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FLEXO Magazine : November 2009
44 FLEXO NOVEMBER 2009 www.flexography.org Between late-night infomercials hawking work-at-home schemes, calls from stock brokers, and emails from supposed relatives of foreign dictators who offer you millions of dollars for your assistance with financial matters, people have become inundated with tales of easy riches and have learned to disregard them. So it is with trepidation that I mention the results of a study that shows how even an operator of a three-color, 23in. press can save about $57,000 per year. The study in question is from the U.S. Environmental Protection Agency's (EPA) Design for the Environment (DfE) group. In partnership with Western Michigan University, The University of Tennessee's Center for Clean Products, and the Gravure Association of America, they produced research summarized in the report, "The Effect of Ink Temperature on Solvent Losses and Print Quality " in February 2001 (Report #EPA744-F-01-001, available from the EPA's Web site). Though the research was done for gravure printing, there is no reason to think that many of the findings do not apply to flexo for both water-based and solvent-based system. The report is available as a download from the EPA, and it should be required reading for every facility looking to reduce costs and improve print quality. WHERE DOES HEAT COME FROM? Hopefully the savings grabbed your attention. But first, some science, based on our decades in the print room. Before talking about what effects heat has on ink and print- ing, it is worth discussing where the heat comes from to begin with. In applications such as this, heat is typically generated by mechanical friction or by the environment. By looking at each, we can see how to reduce heat in the printing process before talking about controlling it. For the purpose of this discussion, environmental causes of hot ink are passive. One major source, not surprisingly, is the temperature of the pressroom. While some facilities maintain a constant temperature via HVAC systems, many are uncon- Keep Your Cool---And Save Big Dollars Temperature Control is an Essential Part of Process Control By Craig Shields 66F 79F 92F 0 1 2 3 4 5 6 7 8 9 1.6 3.0 4.0 4.5 5.6 7.8 Figure 1 Ink Cons umption (lb/hr) Magenta Cy an • Sources of heat include temperature of the press- room, machine friction, and dryers. • Ink and solvent consumption increase as environ- mental heat increases. • Excessive heat turns flexo dots into donuts. TECHNOLOGIES & TECHNIQUES
Sustainable Fall 2009