Combo Printing's Final Frontiers
Will combination presses boldly go where relatively few have gone before?
by Jessica Millward, Associate Editor
THOUGH COMBINATION PROCESS is now and will continue to be a strong contender in the package print market, that strength, at present, is concentrated in narrow-web applications, and configurations most commonly involving flexo/screen pairings. While machines outside this perimeter have been built, they are relatively rare. Here, suppliers summarize combo print possibilities for not-so-fully explored worlds.
New World: Wider webs/CI formats
Today's platform combo presses afford printers a considerable luxury: choice. The combo press's ability to print using different methods, in whatever order necessary, means the printer can now "buy based on flexibility," according to Eric Short, president of RDP Marathon.
For example, Tom Kirtz, president of Telstar Engineering—which custom-builds combination printing presses—recalls creating a custom converting machine with die stations, laminating, diecutting, and sheeting capacities several years ago. Recently, the same customer asked Telstar to add UV screen and UV flexo print capability to the machine. The all-in-one solution, with its ability to adapt to future requirements, is a strong lure to a market facing shorter runs.
Such flexibility has historically been limited to under-24˝ webs, says Gallus Sales Manager Bob Yates, because of run speed concerns. For example, he says, "Combination process printing is not for wide-web flexible packaging, which a printer would want to run at higher speeds."
Another major factor in the development of wide-web combo presses is waste control. As Dick Chesnut, president of W.R. Chesnut Engineering points out, "Combination presses have a tendency to produce more start-up waste and running waste than conventional presses, particularly with offset and letterpress, where ink keys need to be individually adjusted for each color station." Because narrow-web presses are typically better at conserving waste, he concludes, combination applications have flourished there.
Challenges surrounding central impression combination formats involve both technology and economics issues. Nilpeter Director of Engineering Richard Powell explains because the drum on the CI press acts as the impression cylinder, while stations revolve around it, it is quite difficult to move and interchange process cassettes. Short also cites the problem of dryers on a CI press—there simply isn't enough space between print stations for them.
A combination CI press probably won't be market-feasible at any point in the near future, contends Ko-Pack International Sales Director Gerry Nigg, "simply because the cost is going to be so prohibitive."
New World: Gravure
While there are no disputes about the quality of gravure print, the pairing of the process with others on modern, platform combination presses is not a common occurrence today.
Yates remarks on the exceptional metallics and fluorescents produced by gravure, often found on detergent and spray bottle labels, but does count an additional issue with gravure capability on a combination press. He states, "Highly volatile inks require explosion-proof presses," which, in turn, involves different wiring, high-velocity gas dryers, and other factors. Powell agrees: "This has caused many press manufacturers who do not want to deal with these safety issues to back away from offering this process."
The use of a gravure unit in a platform-type machine is not so common today, says Chesnut; however, the basic gravure press with units such as screen and/or UV flexo is a popular item for labels on consumable products.
Evolution of the gravure process may propel it further into the combination print configuration. Powell asserts, "Increased use of hot foils for product applications has spurred the printer's desire to use the high-quality metallic inks and the high-speed laydown gravure provides." He also believes the development of water-based and UV inks, as well as plate cylinders, for gravure, will make it an attractive option for press manufacturers and printers alike.