Beyond Darth Vader
Beyond Star Wars' use of lasers, package printers are using two main types of lasers to engrave cells into anilox rolls.
by Joy English, Assistant Editor
THROUGOUT OUR LIVES, we are constantly fascinated by things that light up. We capture fireflies and "ooh" and "aww" at Fourth of July fireworks. Laser light shows are a big attraction at amusement parks and even science museums, where rays of light dance to funky background music. But these beams of light energy can be very powerful and very useful tools in various industries. In the package-printing industy, lasers are being used to engrave anilox rolls for improved ink dispersion and printing capabilities.
"A laser (Light Amplification by Stimulated Emission of Radiation) is a device that controls the way that energized atoms release photons," explained Steve Slater, technical manager for Pamarco, Inc. This technology is then tailored to fit the purposes of various industries, and for anilox roll engravers, simply speaking, lasers are used to carve cells into the anilox rolls.
Anilox roll laser engraving was developed in the late '70s with the introduction of the CO2 laser. This new laser offered roll engravers a process other than mechanical engraving of anilox rolls. Slater said, "Early production engravings showed initially that the use of laser-engraved chromium oxide had benefits over conventional mechanically-engraved rolls, such as reduced wear, but it was evident that there were some problems that needed sorting out"—such as inconsistency and lack of control. Improvements were made to the CO2 lasers, resulting in a laser that produced a uniform cell structure with consistency, control, and quality ink dispersion.
Several years later, YAG (Yttrium Aluminum Garnet) lasers entered the package-printing world, made commercially available in 1996, with the capability of achieving higher line counts than the CO2 laser could achieve. Even so, Mike McPherron, operations manager for Praxair Surface Technologies, Inc., said, "There are pluses and minuses to each system."