Cleaning anilox rolls using laser technology
To the Editor:
In your recent feature article on “Anilox Roll Cleaners” [September 2005] you mention a variety of methods but omitted the newest technique, laser cleaning. This technique is covered by a US patent issued in 2002 to Jerome Jenkins, the same person who received the original patent for ceramic-coated laser engraved anilox rolls.
Although other cleaning techniques remove a lot of the chemicals found in modern day inks and adhesives that tend to clog anilox roll cells, not even chemical removal touches the Teflon and polyethylene used for mar and abrasion resistance. These two materials are just too inert chemically and once attached to a roll’s surface form a hydrophobic film that causes ink to bead up much like water does on a newly waxed car. The only way to remove these contaminants fully (along with other organics) is to thermally decompose them, which is what laser cleaning accomplishes. It is the same laser beam that could be used to engrave the roll in the first place, but with different optics and other adjustments only burns organics and not the ceramic. We have had customers send the same roll back over a dozen times for cleaning without any loss in volume.
We have a roll microscope with which we take before- and after-cleaning readings on the engraving. Many times rolls come in for cleaning that look as if they don’t need cleaning yet don’t deliver a uniform coating. The readings show nearly the same volume before and after cleaning, yet the roll prints almost like new after cleaning. The scientific reason for this is that the cleaning has restored the dyne surface level of the roll. Ceramic has one of the highest surface energies around, twice as high as most metals. But this also means that contaminants can lower it a lot more than a metal surface as well. All chemical cleanings leave a film on the roll, as do all grit blasting methods of cleaning. Hence they can’t restore the surface energy of the ceramic. Only the laser cleaning can restore the surface.
Laserlife offers laser cleaning along with before and after readings as a quick turnaround service to customers. We are working on a prototype unit to sell or rent to cus