Sustainability of the planet will continue to be a significant issue for printers and converters.
Not only do brands mandate accommodation but by most accounts, it is the right thing to do. The objectives list out in obvious measures: less waste, less ink, less energy, less CO2 expended. As energy has become an even more crucial commodity, flexographic press manufacturers have been adding features to optimize energy consumption wherever they can.
For brands, this goes far beyond printing and into, for example, transportation, consumables and packaging recycling. This puts pressures on the manufacturers of the substrates and inks, as well as press designers and engineers charged with making the sustainable-minded consumables print well on press. To that end, press manufacturers are doing all they can to handle all environmentally friendly technologies such as water-based printing, paper or biodegradable materials printing, expanded gamut (EG) printing or energy-cured inks (UV).
Press manufactures commonly deploy a two-pronged approach in meeting the challenge and demand:
- Assure successful ways to print attractive graphics on difficult substrates
- Offer ways that operation of the press itself puts less strain on waste and energy requirements
Innovative Substrates
Packagers and more importantly, brand owners, are always looking for new materials that are easier to work with, and substrates and inks that are safe—for food products, in particular.
All photos courtesy of SOMA
There is an influx of new materials that assures packaging is fully recyclable, or reduces the carbon footprint, while not impacting product quality or the appearance of the packaging.
An effort to offer various barrier coatings to replace laminates, applied either on press, in a downstream unit or at a separate station, is also well underway. From a basic brand’s interests, it complies easily with food safety standards, while allowing 100 percent recyclability of the packaging. Manufacturers of these new substrates are trying hard to assure that anything they develop can be fully useable on current packaging equipment.
Ink Systems
With new substrates and a trend away from harmful materials, there is a movement away from solvent-based inks, with many more preparations of water-based inks. In fact, in its 2022 report The Future of Water-Based vs. Solvent Printing to 2027, Smithers projected aqueous inks to grow 5.6 percent annually through 2027, compared to solvent ink growth of 1.3 percent. (See FLEXO’s February 2023 issue).
Another sustainable solution is UV LED ink. It is a volatile organic compound (VOC) emission-free process, with no ozone extraction required, resulting in reduced infrastructure exhaust systems, air exchange and power delivery. Moreover, UV LED ink makes design graphics pop out from the package. Higher ink pigmentation also means less ink volume is required.
For solvent- and water-based inks, one way to assure that slow-drying inks are dried as efficiently, and as fast, as possible is to create “intelligent drying.” If you can create an almost closed-loop drying system, you can dry inks efficiently. Only when it reaches the defined lower explosive limit (LEL) level (solvent saturation in the exhaust), will the system output a minimum amount of air (and energy) needed to drop the LEL level to a defined point.
An effective system can automatically adjust the speed of ventilators and/or keep them on a minimum level during stand-by mode. A multi-fan drying system consisting of a between-deck drying loop and drying tunnel loop can help to dry ink quickly. It can also deliver exceptional energy savings via integrated heat recuperation from a regenerative thermal oxidizer (RTO). From burned fumes, energy is recovered and used to preheat the air-drying systems in the press.
EG Printing
EG printing has become a hot topic and a number of companies offer solutions. When it comes to expanded color gamut economics, the resulting environmental impact is just as important as the aesthetic advantages.
By avoiding ink changes between runs, a printer can reduce wasted ink and washing detergents. This results in a more ecological package printing process with more run time, less setup time, less cleaning and less waste. Ink inventories are reduced because there is less need to store expensive spot colors. It also means no anilox change, reduced usage of solvents for washing the press, and the ability to print multiple jobs on the same run. Furthermore, gang-run printing allows high flexibility to print short jobs more ecologically and efficiently.
Press Makeready
If you can prepare the next job while the previous one is still running, you have a leg up on time and reducing waste. Some systems measure data used for makereadies on the press, during the plate mounting procedure. An intelligent register and impression setting system then offers printers a powerful solution for short runs.
When a sleeve is inserted into a flexographic press, registration and topography/impression data is read from a RFID chip and prepared for fully automatic operation. It helps to assure that every job is automatically in registration and impression quickly.
This reduces makeready time and assures faster completion of jobs—along with almost zero-meter setup waste—a flexible, agile and sustainable solution for short runs. Don’t forget color management for conventional CMYK + spot color printing. A good color management and/or matching solution will allow printers to reduce makereadies as much as 25 percent, increasing capacity, saving ink and reducing waste.
Sustainable Features
There are many more features that every press manufacturer can offer to make a company more sustainable. Here are a few that can add up:
- Improved insulation: By maintaining temperatures in the deck and tunnel drying, the press is made more efficient
- Press monitoring system: An advanced, modern press monitoring system can allow supervision and long-term monitoring of flexographic press efficiency and energy consumption via the internet, from the office or anywhere in the world. This can have as much influence as any mechanical improvement
- Energy recovery: Installing the latest, most efficient drives—some of which can include electricity retrieval—can reduce the amount of power required to operate the press. With a recuperation system, the kinetic energy—the total random moving energy—can be converted into useful electrical energy. It may not be too extensive, but it is measurable and helpful
- Gas/electric hybrid drying systems: The operator can make a decision based upon energy costs at any given time. While they run separately, both systems are installed, and the operator chooses, on a panel, which will operate during printing
- Ink cartridge system: Certain inks can be expensive—and it is always a shame to waste any ink. Some ink cartridge systems can reduce ink volumes and residual waste. On average, about five to seven liters of ink are in the press system in one deck (doctor blade chamber, pump, hose, etc.). When a print job is finished, this ink is returned to a bucket, yet some percentage of the ink is always lost on its way back, due to cleaning or residue. With an efficient ink cartridge, only a minimum of 1.5 liters (maximum up to 4.5 liters) is ever in the system. Therefore, ink losses are much less
What should we expect? What could happen in the future? A greater environmental approach in packaging is guaranteed. One option is bio-renewable packaging. The second option is 100 percent recyclable packaging. It seems that the path is not defined yet, as both technologies have their pros and cons. Yet, surely, there will be new printing challenges associated with this.
It all starts with the press.
A flexographic press is still the heart of a print facility. Any way that it can be improved to save inks and substrates, print exquisite graphics with sustainable materials, and be energy efficient is advantageous. It makes a company more attractive to a brand owner, safer to its employees and more cost effective.
Most important, it provides the company with an ethical standing on this Earth. Pay attention to what your flexographic press can do.
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