Pressroom Productivity with Direct Laser Engraving
Flat plates have traditionally dominated the North American flexography market. Even in the last several years, the limited amount of cantilevered presses, the long lead time for sleeves and the perceived high cost have hampered adoption. Printers are now demanding ITR technology for several reasons, the most immediate of which is efficiency.
ITR sleeves require no plate mounting stations, mounting material or labor. This allows for quicker makeready. When mounted, digitally engraved sleeves are aligned to each other during engraving (using notches) for perfect registration. This leads to considerable savings on labor, substrates and ink when getting up to color. With fewer variables and a more uniform printing surface, press speeds can be increased beyond what is capable with flat plates. Short run and repeat jobs can be changed out quickly, and the increased durability of elastomer sleeves allows for longer printruns.
Since there are fewer things that can go wrong with sleeves during the printing process—like undetected flat plate mounting issues, plate lift, cylinder bounce, lack of uniformity, etc.—ITR can help eliminate variables that lead to problems during printruns and cause press downtime. While individual elastomer sleeves may be more expensive than plates, increased productivity, combined with the elimination of redundant plates, can actually lead to an overall cost savings over flat plates.
The uniformity, consistency and registration of sleeves, combined with the ink transference, density and resolution of digitally engraved elastomers, allow for faster printing speeds with superior quality. This allows printers to leverage new technologies to achieve ROI now instead of later.
The Benefits of a Digital Workflow
A direct laser engraving workflow involves fewer stages, reducing the possibility of error. By eliminating steps and variables, we are eliminating failure points, thus making the process more consistent. With this process, there is no essential ablation mask as with direct photopolymer laser imaging.
Direct laser engraving plates and sleeves are produced in a two-step process. First, the non-printing areas are removed with a high-power laser imaging system. A short, water-and-soap-based cleaning detergent wash-and-dry cycle follows, which is a lot less involved than the post-processing stages for direct laser imaging or conventional flexo plate making using photopolymer plates. Additionally, photopolymer washing stages can often involve solvents harmful to workers and the environment; laser engraving eliminates this. As sustainability becomes more important to printers and brands, it’s essential to know that, from an ecological point of view, there are no issues to be concerned of with volatile organic compounds (VOC). The production of direct laser engraving printing forms is completely free of solvent. Following that, the printing form is ready to go on press.
The involvement of only two pieces of equipment and a true digital output is especially appealing because the need for floor space is greatly reduced. Taking a look into the future, it is fair to say flexo printing form production will most likely move more toward the printers, much as it did in the offset realm years ago. Data could be sent straight to the printer, eliminating the shipment of plates. Remakes are done quickly, with no auxiliary equipment needed.
The Future of Direct Laser Engraving
After this very broad overview of direct laser engraving basics, one question comes to mind: If direct laser engraving is such an advanced technology offering this many benefits, why is it not more popular? There is no simple answer to that.
Direct laser engraving is facing the same issues as any other new technology, such as digital plate making did in the beginning. These issues include slower production speeds, machine and plate availability, initial investment and so on. Just like in those days, development has to take place in order to accommodate the market needs. However, over the last three years, a lot of progress has been made. Engraving speeds have already doubled and faster materials are now available.
Let’s look at direct laser engraving’s potential in specific markets:
- Label printing: As label printers lean more and more toward UV inks, this will be one of the growth sectors for direct laser engraving technology. The smaller plate sizes, in combination with the material properties of the elastomer plates, will offer quite a few benefits when it comes to printing labels
- Flexible packaging: With increasing production speeds, compressible plates that do not need cushion tape, coupled with all of the other benefits of elastomer compounds, the flexible packaging section of the flexo market has become increasingly accepting of laser-engraved elastomer printing forms. Faster press speeds and less “dirtying up” allow for more press uptime, adding to a significant cost savings
- Corrugated printing: Pre-mounted, laser-engraved elastomer plates will result in an increase in print quality for corrugated. Eliminating registration issues and time-consuming mounting processes will attract corrugated printers to direct laser engraving. An increase in imaging speeds made possible with technologically improved engraving units with dual heads and four beams will make direct laser engraving even more appealing to this market sector
- Specialty packaging: Dry offset printing (indirect flexo) for cups and cans has been lacking print quality due to the limitations of traditional plates, losing market share to IML (in-mold labeling), heat transfer and digital. Using direct laser engraving technology in this segment will certainly boost print quality, due to higher ink densities, higher linescreens and smoother vignettes (through the use of sub-surface dots in highlights). This segment is a classical UV ink application where elastomer’s natural material properties excel
- Printed electronics: As this application becomes more mainstream, direct laser engraving plates will play a large role. With rotary screens being costly and limited in fine line detail, elastomer plates can provide a medium that will retain the intricacies while resisting the effects of abrasive inks and harsh solvents
In Conclusion
The benefits of direct laser engraving will continue to grow as the technology evolves. Faster lasers and improved elastomers will further drive printers to the direct laser engraving process. The ecological advantages of direct laser engraving, driven by brands and end users, may also determine how plates and sleeves will be produced.
About the Authors: Brendan Pollard is managing director at Applied Laser Engineering Ltd. Armin Senne is business manager, flexo at ContiTech. Adam Smrdel is director of flexography at Carey Color Inc.