Gravure: The other cost-effective process
In November 2004, former Flexible Packaging editor-in-chief Andrew Mykytiuk wrote, “Sometimes, nothing fails like success, and for the longest time gravure was very successful.” To elaborate, gravure learned nothing from its inherent photographic quality or incredibly fast line speeds. But over time, gravure realized it had to do something about ground lost to flexo in flexible package printing. Today, even as flexo continues to improve, cost-effective pre-press procedures, precise registration systems and operator-friendly interfaces further dispel the notion that gravure is an expensive proposition complicated by long, involved changeovers.
Time and moneyOne of the key struggles facing gravure is its bad rap for being an expensive process that requires lengthy pre-press production. Frank Passarelli, North America product manager for Rotomec, asserts that gravure cylinder production, in reality, is cost competitive with flexo platemaking.
“As a general rule, a run-of-the-mill flexo plate will cost about 35 cents per square inch,” says Passarelli. “A high-quality, high-end flexo plate jumps to 49 cents per square inch. The gravure cylinder costs around 50 to 51 cents per square inch.” To increase flexo’s print quality, Passarelli notes the costs likewise increase, whereas gravure costs are fixed. “We don’t have such a thing as a cylinder engraving for high quality and one for lower quality.”
Even if gravure nearly matches flexo’s price point, it still takes forever for a printer to see engraved cylinders show up at his loading dock, right? Not necessarily.
“We’ve been in many situations where [a printer] keeps one roll in the press, one roll as backup and one roll at the engraver,” says David Skellie, president at Interflex, a manufacturer of laser-engraved ceramic coating rolls. “We say keep one roll in the press and one roll in backup. We don’t need to keep one roll because laser engraving is a very quick process: We’re on a two-week turnaround.”
Skellie reminds all his customers that as far as general gravure printing applications go, ceramic rolls probably aren’t the best solution, especially if existing traditional chrome-plated copper rolls work well on a printer’s press. However, Skellie does say that Interflex’s ceramic-coated engraved rolls perform well in lines where a printer may be using very abrasive inks or coatings (like whites containing titanium dioxide or ultraviolet-resistant coatings) that may wear out a traditional chrome-coated copper cylinder quickly.
(Playing) TAPS for wasteful set-upRotomec, the product line and brand representing gravure products under Bobst Group, offers Total Automatic Pre-register Setting (TAPS) with its gravure presses, from its line of MW presses designed for short runs through its high-speed, high-volume RS presses.
Explains Passarelli, “[TAPS] is a patented system that presets the job based on what is printed on the web rather than setting the angle position of the printing cylinders."
Until recently, the cylinders in a gravure press were mechanically preset to match the angle position between one cylinder and the others in a press. With TAPS, each cylinder has an engraved recognition mark that the system detects on the printed web to make its adjustments. After a printer mounts these cylinders in the press (without paying specific attention to their positions), the system goes into a fully automatic mode. TAPS first reads the recognition code printed on the web to determine the position of the cylinder and then, based on the readings, adjusts the register of each cylinder throughout the press.
While the process sounds quite daunting, the time required and scrap generated are anything but.
“Usually this whole sequence takes about five minutes,” says Passarelli. “And the waste that is generated is roughly one and a half press lengths, from the first unit to the last unit.”
Ding, ding, cha-ching goes the trolleyHeine Heininga, rotogravure sales manager for Windmoeller & Hoelscher (W&H), knows exactly what value-minded customers expect out of the latest gravure presses: faster changeover. The Lincoln, R.I.-based company delivers just that with interchangeable cart systems or trolleys on its Heliostar line of gravure presses.
“With the easy interchangeable cart systems, the ink and roll are already integrated on the cassette on your inking pan,” says Heininga. “All the changes that you want to make can be done immediately. The minute you take the cart out, you put the other cart in and your print station is ready to go for your new print job.”
Heininga points out that W&H presses can also be customized to include a fully automated cassette system where a printer pre-loads a cassette consisting of an ink pan and cylinder in an elevator. Literally with the push of a button, an operator at an individual print station can remove the used cassette and slip in the new cassette, without even touching the setup.
“With that option, we also have a cleaning cycle, so the parts that you get out of it are virtually clean,” says Heininga.
Tweaking original ideasFor nearly its entire existence, gravure has been considered a simple, yet rugged printing form. The printing unit of Uteco Converting took this simplicity one step further with Q-Press, designed for quicker changeovers and short runs in gravure. Q-Press features an operator-friendly control panel that allows an operator to adjust nearly any parameter of the machine.
“Every unit is equipped with a color touchscreen that helps change jobs, adjust the drying units and so on,” says Leonardo Gobbi, vice president, International Sales and Marketing at Uteco. Gobbi explains that Uteco’s gravure presses now offer printers the ability to measure the height and angle of the doctor blade for every job and record those settings for repeat jobs. “[Those] can be adjusted manually by the operator at the touchscreen or can be motorized for automatic adjustment of the doctor blade,” says Gobbi.
Uteco continued to innovate on gravure fundamentals by introducing sleeve-based gravure cylinders with on-board sleeve change. The Q-Press uses a mandrel fixed to a servo motor in the press and, like on a flexo press, the operator can slip the old sleeve off, slip the new sleeve on and expand the mandrel to fix the sleeve in place. The engraved sleeves, points out Gobbi, are chrome-plated aluminum, not copper as traditionally found in gravure printing.
Although gravure today represents only 10% of North American flexible packaging printing (according to Flexible Packaging Association’s 2008 State of the Industry report), the printing form still sets standards of quality thanks to key advance-ments, including fast synchronization of print stations and automatic changeover. Improvements in rival formats will also continue, but these advancements and those to come will help gravure maintain its position for producing some of the best graphics around. n
Bobst Group (Rotomec)
Interflex Laser Engravers
Windmoeller & Hoelscher
Web exclusive: Developing tomorrow's gravureAccording to the Flexible Packaging Association’s 2008 State of the Industry report, flexographic presses print nearly two-thirds of flexible packaging in North America today. While the odds of the scale tipping in gravure’s favor are between slim and none, Frank Passarelli, North America product manager for Rotomec, strongly believes the time to invest in gravure’s future is still now.
“Gravure risks [becoming] the proverbial cathedral in the desert,” asserts Passarelli. “The cathedral is great to have, but nobody goes because it’s in the desert. In the case of gravure, most people recognize the process of being unequalled in terms of print reproduction and print quality consistency, however, due to the perception that gravure is mostly suitable for long runs and highly quality requirements, gravure is often overlooked as a viable and competitive process.
“I would urge the industry to start investing in new technologies,” says Passarelli. “Running a 40-year old press to satisfy today’s production needs is, without question, not a cost effective way to compete in this very competitive and demanding market. You can’t compete with other printers that have modern and efficient equipment. But more importantly, you can’t compete with flexo.”
Passarelli believes the key to gravure’s growth is in prepress and explains that today’s cylinders are capable of printing 10 million impressions, while the average run length is more like 50,000 to 60,000 feet.
“So why do we need such a resilient cylinder to produce what we need today? We need to look at different types of print cylinders, maybe get away from the traditional steel base and look toward composite print cylinders, sleeve cylinders or hollow cylinders,” he says.
Passarelli points out that year after year, the flexo industry reinvests in equipment and introduces new technology to reduce changeover time and increase press automation. In certain areas, gravure has started to do the same, and as a result, gravure has made much progress to clean up its image and reduce costs. It is no secret that all print processes try to achieve the quality and consistency of gravure. We often see flexo and off-set printers compare their print results as being ‘almost as good as gravure.’
“In the U.S., a gravure cylinder-depending on the width of the cylinder, the repeat and so on-runs in the range of $1,000 to $1,200,” explains Passarelli. “In Europe, you’re talking about a $400 cylinder and in Asia, $200 a cylinder. If we here in North America, and more specifically, in the U.S., could get down to a $200 cylinder, imagine what that would do for the gravure process in terms of being competitive with flexo.”