High-speed rotogravure printing

Photo | Bosch Rexroth AG
Marginal Column

Above: Quicker to the market: Installation of the Aurora rotogravure line, featuring a shaftless automation concept.

Illustration | Bosch Rexroth AG

Infograph: Advantages of the Aurora

With the “Aurora” series of rotogravure presses its manufacturer, Cerutti, rings in the start of the modular age for magazine and catalog printing.

 

In spite of the spread of digital media, print still has great potential. Competitive pressure in the industry is, however, enormous. Those who wish to survive will have to make their mark with innovative and efficient solutions. This is true above all for the manufacturers of printing presses. With its Aurora series the company Officine Meccaniche Giovanni (O.M.G.) Cerutti has introduced a successful concept for a rotogravure press line intended for use above all in upscale magazine and catalog printing.

This Italian manufacturer of gravure presses is counting on an automation solution from Bosch Rexroth that does away with shafts entirely, thus reducing the time to market by one third. Consequently the time that elapsed to Cerutti’s delivery of the first press to the Grupo Abril media group in Brazil was just 12 months instead of 18.

A new approach

In the past the machine’s components were synchronized by way of shafts and gearing. This system suffers serious disadvantages. The mechanical components are subject to wear and setting up a new job is time-consuming. And to test its functionality it was also necessary to assemble and disassemble the press in the manufacturer’s plant before it could be dispatched to the customer’s site, where it was assembled once again. This drove up project costs and stretched out delivery times. What was Cerutti looking for? A solution that would save costs, time and re-sources. It ultimately decided on a modular design for the press.

The idea was to synchronize the printing units electronically. A central control unit coordinates the individual drives that move the printing cylinders and the web. The challenge for this shaftless technology is to be found in exact and fast real-time communications between the controls and the individual modules.

An experienced partner

This shaftless technology was developed by Bosch Rexroth in cooperation with manufacturers of roll-fed presses. This design principle has been used successfully for almost twenty years now. It lets machinery manufacturers set up more flexible and more productive concepts and do so faster and at lower costs. “Subdividing the line into independent modules that we can assemble and test individually was our first choice,” emphasizes Italo Busto, project manager at O.M.G. Cerutti. It is now possible to produce printing units and modules in large numbers and assemble them at the customer’s printing plant. Users can even insert additional stations in the press line at a later date.

Control of this high-performance machine is handled by the IndraMotion system solution. As far as the drives go, Cerutti uses the closely scalable product line with servo drives, linear technology, and hydraulic and pneumatic power. The precise interplay of these components is complex but easy to control, thanks to a new operating concept. Printers can make adjustments at ten command terminals and check the results at once. “This is one reason why those who use Aurora can get along with about 25 percent less staff,” Busto stresses. Setup time for a new print job is also shortened to just an hour.

Fast and efficient

But that’s not all! The amount of spoilage was reduced by as much as 40 percent and production outages by 50 percent. The press continues to run at full speed even while the paper rolls are being changed. And that is quite impressive. At 51,000 revolutions per hour the Aurora prints 900 pages per second. That represents a 21 percent boost in output. In spite of all this, the press uses 12 percent less energy than those with mechanical synchronization. The comprehensive system behind Rexroth 4EE (Rexroth for Energy Efficiency) makes this possible. It begins right with the engineering design for the press and uses simulation models to consistently avoid over-dimensioning. Efficient products and systems and reclaiming previously unused energies through recovery and storage complement the package of actions taken here.

That was convincing enough for the printing industry and Cerutti was able to install yet another two machines in less than one year from the start-up of the prototype. Thanks to this new concept, another printing company is ahead of the competition by a nose.