Cover Story
IS OFFSET THE MAGIC BULLET? In short: it comes close! As we are all aware there is no real world in which magic bullets exist. Gravure has excellent strength in metallics inks, flexo has best capabilities of heavy laydown in coating, e.g. in a last down white for reverse printing. For these reasons in most cases offset is configured as a hybrid print process using gravure or flexo decks incorporated in-line to the colours printed in offset.
Just to demonstrate a striking example: the same opacity in EB white requires three times less ink compared to a solvent-based white and a water-based white laydown. The demonstrable costs for an expensive EB flexo coated opacity are lower compared to solvent-based white. So, the essence of sleeve offset is the joined force of in-line hybrid printing with in-line station decks combining 6 or 7 colour ECG printing in offset with gravure and flexo decks. Operational energy consumption on average is 65% lower in contrast to traditional solvent-based printing and no VOC’s or solvents have to be incinerated. As with any real-world technology, packaging printing in Offset has drawbacks. Printing ‘gapless’ in offset is not possible, as imaging in the round is currently not available in the market. The alternative solution to that is called ‘staggered plate’ where a randomly shaped gap offers a solution to such constraint.
Probably the most dominant hurdle is the initial capital expenditure being relatively high. Nonetheless, it can be demonstrated with verifiable and ‘hard’ calculations that offset is always more cost-effective than solvent-based printing.
The main reason is not only the figurative cheap offset plates of less than €10 apiece, readily imaged and accurately mounted in a minute without tape. Another important reason is that in ECG printing fewer colours are required; so less ink, less cylinder engraving, and less make-ready waste, as all data is retrievable as a setting with consistent colour performance.
The second drawback is more human-related. The difficulties gravure printers may encounter when migrating their press operators, pre-press staff and salespeople to offset is frequently experienced. It takes a learning curve to entrust the offset machine pre-press technology and step back from spot colours to a 7 colour ECG process. Acknowledgement of the need for a training
program to absorb the technology will help to shorten the learning period.
There might be presses that can match offset print performance in certain areas, but it is the unique combination of these areas together that make offset stand out from its competition.
THE BUSINESS CASE
Apart from its unparalleled sustainable performance, the key factor when deciding on offset is the cost-benefit that comes with the process. Supporting the cost-benefits, a part of the detailed comparing calculation between Rotogravure, CI flexo solvent-based and sleeve offset is demonstrated below. These calculations can be shared in detail for verification purposes. The business case is based on:
O a 15.000 m² print job at a 250 m/min production speed
O eight colour gravure and flexo, vs 6 colour required in offset
O a €2.000.000 high-end gravure and CI flexo press, vs a €4.000.000 EB-offset press
O reverse printed with 35% ink coverage per print unit and 80% last down white coverage.
To better understand the cost benefits of each printing technology, we compared the cost benefits based on the length of the print job in the chart above.
DECARBONISING PRINT In this business case, cost/m² and CO2
balance are calculated. Offset printing generates 75% less CO2 and is
about three Euro cents /m² cheaper, offering supreme quality.
Even when it comes to larger print jobs, DG-AUXO still performs better than flexo and gravure. Only from print jobs of more than 40.000m² flexo and gravure start closing the gap. Because gravure and flexo both have higher origination and cylinder costs, making it expensive to start, only on larger print jobs the costs start levelling out.
We can say that tomorrow’s sagacious flexible packaging printers will be technologically agile. They must be able to adapt their printing infrastructure in the future to meet fast-changing markets and environmental constraints.
It is for these reasons that the leading packaging printers engaged in both gravure and flexo need to look at the new option of offset with EB curing. Can they afford not to look at this?
Can offset dethrone solvent-based ink systems in the printing industry, and effectively decarbonise flexible packaging?
Xwww.dgpressservices.com
emission
Annual GHG per 40.0000.000 m2
print run for each machine.
www.convertermag.com
April 2022
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