Today's Anilox Roll Cleaning – New Laser Technology is a Game Changer
When it comes to new technology, there are certain products that seem to quickly become game changers on how we do things; they just become the norm. So why is this? Usually it is because these products have unique characteristics of ease-of-use, effectiveness, increased productivity, sustainability/environmental impact, and/or safety. New technologies now on the market using a laser to clean anilox rolls contain all of these characteristics, setting them up to be a real game changer.
Previous anilox cleaning technologies ranging from using stainless steel brushes and chemicals, to ultrasonic, to high-pressure solution wash systems, have one thing in common - they each break down ink pigment from the surface of the roll and the cells of the anilox. Regardless which method is used, something is usually left behind in the cells which affects the overall performance and consistency of the roll.
Solvent-based inks are made up of three primary components. The solvent acts like carrier to get the pigment from the bucket to the substrate, the pigment gives the ink color, and the resin offers performance characteristics such as waxes, the ability to stand up to light and not fade, and scuff resistant properties. Water-based inks are formulated using four primary components. Water acts as the carrier, pigment is the colorant, the amines make the resin soluble, and resins offer the same performance characteristics. Which takes us back to the question we asked before; each of these methods break down the ink pigment from the surface in the cells of the roll but aren't the resins leaving things behind in the anilox cells? The answer is “yes”. That's why even after an anilox roll is clean, you often notice the finish is different. For example, the roll may have gone from a matte finish to more of a glossy finish because the remaining waxes within the resin are left behind.
How Laser Cleaning Works
The ability to use lasers to clean anilox rolls has been in existence since 2002. This is not a new idea, but the advancements of laser technologies have allowed these lasers to be more applicable to our industry and be more cost effective.
Laser cleaning ultimately works through laser ablation. In laser ablation, a small volume of material at the surface of the anilox can be evaporated if it’s heated in a very short time. The laser heats the material which absorbs the laser energy and evaporates or sublimates the ink chemistry. There are some particles or residues that cannot be destroyed by the laser but are removed from the surface. This is what the extraction system collects and has the appearance of a fume. The beam intensity is an important factor when destroying the ink chemistry without causing too much heat to damage an anilox roll. The right beam frequency emits enough heat to ablate the ink chemistry without damaging the anilox roll.
The Laserlox™ System uses a 20 watt laser which creates a beam with just enough heat to affect the ink but not the anilox roll. This is the lowest wattage laser on the market, yet still powerful enough to be successful in deep cleaning your anilox inventory.
In addition to the power of the laser, the beam area and the pulse repetition rate (PRR) are essential to its success in anilox cleaning. The beam size influences the cleaning efficiency and cleaning time. The PRR is the frequency of pulses or number of pulses per second. If dwell time is too short, the dust from the ink and the laser pulse interfere with each other. If the PRR is too long, the cleaning will take more time. The appropriate rate allows for the right amount of heat to reach the contaminant, without the dust interfering with the beam. There are no hot spots in the beam, which can be common with other technologies. When scanners pause to change directions, hot spots can occur which can damage an anilox roll.
Not all Laser Anilox Roll Cleaning Systems are created equal. There are various laser technologies on the market. Some may have too high of wattage, or the incorrect marriage of software and motion controls can damage an anilox roll. The laser, software package and motion controls directly affect the cleaning consistency, the effectiveness of the clean and the speed at which the laser cleans. The laser must move smoothly and consistently. Any vibration can create an inconsistent beam and take the laser out of focus.
Why a Game Changer
By using a 20-watt laser, the beam is strong enough to ablate any ink, varnish, or coating chemistry without touching the ceramic or chrome coating on your anilox rolls, deep cleaning them to a level only seen when they were brand new. Using thousands of micro beams or pulses per second allows all components of the ink or coating to be vaporized as the light reaches all the way down inside each cell of even the highest line count roll.
This new technology is basically plug-and-play and automated, giving it a high level of ease-of-use. The laser automatically focuses, allowing anilox rolls of various diameters and widths to be cleaned in the same pass without any operator intervention whatsoever. If desired, the roll parameters can then be saved for easy recall, which minimizes any set up time in the future. There are no air lines, no water lines, no external exhaust is required. The devices utilize standard power 100/220 V single phase, and the units can be installed within an hour. An operator can literally be trained in only 1 to 2 hours.
The sustainability or impact on environment that these lasers have is impressive as well. This anilox cleaning technology does not require any chemicals, media i.e. sodium bicarbonate or polymer beads, water, detergents, or waste disposal of any kind. Equally as impressive, the systems use only 4 kW of power per hour. This low energy consumption is actually less than a standard household dishwasher.
Last, but certainly not least, are the safety features of laser cleaning anilox technology. Eliminating caustic chemicals and waste is definitely at the forefront. Every year individuals suffer from eye injuries and skin irritations/burns from caustic chemicals used in the printing industry. Minimizing the use of these chemicals is certainly a step in the right direction. Lasers used in these cleaning systems are considered to be Class 4, however they are completely contained with interlocks which result in the unit being rated as a Class 1 device by the FDA. The definition of Class 1 is equipment inherently safe with no possible ability of eye damage.
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