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Servo Power



Servo driven presses, growing in popularity among many converters, can offer reduced waste, tighter registration, and faster changeover times.



Published January 14, 2009
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Servo Power



Servo driven presses, growing in popularity among many converters, can offer reduced waste, tighter registration, and faster changeover times.



By Jack Kenny




Servo motors drive the Comco C1 packaging press
from Mark Andy.
Servo motors have been powering narrow web presses for about a decade. Prior to that they were too expensive to incorporate into the press, but it seems that overnight the prices came down and the technology went up. A servo press still costs more than a conventional mechanical press, but some industry observers predict further price reductions in the future.

Credit for the introduction of servo drives in narrow web presses goes to the Europeans. (Three companies claim to have been the first to bring servo power to the industry.) By the early part of this decade, converters were looking seriously at the technology, and acquisitions were starting to build steam. Now, however, servo driven narrow web presses are part of the industry landscape. They represent a minority of printing machines, of course, but among new presses they hold a prominent position.

“The number of servo driven presses in use among label printers is currently small, but that number is growing,” says Mac Rosenbaum, vice president of Aquaflex, a division of F.L. Smithe, Duncansville, PA, USA. “Currently 90 percent of all Aquaflex presses produced are servo driven. Label converters are beginning to take advantage of the added capabilities of a servo press – specifically, the ability to run film. This product diversity is helping them grow and prosper in an increasingly competitive environment.”

 
The Comco C1 press
“The level of penetration overall is still low, but it is making steady gains,” says Jeff Feltz, director of product management for Mark Andy, St. Louis, MO, USA. “The advent of single servo implementations, like the 2200 Servo, has brought servo technology to a more affordable price point for a larger percentage of customers. Converters who have owned traditional mechanical line shaft presses are looking for equipment to reduce their costs and provide more capability. Customers looking to make significant gains with servo are looking at presses with dual servo driven axes, like the XP5000. Dual servo axis presses provide significantly greater benefits in changeover and waste reduction versus single axis servo implementations.

Steve Leiben of Matik North America is the sales manager for Omet presses, which are manufactured in Italy. He says, “The penetration of digital motion control systems (of which servo motors are one component) into the narrow web marketplace in general is probably about 25 to 30 percent of all converters (meaning that 25 to 30 percent of all converters have one or more servo presses). The number is much less if you consider the overall number of presses in the marketplace compared with the number of servo presses. This covers the range of servo press designs from simple hybrid presses to more sophisticated gearless-shaftless-sleeve presses.”

Within the press manufacturing companies, the ratio of servo presses to non-servo presses sold has shifted significantly. Jakob Landberg, vice president of Nilpeter, Slagelse, Denmark, says that about 80 percent of all new presses manufactured and sold by the company now are driven by servos. David Baumann, product manager at Gallus, St. Gallen, Switzerland, reports that 60 percent of Gallus presses built today are hybrid (a combination of servo and gear) or fully servo.

Making the move


What is the attraction of servos? Are the conventional gear and shaft presses no longer doing the job? The answer to the latter is yes, they are, but a servo press can make a difference. Randy Duhaime is general manager of Dion Label Printing in Westfield, MA, USA, a company that recently took delivery of an MPS EFh410 16" eight color press manufactured by Multi Print Systems. Duhaime explains the company’s interest in switching to servo.


Print cylinder sleeve technology, shown here on an Aquaflex FPC press, is another benefit of servo technology.
“Servo is the only printing technology that we considered when researching a new flexographic press. This technology has progressed steadily and has proven to be a solid solution to the needs of growing label companies looking for the next level of quality and efficiency. We are always looking for means of improving efficiencies and building production capacity. We were confident that servo technology with full auto registration, full UV capability, faster changeover and higher press speeds will help us to reach these goals. In addition, we were interested in having the ability to print on thin unsupported films, including shrink film and pouching materials.”

The Dion team has been operating the press only for a few months, but results are favorable, Duhaime says. “Press production is meeting our expectations, but we need more experience to fully benefit from the higher speed and quick changeover. The registration capabilities have allowed us to reduce waste and print many jobs in four-color process even when reversing out small type from all colors.”

Dion Label is known in the industry for its dedication to environmentally sound practices. The servo press, Duhaime reports, contributes to that effort. “The reduction of both setup and running waste is key to our sustainability efforts. The UV inks are contributing to efficiency due to the elimination of daily cleanup. Our press also has a “Lean Inking” feature that eliminates the need for a metering roll and large ink pans.”

Press manufacturers agree on the benefits that a servo press can bring to the printing process.
“Hybrid motion control presses will improve the print registration and reduce waste compared with traditional geared presses,” says Leiben of Matik. “More sophisticated gearless-shaftless press designs provide exceptional print register, print quality and greatly reduce the waste to less than 2 percent. Further, gearless-shaftless presses provide unmatched repeatability and consistency from run to run, even compared with hybrid motion control presses. Gearless-shaftless technology also allows the integration of multiple printing technologies on a wide range of substrates, which is difficult if not impossible on hybrid motion control designs.”

“Servo technology enables a tighter register and eliminates most of the barmarking,” says Landberg of Nilpeter. “When I say ‘most of the barmarking’ I mean that in mechanical equipment there will always be some kind of mechanical transmission with potential worn out gears, etc. Outside of the improved printing results, the converter has vast savings potential in setup time and wasted material from setup. The servo system enables presetting, recalled process parameters, and much more.”

Rosenbaum of Aquaflex says, “A servo press improves the label by providing more consistent print registration throughout the job run. Servo presses reduce the materials waste associated with drifting registration and they require less maintenance. Production and print quality is improved, resulting in a healthier bottom line. Customers who invest in servo technology also enjoy quicker size changes and easier press operations.”

“The major benefit is the possibility to produce labels more efficiently and therefore cheaper: faster setup times, less waste, higher production speeds, more stable production, and much better register accuracy,” reports Baumann of Gallus. “Another important effect is the greater freedom of processible substrates. A modern servo press like the Gallus RCS is able to convert substrates from 12µ up to 450µ with almost no restrictions. The combination of single direct servo drives and intelligent software is able to adapt the machine to the various substrate properties, like elasticity, thickness, surface, material, etc. Just a few years ago it was impossible to print an eight-color job on 12µ monofoil.

“Besides the substrate flexibility, the process flexibility is an other obvious benefit. The exchange of a flexo printing head with a screen printing head can be done in only a few minutes on the Gallus RCS. Therefore the degree of decoration and the freedom in reproducing complicated designs is much higher than in the past, and will increase further.”

A variety of configurations


Servo motors replace shafts and gears by connecting directly to a cylinder and controlling only that cylinder. They receive commands from a central processor. Some or all of the cylinders on a press can be driven by servos. Manufacturers vary in the configurations that they create.

“On Nilpeter’s flexo servo presses, all printing cylinders/sleeves, as well as impression cylinders, are servo driven. On the offset machines, the plate cylinder, blanket cylinder, impression cylinder, inking cylinders, and dampening cylinders are servo driven. Also, the functions that move the cylinders in and out of impression are servo operated. In short, most moving parts are somehow operated by servos,” says Landberg.

At Mark Andy, “All of the servo presses have servo driven infeed and outfeed tension controls, as well as servo driven die tooling and rewinds. The biggest variation in servo implementation occurs in the print stations. The 2200 Servo press has one servo motor per print head. The XP5000 and the Comco C1 feature dual axis servo implementation, meaning that the impression cylinder and plate cylinder are driven independently. The Comco C2 has multi-axis servo implementation – up to nine servo motors per print head. These can drive the impression cylinder, anilox roll, plate mandrel, and chill roll, as well as positions for ink to plate and impression setting.”


A print station on the Omet X-Flex servo press
“100 percent of Omet narrow web presses use digital motion control drive systems,  from 10" to 33",” says Steve Leibin. “Omet has incorporated digital motion control technology into areas of the press other than just the press drive system. The company has a servo driven diecutting system, the Twin-Cut, and a servo driven sheeter, the Flying-Cut, both of which utilize digital motion control technology to eliminate changing tooling for size changes when diecutting and sheeting. Omet also uses digital motion control  technology in its Holo-Foil King hologram hot foil unit to independently register each stream (up to 6 streams) of hot foil across the web.”

Questions


Servo technology also seems to bring out the philospher in some press manufacturers. Eric Hoendervangers, managing director of MPS, Didam, Netherlands, which manufactures only servo presses, challenges the description of “servo press.”

“What is a servo press? What is the definition of a servo press? Twenty years ago you could buy an eight color flexo press from one manufacturer for $300,000, and an eight-color flexo press from another company for $1 million dollars. Both of those companies now have servo presses. Which do you buy? If a company all of a sudden puts servos on a press, is it a good press? We see so many solutions, even with the big players. Everybody is now servo, but still there is a huge difference in the press manufacturer’s philosophy. For example, it is like the difference between cars. Years ago, no cars had airbags. Today they all have airbags. Are they now all the same? Today people think that adding a servo makes all the presses identical. That’s not so.

“We are strong believers in developing ‘technology with respect.’ Some people really exaggerate, and put servos all over the place. Our practice is to put them only where you need them. We have several different options, limited or completely servo. The customer needs to understand the differences in press builds and company philosophies. He really has to study, do print trials, look at waste figures, print quality and ease of operation, and buy the one he likes the best. If they are all the same, buy the cheapest one.”

Federico d’Annunzio is managing director of GIDUE, an Italian press manufacturer that has fallen on hard times quite recently (see Industry News, page 8). Still, he remains active in the industry and plans to continue focusing on the narrow web market. D’Annunzio confesses to having mixed feelings about servo power.

“To be sincere, I am confused about what is going to happen,” he says. “On one side I can see a lot of advantages introduced by servo technology. On the other side I have problems justifying the return on investment with the use of servo technology. I think the economics should drive the investment. Servo presses have a lot of advantages, but you have to use all of them to pay back the major investment. That is the key factor in the coming months.

“If you are just making plain labels, and the price ratio is 2:1, it is not really justified, because the registration capabilities now on mechanical presses is perfect. But when you need a press for delam/relam and a lot of job changeovers, then you are justified. The advantage of a servo press is in the preparation of the machine: You have to have many job changes to justify the investment. The difference is a question of 10 minutes, less or more, in terms of setup, and maybe 30 to 50 meters of waste. If you have only two job changes per shift, it’s not justified. If you go four to six, a servo machine will do.

“It doesn’t achieve better quality in the printing of labels, or better registration. That’s not the point anymore. It helps only in the automation of the presetting of the machine.

“Also, we should evaluate whether the technology adds value to the industry. Is it really creating more profit for label printers? Is anything really making more profit for the label printers? Are all the technologies that we have developed in the past 10 years creating profit? Did the press industry really create added value for the converter, or did the converter create the value with his own organization, his own creativity, and consider the press as a commodity? These are questions that have to be considered. The economic crisis forces us to put questions on the table about how we do business.”


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