Rotogravure cylinders: review on alternative coatings to copper

0

Rossini SpA’s Ecograv research program has entered the final phase of development. The replacement of the copper and chrome galvanic coatings of rotogravure cylinders with a single layer of technopolymer is now a reality.

It is applied directly to the steel surface of the cylinder, ready to be electro-mechanically ground and engraved and then made immediately available for printing, without further coatings or treatments. We are talking about Ecograv: the new technology developed by Rossini SpA as an alternative to the traditional copper and chrome coating of cylinders for roto printing.

The development program has now entered into full swing with printing trials on industrial rotogravure presses. In this important phase of work, Rossini is collaborating with an expert Italian engraver, two important European OEMs and two well-known Italian converters. The activities are in full swing and the results are encouraging: they have been confirmed by the tests carried out in recent months at the Rossini Technology Center, where it has been possible to print, using the same printing cylinder and without any problem, about 1,000,000 linear meters of product.

Resistance and calibration: the industrial tests

The durability tests carried out at the OEM’s premises confirmed the polymer’s resistance: even after 300,000 linear meters of printed material under standard production conditions (inks, solvents, doctor blades, etc.) at speeds of 350-400 m/min, the polymer of the cylinders showed no signs of wear. Converters who used Ecograv cylinders to make commercial production batches on plastic film and aluminum laminates also found the same result.

These tests also made it possible to make further progress on the calibration of the engraving curves of the cylinders, still under study, in relation to the different degree of ink transfer from the engraved cells onto the polymer layer. In fact, from the beginning, all printing tests have shown a release capacity far superior to the cells engraved on copper. This behavior represents a clear advantage for colors with low coverage, as it guarantees to reach a higher printing definition than traditional cylinders, adapting the engraving parameters of the cells. Of course, the results of the next works will allow to further and progressively refine the engraving curves of the new printing cylinders that will be used in subsequent tests.

While the work taken by printers and converters continues, in the Equipment Rossini plant the complete Ecograv line is under construction, which carries out all the steps of the production of the new cylinders and will be exhibited at the beginning of 2022 in the Rossini Show Room, at the printers’ disposal.

Commenti disabilitati