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FLEXO Magazine : August 2013
MYTHS DISPELLED Since UV LED is not, by itself, a particularly new technology, many printers and converters have heard about it. They have also heard about various “problems” and “issues” that such systems face. We would be remiss, then, if we did not dispel some of the myths by highlighting just how far UV LED technology has come. Myth #1: “LED lights are not powerful enough to get a good/ fast cure.” Older UV LED systems had an irradiance of 8 W/cm2 or less. Newer systems, like Mark Andy ProLED, have an output of 16 W/ cm2— more than enough for a good, fast cure. Myth #2: UV LED requires special inks, and the inks needed just are not available. UV LED does require specially formulated inks. However, there is a wide variety of inks and coatings now available for use with UV LED, comparable with those available for tradi- tional UV curing. Myth #3: UV curing can tend to “yellow” inks. True, older photo-initiators would tend to turn yellow if over-ex- posed. This was especially noticeable with lighter inks. But newer formulations use photo-initiators that minimize or else eliminate this problem. Myth #4: UV LED is unproven technology. This is no longer true. Mark Andy ran a successful demon- stration of UV LED at Labelexpo 2012, showing that the system could successfully cure a full range of inks at typical press speeds. There has also been extensive testing at a beta site us- ing dozens of materials and various press speeds. The finding has been that UV LED produces a consistent, quality cure at typical press speeds to equal or even better performance over traditional UV technology. on adoption of a new system. In other words, new technology must address: 1. Productivity issues: New technology should improve productivity and, hence, have a bottom-line impact 2. “Green” issues: New technology should minimize safety concerns and environmental impact 3. Capabilities expansion: New technologies should make new processes possible, or else eliminate barriers to adopting existing technologies. In other words, new technology should have a capabilities impact The important thing to remember is that the impact of a new technology rarely comes from a single, large-scale innovation. “Game changers” are rare in any industry. But, a piece of technology can have a large overall impact by improving many small aspects of a process simultaneously. In short, a series of small-but-significant benefits is often the most realistic option, and it is most likely to make a positive return on investment. With this idea in mind, let’s take look at the impact of UV LED on the printing process. SPEED & SAVINGS Press uptime and press speed are two critical factors in controlling costs and keeping production working as efficiently as possible. How does UV LED compare with traditional mercury bulbs where uptime and speed are concerned? Here, there is no contest: 68 FLEXO august 2013 www.flexography.org Figure 2: Wavelength comparison of uV LED and traditional mercury (Hg) lamp.