Rako increases rotary screen imaging productivity with Stork

The continued growth in demand for rotary screen effects has led self-adhesive label manufacturer Rako Etiketten, of Witzhave, Germany, to install a second Stork RotaLEN 5511 direct laser engraver, for its nickel screen cylinder imaging operations.

The new engraver, developed by Stork Prints Austria, has been specially adapted to provide a fast means of imaging both RotaPlate screen meshes, which run on non-Stork systems, as well as re-engraveable RotaMesh screens, which the machine is normally designed for.

Stork Prints’ account manager Ger Roza explained: ‘This special hybrid edition of the rotary screen engraver accommodates both a magnetic drum for the RotaPlate, as well as brackets, which are used to engrave RotaMesh. The Rako team originally began imaging RotaPlate by conventional exposure. Because of the sharp increase in consumption of the screen, this method became ineffective. Now, with the increased productivity of the new rotaLEN laser engraver, they will be perfectly able to maintain a smooth and flexible workflow.’

At under 20kg, the engraver’s magnetic drum is light enough to be safely handled by one person, and is suited for all mesh sizes. Furthermore, the system’s quick shaft system for easy drum / bracket insertion and release allows changeovers between screen types in less than 10 minutes. The drum’s magnetic force is also extremely high, to maintain stability at rotation speeds, which can reach up to 1600 revolutions per minute.

Since adopting the RotaPlate non-woven screen format, Rako has enjoyed high productivity and smooth production runs, without stoppages. The mesh’s good handling properties make it easy to reuse in the case of repeat jobs. This often leads to life-spans of above 50,000 meters. As a result of these benefits, the German label-maker has increased RotaPlate consumption to about 2,500 linear meters or 6,000 screens per year.

The new RotaLEN will also be able to reduce the workload of the existing RotaLEN engraver, which, till now, has been responsible for all of Rako’s RotaMesh imaging requirements since its October 2006 installation. Because of the growing demand for high value effects uniquely possible by rotary screen, such as embossing and raised varnishes, the first engraver is reaching full capacity, and is carrying out as many as 1,100 jobs per month. The company runs 35 RotaMesh-compatible RSI (Rotary Screen Integration) modules on 20 printing presses at its factory.

Towards the second half of the year, Rako intends to modify the original engraver, making it similarly compatible with both screen types. The company renovating its pre-press facilities, to best accommodate the new machine.

Direct laser engraving is a fully digital means of imaging relief and nickel rotary screen printing formes. In the case of rotary screens, it involves the thermal decomposition of emulsion covering the positive area, leaving behind the stencil’s open areas. The process eliminates the need for exposure, washing and drying, and the use of consumables such as film, chemicals and UV-light.

Stefan Behrens, Rako Etiketten’s pre-press manager, commented: ‘The RotaLEN and the direct laser engraving process have brought us greatly improved productivity levels, a much simplified workflow and perfect quality consistency. Screen cylinders are engraved at up to five times the speed of conventional exposure, and defects have been virtually eliminated. The second laser engraver, with its dual-format capabilities, gives us full job scheduling flexibility and the freedom to increase output yet further.’