer RotoMetrics, Eureka, MO, USA, “Filmstocks require acute blade angles and precise blade edges to cut to the liners. Manufacturing technology has delivered computer-controlled precision machine finishing to meet the tighter performance tolerances of today’s diecutting requirements,” he says.

With materials such as the thin films required for the no-label look, Lee says it is even more critical to control die strike and depth of cut, as almost no impression is sought on the PET liner.
“Diecutting for these applications requires the most exacting plate height and edge tolerances to be evaluated against specific customer converting requirements,” he says.

Current challenging film-on-film applications include high-speed beverage and battery jacket labels, Lee says. “In these converting environments, our customers are processing 600-950 parts per minute, and require dies with the longest-life possible and ultra-precise liner strike,” he explains. To respond to these requirements, RotoMetrics launched the AccuStar flexible die at the 2011 Labelexpo Europe in Brussels. (For more on AccuStar, see page 56.)

Kocher + Beck also manufactures both solid and flexible dies, and at its US headquarters in Lenexa, KS, the focus is solely on flexible. According to David Morris, senior executive VP, taking a close look at the material to be cut is of paramount importance when it comes to die selection. “When we get an order for a die we look at the material we want to convert. The material determines the cutting angle. And depending on the material, the angle can be
between 45 and 110 degrees.

“If we run into some new material that we haven’t seen before, then we run it through tests. We have several test stations, and dies with different angles. Paper can go with a wider angle because with paper, you are compressing to the point where it bursts. Compression has to be much higher with films – you typically need a steeper cutting angle and higher force,” he says, adding that the steeper the cutting angle, the easier it is to convert, but the sooner it wears out. “A wider angle lasts longer,” he says.

With diecutting, precision is of the utmost importance, particularly with film substrates. “Paper will burst under pressure when compressed 70 to 80 percent, even with a dull knife,” explains Markus Marfurt, president of Electro Optic, Alpharetta, GA, USA. “Film can stretch due to its molecular construction,  and it must be cut all the way through. We are talking sharpness and precision in the parallelity of the knife. Any little distortion or inaccuracy of the blade will cause a problem.”

So, paper is less critical to cut because of the bursting effect, according to Marfurt, but film, because of the need to cut nearly 100 percent through, requires a sharp blade to cut all the way through the film liner. “On a paper liner there is a protective silicone layer. If I cut through that, then my die strike is too deep. If I ink it, and if the ink penetrates, it bleeds through and becomes a visual indication of the die strike. Of course with film you can’t do that. There is no possibility to verify the die strike quality on the machine side for film liner. So it comes down to counting on a reliable flexible die system,” Marfurt says.

Die Treatment

Both solid and flexible dies are not ready to cut once they’ve been manufactured. In order to be effective, they must go through a variety of coating and hardening processes before reaching the converter.

According to Mike Wilks, the last couple years have seen significant changes in how dies are coated and hardened. He says, “The biggest changes occurring recently started with laser hardening the tip. You can’t harden the entire die because it will crack when rolled around the cylinder. You have to apply coatings that will give the die extra long life, and will stand up to very abrasive diecutting applications like thermal transfer paper and white ink.”

There are a range of coatings available, and finding the right one takes some trial and error, Wilks says. “Chrome, titanium nitride, chrome nitride, there are many different types of coatings, and that’s where experimentation comes in – to find which work best for which application,” he says.

Coating can also be difficult. Explains Wilks, “They have to be applied using vacuum chambers – a vapor deposition process. You can’t just dip the dies. That’s a very uneven process.”







A Nilpeter press with a Bunting Magnetics
flexible die and magnetic cylinder


According to Wilks, new lines of chemical coatings are starting to come into play. He says, “Some types of glues build up on the die. We’re using Teflon-type coatings that adhesives will not stick to. With film, PP and PVC are for basic higher run types of labels. Then you have Tyvek, foils, polyesters, etc., which tend to be a little more on the abrasive side, with imprecise thicknesses, and are more difficult to cut,” he says.

Wade Fouts, vice president of sales at Wilson Manufacturing, St. Louis, MO, USA, emphasizes the differences in two coating styles – for films and papers. “They’re different because the way the coating applies to the tip of the blade. You can’t have coating round off the sharp edge for films. That’s why paper dies last a lot longer. Film dies have to cut all the way through.”

Fouts points out that some people are getting into laser hardening because of film-cutting requirements. “Because there’s no coating on it, you build the die to have a razer sharp angle. It cuts cleanly. With a laser, you don’t have to worry about coating effects, and this makes it more durable,” he says.

Fouts emphasizes the importance of angles. “It’s like laying your steak on a table and trying to push a butter knife through it.  You can’t let film stretch, and some are worse than others. You have to have the angle thinner because you don’t want stretching of facestock, just slicing. So you have to adjust the angle to the film.”

Kocher + Beck attributes much of its dies’ effectiveness to its sharpening process. “We have always put a lot of emphasis on quality and technology in making our flexible dies. We use a special alloy that the steel mill makes for us – there are special components in there. Plus, we have been machine sharpening every single one of our dies for the last 20 years. We’re specialists in that, and use our own equipment, and are dies can hold tighter tolerances.”

While the general consensus in the label industry points to a focus on flexible dies, solid tooling still has a presence, and to some degree, always will. For starters, there are simply some substrates that a flexible die just can’t cut; they’re just too thick. And while thin films are trending, there will always be a need for labels made from thicker materials. Also, some label die customers are branching out and converting products apart from PS labels. For many of them, solid dies are the way the to go.

Sohn Manufacturing, Elkhart Lake, WI, USA, offers all kinds of converting products and services, and counts custom diecutting among its specialties. In business for 60 years, the company has seen the evolution.

Harvey Beaudry, technical sales, discusses how diecutting has shifted, but also says that the quality of solid tool sharpening is also improving. “We were the first ones to use a full CNC machine to complete a rotary die back in late 60s,” Beaudry says. “Everyone else was still hand sharpening. Today we fully CNC-machine sharpen and finish. Edges come out very true and accurate, and it leaves us open to a lot of possibilities because we can tool the edges. We use special heads on the CNC to put a nice edge on them, and we can use harder steels.”

Sohn offers both solid and flexible dies, but acknowledges where the industry is headed. “Years ago, the label market was about 80 percent solid. Today it’s reversed. When people buy small label printers from us, they buy mag cylinders,” he says, referring to the initial investment needed to enter the flexible die arena. “Our solid customers are primarily customers who don’t want to first the buy magnetic cylinders they need. But also, many of these customers are not just cutting labels, but converting parts for rubber, foil, special film, and even thicker nonwoven materials – not ordinary stuff. We even push rotary dies to the limit where the competition won’t make dies for them – medical, automotive, electrical, food packages – we’ve made some recently for a company that makes fabric softener pads. And it’s still a great choice for high volume runs,” Beaudry says.

The Investment

Perhaps years ago, the idea of investing capital in a number of magnetic cylinders and then having to go out and buy the dies themselves was a turnoff to some converters. But as the label industry gets educated, this is no longer the case.

Bunting Magnetics, a longtime manufacturer of magnetic cylinders, only started making flexible dies four years ago. “Actually, we were forced to do it,” recalls Mike Wilks. “We had been manufacturing magnetics cylinders for more than 40 years, and we sold to people who manufactured dies. Then there was a change in the industry; they were asking for pricing that we couldn’t match. It became a major discount situation where they were giving away the dies.
Today we price at what the market rate is.”

Is there competition for magnetic cylinders? “Absolutely,” says Wilks. “It’s between foreign and domestic, and it continues to be a price war – not so much for the cylinders, but for the die business. It’s like a gun and bullets. Anyone who buys a gun realizes he can’t do anything with it unless he has the bullets. The profit is in the bullets.”

How many magnetic cylinders does a label converter need?

“With 20 cylinders, done intelligently and logically, you probably can replace a considerable amount of your solid tool inventory,” states Electro Optic’s Markus Markfurt.

Wilks says the number is entirely dependent on the type of labels being cut and what the repeats are. “Typically four or five repeats will take care of about 85 percent of your jobs. If running the same models of presses, they are interchangeable. Cylinder prices are very affordable today, and have not gone up as much as other types of products in this industry,” he says.

The Savings

So what are flexible die users getting from the investment? At the end of the day, they’re simply saving on costs.

Electro Optic’s Markus Marfurt emphasizes what he sees as the big picture. “If you spend $100,000 in solid tools, that amount can be cut down to $35,000 as flexible die user. That is the driver. A flexible die is no longer an alternative to a solid tool. Flexible dies are the new industry standard,” he says.

The savings can be found in a few places, namely sharpening, shipping and storage. “With a solid die, the body and shirt is fused. With flexible dies, the dies come apart from the cylinder. With solid, every time you need a new design or shape, you have to buy a new body and shirt. The body for flexible dies allows the exchange of different dies  designed on the same repeat. You’re spending money on the ‘shirt’ only.  And when you have to re-sharpen a solid tool, that’s as expensive or even more expensive as a flexible die,” Marfurt adds.

Apart from cost savings, a significant advantage Kocher + Beck’s David Morris points to is delivery time. “We ship 85 to 90 percent of all of our dies within the same day. If we get an order by 11 AM or noon – and it’s not overly complicated – we ship the same day,” he says. “And freight charges are quite a bit lower. Plus, you don’t have to deal with resharpening. If you resharpen a solid die twice, freight costs are already more than a flexible die.”

The ability to more easily and affordably customize diecutting is also driving the move from flexible to solid tooling. “The trend is toward customization,” states Kevin Deckard, plant manager for Atlas Die, Elkhart, IN, USA. “Customization has driven the change behind the demand for different materials as well as the shift from solid to flexible,” he says. “In world of flexible dies, where we are positioned, we are the specialty house. We do a lot of specialty work – stuff that’s somewhat of a different application, with custom materials, and a wide variety of synthetic materials.”

Not only do converters want customized dies, but they also want it customized to their timetable, which is generally ASAP. “The most significant thing for us is lead time,” Deckard says. “Everyone is working under the crutch of needing it tomorrow.”

Another advantage is in inventory and convenience. Mike Wilks says, “It’s a lot quicker for a converter to have a series of magnetic cylinders and a drawer full of flexible dies. And if the die happens to be worn, we can get one out within 24 to 48 hours. With a solid tool, factoring in shipping time and sharpening time – it’s a huge cost difference.”

It’s important to note that throughout the economical advantages, flexible die users are not getting an inferior product compared to their solid counterparts. “Today, the quality is phenomenal,” says Wade Fouts. “And it keeps getting better. More people are moving away from solid, and the level of quality with flexible keeps going up.”

Lasers

While the main story here is flexible dies’ surge in popularity over solid, there’s a third wheel – laser diecutters. Ideal for short runs, and with the industry’s influx of short run work, the technology is a natural fit.

Labelexpo in Brussels had more lasers than ever before featured at the show. One company exhibiting was Spartanics, Rolling Meadows, IL, USA, a company that has been in the laser business for years, and then got into the label market. Mike Bacon, VP sales and marketing, says, “We’ve seen the demand for lasers in the label market grow, so there’s now some validation. Certainly there’s been a lot more acceptance in terms of costs versus tools. We’re working with Avery, FLEXcon and other suppliers to make it better,” Bacon says. “In general, the quality is there or approaching what label printers need. The industry is looking at flexo speeds. If you’re cutting smaller labels across the web you’re not going to hit 300 fpm. We had to take a step back and be in line with the digital guys – quick changes, no plates.

“Uptime on a laser cutter or digital press has to be as fast as you can get it to be. So we’ve focused on quick changeover, and no tools. This was our initial approach – how fast we are,” Bacon says. At Labelexpo, Spartanics demonstrated its new X140 Laser Cutting Station working in-line with the INX NW140 UV Digital Narrow Web Printer. The system combines continuous printing and converting speeds of up to 30 m/m. By combining UV digital printing and laser converting, this system eliminates rotary diecutting tools and printing plates for quick turnaround of high quality labels.  Label converters get multiple advantages by eliminating delays and expenses for tooling, and also by automating cutting paths for faster web speeds.


Kocher + Beck uses a laser hardening process
that extends the life of its 3L flexible dies.


The laser beam can be controlled for defect-free cutting, eliminating burnthrough marks or pinholes at the start or stop of cutting. “That’s the cornerstone of all models of Spartanics laser cutting machines,” Bacon says.

Delta Industrial, Minneapolis, MN, USA, designs and manufactures laser diecutters that could be integrated into a press. “Basically, we will get the customer’s requirements and size the laser accordingly. It’s really nice for short run work,” explains, Jason Newville, design engineer for Delta.

“The machines can be incorporated onto a press,” Newville says. “Generally, we sell them with rotary diecutting machines – six or seven rotary dies and a laser. We put the laser on a robotic arm with a servo motor. You tell it which station you want on the screen and it will go from there. Diecutting can be done before or after lamination, and can be rotated up and out of the way,” he says. “Most of the machines that have lasers are on a diecutting machine, so you can do either/or, and they’re custom-made, with unwind, the laser and rewind station.

“We sell to a lot of contract converters that run a lot of different types of jobs – a lot of medical products, automotive products like gaskets. It’s not geared toward the label field, but more toward abrasive material, like sandpaper or flexible foam adhesive parts,” Newville says.

In terms of speed, Newville notes that Delta’s machines have cut at 50 fpm, and can run faster on a basic shape. “One customer wanted to go 90 fpm so we used two lasers. Speeds depend on the jump speed, how long it takes to get from one image to the next. If we do any laser ablation, it’s a different type of laser, but we may have more than two.

“Right now, customers are trying to see where it fits with their business. For sampling and short run jobs, to try and win the business, then maybe after getting the job, they’ll go to a steel tool. As people learn more and more what it can do, they can get more jobs in-house.

In the diecutting world, people talk about precision, and as Newville concludes, “A laser can cut a hole smaller than a tool can.”

Introducing ThinStream

A new diecutting technology, called ThinStream, developed and recently introduced by pressure-sensitive label material manufacturer Avery Dennison, allows the diecutting of labels with a liner as thin as 12 microns, half of the current minimum in the market. ThinStream also eliminates die strikes, one of the industry’s top quality concerns. The patented technology for ThinStream has been licensed to the Gallus Group, which has created the Gallus Cold Die Unit to accomplish this advancement in diecutting technology.

ThinStream is being touted as a significant advancement in diecutting. Until its arrival, diecutting liner with calipers below 23 microns was considered virtually impossible. With conventional kiss-cutting, the die can cut through the liner and cause operational and quality problems during converting and dispensing. Avery Dennison’s ThinStream technology overcomes this challenge by separating the facestock from the liner before diecutting. It cuts the label shape through the adhesive and then reassembles the label. In order to make a “clean cut,” the machine uses a cold die unit, which is kept below freezing to prevent the adhesive from sticking to the die.

Avery Dennison ThinStream is a result of the company’s collaborative innovation strategy. “Creating real breakthrough products by engaging with label converters, machine manufacturers, designers, brand owners and raw materials suppliers is the core of this strategy,” says Don Nolan, group vice president, Label and Packaging Materials, Avery Dennison.

“We wanted to combine our extensive material manufacturing expertise with technologies that allow us and our customers to further enhance label performance while also reducing liner waste and providing environmental and cost benefits,” Nolan adds. “ThinStream is proof that collaboration across key industry disciplines places Avery Dennison and our partners at the center of a whole new wave of innovations in the label and packaging industry.”

One-cylinder cutting

In 2010, Omet, the label press manufacturer based in Lecco, Italy, announced the release of its “Monotwin” diecutting system for the label industry. The Monotwin system is designed to simplify the diecutting process while reducing costs. The key to this system is the use of a single magnetic cylinder for all label sizes, thereby eliminating the need for the converter to stock a range of different tooling.

The MonoTwin operates by rotating at a constant speed during the cutting phase, while its servo controlled motor allows it to adjust its idling speed to the acceleration and deceleration of the press while staying synchronized for the next cut. The unit is simple and intuitive to use, eliminates the need for a hoist to lift heavy cylinders, and completes a changeover in seconds by simply replacing the cutting sheet.

Operational control of the unit, web tension, and waste extraction are all carried out via the main operator control board, while pre-register and register control is fully automatic. The unit is available for both the Omet X-Jet (digital) and Omet X-Flex (flexo) series of presses.


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