The Leading Edge of Finishing

Just off Route 2 along the northern edge of Massachusetts are the past, present, and future of folding carton production. At Boutwell Owens, a folding carton printer and converter in the old New England mill town of Fitchburg, two massive Mitsubishi offset presses and some flatbed steel-rule diecutting machines of assorted vintages do much of the heavy lifting, while an HP Indigo 30000 and a new Highcon Euclid II digital cutting system take on a growing stream of short-run, fast-turn, prototyping and customized work.

All three presses are kept busy with a steady flow of folding carton printing while the flatbed diecutters turn the printed sheets into stacks of cartons ready for shipping to contract packagers. Steady demand keeps the presses busy, with a full second shift about to be added for the HP and Euclid that sit 20 feet apart in a separate room.

“Quantities drive this, and how things are evolving,” says company President Ward McLaughlin. “Brand owners are pushing the limits, so we do, too. Our digital capabilities help customers with phase-in and phase-out of products, promotional versions, and different effects. Digital lets us do this very cost effectively, especially for samples, such as new versions of a container, or prototypes.”

“No one wants to hold inventory,” adds Bill Lorenz, vice president of operations. “We were spending about half a million dollars on solid dies a year. Now we’re seeing that declining, which is a win for us and our customers.”

Prior to having the HP 30000, sample cartons would be CAD output that was laminated, then hand-trimmed to provide a single sample of what a new carton would look like. “Today we can make a sample that is identical to the actual production piece, so it can be examined for practical use, fillability, and so on,” continues Lorenz. “Before, customers would have a concept or idea and hoped it would come out okay. Now they can know. We give them a real carton that is the same as what they’ll get in production.”

How it works

In most cases, a carton design comes from the brand owner or its ad agency/design firm, usually as an AutoCAD DXF file (Drawing Exchange Format), a data file used for interoperability between AutoCAD and other software and hardware. The file is used to produce a CAD plotter drawing on translucent paper showing all the cuts, scoring and trim marks for the job. A version of the same file is also used by the laser cutter that carves the grooves in the wooden boards that hold the die knives and rubbers used for traditional flatbed diecutting. The translucent CAD drawing is commonly overlaid on the wooden board used for the steel-rule dies to verify accuracy of the intended cuts.

The DXF file can also be used on the Highcon Euclid II, first for placing creasing ridges made of UV-curable polymer on a rotating, drum-mounted Mylar sheet, then for informing the laser where to cut, trim, and perf the substrate. When a test sample comes off the Euclid, the same translucent CAD drawing can be placed on the test print to ensure all the cuts, trims and scoring are properly aligned. Then, if a test-folding of a printed and cut sample shows a carton will work as intended, the job can be run on the HP 30000 and cut on the Euclid.

Speed differences

A laser-cut board ready for dies

For short-runs, this process can take hours out of the production cycle, explains Lorenz. Setting up a conventional flatbed cutting plate takes about two hours, but can take longer for those with complex requirements. While the actual diecutting on conventional machines can take place very quickly—up to several thousand per hour—it is really most cost-effective for longer run jobs and large production volumes. For the growing number of short-run jobs that are the domain of the Euclid, the Mylar sheet used for scoring can be prepared in 15 to 30 minutes. Then, each printed sheet, fed from a stack via a conveyor belt, is scored by being pressed between the Mylar sheet and an anvil roller, then passed into the cutting station where an array of lasers do the cutting. Overall throughput is 1,500 sheets per hour for 28˝ x 40˝ sheets. Waste material is stripped away and falls beneath the machine.

“We don’t see this replacing conventional dies,” affirms McLaughlin. “But, it has enhanced the world by aiding creativity. For brand owners and package designers, everything they were told they couldn’t do, they now can do. In addition, because the laser can do far more complex cuts than is possible with a flatbed die, designers can do more intricate things that can make a product shine right off the shelf. And they can do it affordably.”

Dave Pung, vice president for LaserSharp Equipment at LasX Industries, agrees. “A medical device company can have a dozen products with 2,000 different packaging needs such as private labels, different countries, FDA changes, and more. All highlight a dynamic need that traditional packaging and finishing cannot meet.”

Laser cutting also offers the ability to package and deliver labels or cartons in a sequence or special grouping that simplifies or even eliminates manual steps that take place downstream of printing and finishing. “A laser cutter,” says Pung, “can also be part of an automated workflow, using instruction sets contained in a 2D barcode printed on the side of the waste matrix. And [lasers] can be scalable, so as a business grows, so does the capacity of the laser system, and that can increase capacity.”

Still cutting after all these years

Lasers may have a certain “wow factor” but they are not about to replace mechanical systems. Like the digital presses they are often paired with, lasers are attuned to shorter runs, but are not the only way to handle shorter jobs. Flexible and solid dies still have a secure place in the market for both labels and folding cartons produced on flexographic presses.

While most folding cartons are produced on offset presses, flexo has a lot to offer, especially with its ability to offer hot and cold foil, coating, lamination, and more, all in line. Then there’s speed: On a properly set up flexo press, hourly throughput can be much faster than an offset press with steel rule dies. However, the caveat is that the chosen press must be capable of handling the heavier paperboard (usually 14 pt. or higher), which requires stronger tension controls (think servo motors), larger diameter rollers and idlers, perhaps different gearing, a waste removal system, and a stacking or shingling system for the finished product. Not all label presses are up to the challenge. But if yours is—perhaps with some assistance from your press vendor—you still need to think about diecutting, which has somewhat different requirements than do labels.

Fortunately, the die suppliers are ready with lines of solid and flexible magnetic dies for folding cartons. One favored approach is the male/female die which provides a cleaner, more accurate cut or crease on the thicker substrates used for folding cartons than the single edge used for labels. The process can also require less pressure than through-cutting a substrate against an anvil, which can be very important for some applications.

“Our male/female solid rotary tooling sets take the place of a solid tool and anvil within a conventional station,” explains David Morris, president of Kocher & Beck. The company’s tooling is supplied for machine widths up to 17˝ wide, although wider tooling is available. The tools are manufactured to match the exact material being converted, to help ensure optimal creasing. The tooling incorporates a timing gear on the top (male) tool to allow for fine advance/retard adjustment in relation to the female tool, as well as locking rings for exact lateral alignment. New sets are normally supplied fully marked and timed, ready to go straight into the press, without the need for adjustment.

Morris says flexible dies are still an option, but require investing in two matching magnetic cylinders. However, once a customer has the repeat sizes required, the use of flexible dies can reduce the tooling cost going forward when compared with solid tooling. As with the company’s solid dies, the top cylinder is supplied with a timing gear for fine adjustments.

According to Wade Fouts, vice president of sales at Wilson Manufacturing, his company’s male/female die sets are available in widths up to 28˝ and come replete with hoisting tabs to facilitate lifting the dies into place on a press. Based on design specifications, the dies are designed to be in correct timing with the press when lowered into position. For fine tuning, each set has gears that allow for alignment both laterally and in web direction. Wilson’s male/female die sets can be configured for single-station or multi-station converting and often include vacuum inserts for waste removal, pin-stripping, and air ejection, making them a good fit for tags, cartons and blister board production. Fouts says die sets can be delivered in five to seven working days and can typically be re-sharpened three to four times before being replaced.

Rotometrics offers a line of solid and flexible magnetic folding carton dies, typically for crush cutting, and is introducing a new Rotary Pressure Cutting (RPC) process that uses two flexible dies. These use a male/female configuration and can be used for both cutting and creasing, says Uli Kretzschmar, product and business development manager at Rotometrics. Available in widths up to 35˝, RPC dies were designed specifically for folding carton and liquid packaging applications where crush cutting is not an appropriate technique. According to Kretzschmar, RPC dies—which require dedicated converting equipment—can handle up to 30-pt. paperboard, providing a powerful option for webfed carton production.

One essential part of mechanical diecutting in folding carton production is cleaning up the debris leftover from punching, trimming and other diecutting steps. Look for vacuum attachments for catching and removing waste, and air ejection for removing slugs from the web. Attachments can include vacuum cylinders that mount to the frame of the press, and anvil scrapers to prevent waste from collecting on the anvil and affecting cutting accuracy.

Still another option

Another approach, especially for short runs, comes in the form of flatbed cutters from Kongsberg and Zund—machines often used for signage and POP displays. These use vacuum suction to hold the printed substrate in position on a flat cutting table while a software-driven cutting mechanism scores and cuts the carton shape to provide ready-to-fold cartons. Depending on the model, these machines can accommodate 28˝x40˝ or larger sheets and can run largely unattended.

No matter the size, folding cartons deliver eye appeal, provide product protection and can offer distinctive branding opportunities for an astonishing range of products. And the many ways they can be printed, scored, trimmed, and folded ensure that small folding cartons remain a vital packaging option.