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

Label & Narrow Web, Jan-Feb, 2009 by Jack Kenny

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 12[micro] up to 450[micro] 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 12[micro] 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."

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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.