Sustainability and cost efficiency in packaging gravure
von Ansgar Wessendorf,
Bobst's latest gravure press, the Expert RS 6003, was launched in September 2020
(Quelle: Bobst)
(Photo Credit: CORDERA STUDIO)
New technologies and their rapid development are often the focus of media attention and attract the interest of those in the industry. As a result, a tried and tested process such as packaging gravure, suddenly finds itself being viewed as tired and not particularly innovative, despite remaining the undisputed leader in terms of print quality and consistency. Bobst of Switzerland with its solutions that focus on the use of technologies that are both cost effective and that ensure sustainable operation, shows that this is far from being the case.
Not only do packaging gravure printers have to fulfil high printing and inline finishing demands, but they also need to demonstrate to their customers and the public that they are producing sustainably.
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In addition, they also need to fulfil the brand owners need to deliver “cross” packaging applications on multiple substrates with accurate color matching requirements. All this requires smart concepts that can be configured to meet specific customers’ requirements.
oneECG brings gravure into the digital world
Global color consistency is a conformity that brand owners aim to achieve on a global scale, therefore, to deliver on this request printers and packaging converters have been increasingly adopting the Extended Color Gamut (ECG) technology across different printing methods. Gravure was left lagging behind until Bobst deployed its oneECG technology to gravure printing earlier this year.
Bobst’s oneECG for gravure printing presses is an open-partnership system to multiple suppliers, developed for use with solvent-based and water-based inks. The partners along the value chain collaborate to achieve the highest color stability, repeatability and consistency and are certified to ensure quality of results on Bobst gravure ECG ready presses. In addition to the 100% repeatability of color consistency and print job quality, oneECG printing meets many sustainability and higher efficiency objectives on a number of levels: it enables immediate digitalized color matching (depending on software/hardware installed and machine configuration), it saves inks and labor time as there is no need to change colors in the print units at job changeovers, and there are less parts to be cleaned; it makes print cycles more agile, even for shorter print runs, with greatly reduced time to market; it requires less cylinders and Pantone color in stock; and also affords the possibility to make a series of job variants share the same engraved print cylinders. The technology is not only available on Bobst new machines but is retrofittable on installed gravure presses.
What does Bobst offer for gravure presses
Bobst is an undisputed leader in the gravure press sector not only in terms of sales figures but for its very varied and broadly based product portfolio. Customers can choose between six different models for packaging printing alone, and Bobst Italia also offers a range of three press types in the “Special Applications” sector which includes printing and inline finishing of decorations, liquid packaging, cigarette packaging and folding boxes. All nine gravure presses are basic models or platforms and can be specifically configured as desired to suit the customer’s particular requirement profile. Since al gravure presses are inline designs the addition or insertion of additional units or assemblies for inline converting steps such as laminating, cold seal coating, embossing and die-cutting is relatively simple. As a result, no two Bobst gravure presses are identical, since in most cases they are tailor-made systems and each one is unique. One of the advantages of Bobst gravure technology is therefore its extensive choice of different press types and configuration options.
The Twin Trolley concept allows the complete change of the trolley with gravure cylinder and ink supply, as well as the separate change of gravure cylinders without ink change (Quelle: Bobst) (Bild: CORDERA STUDIO)
Waste reduction has long been a focus for Bobst’s R&D, and this is particularly significant when considered in conjunction with run length in gravure printing. Short make-ready times and the lowest possible wastage rate are always important, but they are especially so when very different jobs need to printed cost-efficiently, just-in-time and in small batch sizes.
In this respect, Bobst latest gravure press the Expert RS 6003, launched in September 2020, makes a perfect fit to enable converters to tackle today’s market challenges: increasingly smaller batches, versioning, thinner and lighter substrates, ready to recycle packaging, global color consistency, production agility and sustainable operation.
Al in the press is aimed at optimizing sustainable operation: the design is very compact – 25 m L x 5m H for and 8-color press, making it easy to fit different factory layouts. The short web path – around 100 m for an 8-c press – is possible thanks to the new drying chambers that generate 30% less waste than conventional design at start-up and changeovers due to the shorter hood length, that, however, deliver comparable drying efficiency.
The press handles high-speed printing with both solvent and water-based ink printing. It is oneECG-ready, which means fast digitalized color matching, achievement of a color gamut larger than the traditional CMKY, and further energy savings as the process requires less drying capacity for the full color mid machine.
Another exclusive feature of the Expert RS 6003 is the Flex Trolley that simplifies and speeds up job preparation and changeovers. It is a service-type trolley that can either remain on-board or be removed from the unit after set-up. Most conveniently it offers the possibility to change only the print cylinder or the complete trolley carrying the inking units, the print cylinder, the splash guards and the ink tank.
For its gravure presses, Bobst offers fully automatic and manual trolley changing systems: its Twin Trolley, a feature of the Master RS 6003, really stands out from the crowd in terms of waste reduction. Here too, the concept allows both a full swap of the trolley with gravure cylinder and inks supply or the swapping of just the print cylinder. The advantage is that CMYK process inks can be left permanently in the press. The following example puts into figures the possible savings from the use if a Twin Trolly compared to a conventional one. According to Bobst, if a 9-color gravure press runs 275 days/year and an average of five jobs/day are made ready, then the annual savings in ink, solvents and distillation costs run to about 60,000 Euros. The time saved in cleaning single color components and ink adjustment is reported to be about 1236 hours/year.
Stable print register
Bobst can point to considerable success in relation to register control on gravure presses, beginning with the first integration of an electronic drive shaft with Registron register control system. The TAPS system (Total Automatic Pre-register Setting) for fully automatic pre-registration was a further milestone.
The registron register system on a Bobst gravure press (Quelle: Bobst)
This allows the register for all press units to be pre-set in just four minutes and at the touch of a button, regardless whether it is aa new or a repeat job. The cylinders are first automatically turned to the register position and then the printed register marks on the web are scanned by Registron, corrected and monitored. The TAPS system also makes a crucial contribution towards ensuring that the total amount of substrate waste during make-ready is <15m per print unit. Today, Bobst fits the TAPS system to all gravure presses for flexible materials.
Summary
As a result of constant enhancements, gravure printing at Bobst continues to maintain its high technical standards and remain the benchmark when it comes to equipment efficiency. Bobst Connect – connectivity, being one of cornerstones of Bobst vision along with automation, digitalization and sustainability – can add new capabilities to the press performance with digital solutions for pre-press, production, maintenance and overall optimization. oneECG gravure new process developments is poised to give a powerful impulse to the re-establishment of gravure as a printing technology capable of truly major innovations. This, in combination with its stable, high print quality will be determinant in making gravure play a renewed role in packaging printing into the future.
