The need for laser cleaning of anilox ceramics used in the flexographic printing process occurs after the implementation of the dosing knife and the change of the material on which the surface of these anilox instruments are manufactured.

Why is laser cleaning of anilox ceramics important?

Thanks to the fact that the wear caused by the friction of the rubber rollers, now replaced by the dosing blade, was very low, the anilox was initially made of chrome-plated steel strong enough for this rubber anilox configuration. With the advent of the dosing blade, the anilox now suffers from the wear caused by two steel blades, making it necessary to manufacture them in a much stronger material: ceramic. The new material, unlike chrome, is very porous, which makes cleaning more difficult. In addition, cylinders can now have literature of hundreds of lines per centimeter with very small bushings that soon become dirty and much more difficult to clean. While these high standards have brought flexo to very high levels of print quality, comparable to other printing systems, they have also added several problems related to anilox maintenance. The main problem, apart from the fragility of the cells which are more easily scratched, is the difficulty of cleaning them and the rapidity with which the cells fill with dried ink, which reduces the roller input volume very quickly. This cell opacity problem produces adverse effects, such as less intense prints, difficulty in achieving the desired color and, most importantly, a substantial increase in toning time when starting a new print job, even if it was already a repeat of a job done. Prolonged periods of printer downtime lead to production losses. The most obvious solution is to keep the cylinders clean each time a new job is started.

Maintenance and cleaning of anilox ceramic lasers

To maintain the cylinders with 100% of their available volume, several cleaning techniques can be used, from chemicals to bicarbonate spraying, ultrasound, etc. The most effective and least damaging system for an anilox cylinder is cleaning with a laser beam that removes 100% of the ink residues inside the receptacle. This efficiency is much higher than that achieved by other cleaning systems, and since it is a treatment without chemical or mechanical agents, it does not deteriorate the cylinder cells. Thus, the cylinder can be subjected to a daily cleaning process without affecting its characteristics. The cost of cleaning with this system is also the most economical, since it does not require products and does not generate any waste to be disposed of. Finally, the laser helps us to remove the ink deposited inside the receptacles by heating the ink resin until it becomes a gas. The pigment is suspended in air that is evacuated from inside the machine by an extraction system.

How often should the anilox cylinder be cleaned?

The recommended cleaning frequency of an anilox cylinder is every time it comes out of the machine to be replaced or at most once a week. It is important to keep in mind that the cylinders get dirty every time a job is finished in the cleaning and drying process. It does not get dirty in the printing process, but every time it is cleaned and stopped to wait for the next job. The more changes are made, the more layers will be deposited inside the plinth.

Is laser cleaning safe?

Things to consider when choosing a ceramic anilox laser cleaning anilox
• It should not degrade the ceramic. Chemical products and the action of ultrasound systems can deteriorate them, the mechanical action of particle projection is undoubtedly the least recommended because of its abrasive action and the impossibility of cleaning high line anilox, with very small receptacles, in which solid particles are used in this type of cleaning can not enter. – It must be effective. It is the best option to use cleaning systems that achieve an efficiency of less than 90% and are also not uniform, sometimes 80% is achieved, in others 90%. Therefore, a uniform volume is not achieved and, consequently, there is a reduction of the color toning time since the volume of ink provided by the anilox becomes a variable and not a counter as it would be desirable. – The last aspect to consider is the cleaning speed. The higher the speed, the more cylinders can be cleaned, so cylinder cleaning cycles can be reduced to less than once a week.