Anilox Roll Cleaning
It is a fact that every printer asks themselves the same daily question about anilox cleaning. How do I best clean my anilox? What anilox cleaning processes work the best? Are these the best available anilox cleaners?
The Daily Challenge for Printers
I have spent decades in the flexo industry. Much of this time was spent manufacturing all types of anilox rolls and sleeves. The challenge with anilox is maintaining consistent performance of the anilox during every print run. This is a daily challenge for printers globally.
The reality is many printers do not attempt regular anilox cleaning even though it is the heart of the press. Failure to do so will lead to insufficient or inconsistent ink or coating being transferred to the printing plate which will result in poor graphics, insufficient density, poor color quality.
This, in turn, will lead to slower press speeds, more downtime, more make ready, more scrap and more cost.
Another reality is that printers try to clean their anilox with off the shelf store cleaners that are not formulated to remove the inks and coatings and can often lead to the wrong impression that their anilox rolls are clean simply because they have applied a cleaning product to it.
Fortunately, my career has taken me around the world. This has given me the good fortune to test hundreds of anilox cleaning solutions. This has also included testing many models of cleaning equipment in every flexo market segment. Because of this invaluable experience, I know what works best.
The challenge is that multiple ink and coating chemistries are often used on the same press
The challenge is that multiple ink and coating chemistries are often used on the same press and even the same job. This can include water, UV and solvent-based inks and coatings. Even if they are supplied by the same manufacturers often they do not react well together. As a result of this sometimes a cross-linked chemical mixture is created that often will resist most anilox cleaners. This is why it is important to match the anilox cleaning solution to the application.
Another problem for most printers that is often not realized is that many ceramic coatings can be very porous. This problem in addition to the laser engraved surface means that all types of inks and coatings tend to more aggressively attach themselves to the coating which leads to additional cleaning difficulties. Porosity in the ceramic coating will also lead to premature cell wall breakdown which is another cause for inconsistent ink transfer.
Sandon Global Anilox
For the above reasons, we offer the Sandon Global anilox roll which has virtually no porosity due to the densification sealant process and method of plasma coating which makes the coating release better and as a result easier to clean as well as resist plugging for the same reason.
Daily Cleaning of Anilox
Having said that you should clean your anilox on a daily basis it would be appropriate at this point to be more specific about the products we recommend.
For everyday use and general cleaning of your anilox, plates and machine parts we recommend our Realcleen and Plateclean ready to use products where water and UV inks are concerned. When solvent-based inks are used we generally recommend our Smartflex High Tech (ready to use). These products come in 32 oz spray bottles and are great for cleaning up on and around the press room.
For heavier dried ink build ups on your anilox rolls, we strongly recommend our Rejuvenator gel or our star performer called Eliminator that is exceptionally effective for removing staining, camouflaging and banding.
For wide web printers where ink chambers are common we also offer our Realcleen, Deepcleen and Smartflex concentrated solutions that can be diluted with water and pumped through your ink bucket to your ink chamber and pipes for a more thorough cleaning. At the same time, this will help flush out ink from the engraved surface of your anilox and help reduce contamination of your inks when changing from a dark to a lighter color.
These cleaners have been developed over many years from my many years in the flexographic industry. They are proving every day that they are very effective anilox cleaners that can be used for many cleaning applications on and around the press.
With solvent inks, many printers are naturally tempted to use readily available solvents that are used to dilute the inks. While these solutions may be cheap they create a lot of volatile organic compounds in the press room and are less effective when it comes to removing staining and other markings from the anilox surface. Our anilox cleaners have very low or no organic compounds in them and are therefore considered safer for the environment and the operator.
Why we recommend Erazor sponges
A sponge is a sponge, right! Not if it is one of our Erazor sponges! And surely a rag is all you need to clean with? Cloth rags have been used since printing started and are still prevalent in most print shops. While there are cloth rags that can be rented, cleaned and reused they are a significant cost for most printers so many resort to using the cheapest available rag that can be found. This often results in massive amounts of lint and cloth fibers getting into the inks and onto the printing plates and is often the root cause for many hickies and print defects. In addition, when used on press, rags are also the cause of many nip injuries to the operator’s’ hands which is another reason they should be eliminated from the press room.
For all the reasons above this is why we recommend our Erazor sponges. They are lint-free, hold the cleaning product well and wick up the ink from any surface that you are cleaning. When used on-press they do not get wrapped around the operator’s hands thereby eliminating nip injuries.
We offer our standard Erazor sponge made from Melamine, our Erazor plus that has a melamine and plastic scrubby side to it and our Erazor Sandwich sponge which is a sandwich of two melamine layers separated by a plastic middle.
If you need to take a more aggressive approach to the cleaning of your anilox then we would recommend one of our plastic block stainless steel brushes. The plastic block might seem insignificant but it does not swell, warp or rot like a wooden block handle and is less prone to retaining bacteria so is more hygienic for use around the pressroom.
One thing you should never use on a ceramic anilox is a brass bristled brush! Brass is much to soft of a metal and if used on a ceramic anilox will simply transfer the metal directly into the cells and can be almost impossible to remove. Brass can and should be used on mechanically engraved chrome anilox although nylon is a good alternative.
For printing plates, we would recommend our plastic block horse hair brushes. We suggest you leave all of our brushes in a bucket of cleaning solution after use to prevent the bristles from clumping together which if used like this can certainly damage your printing plate.
Mechanical cleaning of your anilox ( Deep Cleaning)
Of course, there is not always the labor available to clean your anilox and no matter how hard you scrub a roll, manual cleaning can only be so effective.
Again after many years of trial and error, I have been able to prove that the most effective technology for cleaning of any anilox is ultrasonic cleaning.
Pressure washers are very popular, but the truth is they are only capable of superficially cleaning the surface and with finer screen counts pressure washers reach only partially into the engraved cells. This means that the anilox is less than 100% clean and is prone to re-plugging when put back on the press. The remaining ink particulate permits the fresh ink to re-attach itself to the remaining particles resulting in the anilox plugging up almost immediately when it is re-used.
Media cleaners are even worse, not only do they not clean particularly well and they leave a significant amount of residue on the face of the anilox and the cells. If you look around all over the press you will see that media cleaners even contaminate your inks and coatings.
Laser cleaners have recently become popular for cleaning but again it is mostly a surface cleaner and can result in the weakening of the cell walls and can leave witness lines on the anilox that cannot be removed.
Each of these technologies are also easily interfered with by the operator such as rotation speed, air pressure, nozzle distance from the anilox surface, and traverse speed. Modifying any or all of these settings can have quite a disastrous result on the anilox. This sometimes results in anilox destruction.
So why did I choose ultrasonics as my cleaning technology? Unlike the above-mentioned systems, our ultrasonic systems are pre-set, and have very little in the way of settings the can be adjusted by the operator. This ensures that each anilox roll is cleaned consistently as it rotates through the solution.
Generally, the anilox does not need to have the gears and bearings removed for cleaning and once the anilox is loaded in the machine the operator can carry on with another job. The major factor, however, is that ultrasonics cleans at a nano-micron size so that not only can it clean any line count, regardless of how fine it is ,it actually will deep clean the coating itself by reaching into the porosity of the coating. We call it Deep Cleaning and results in the anilox staying much cleaner and cleaner for longer as well as restoring the engraved surface back to like new condition.
And just in case you have heard of or have had a bad experience in the past with ultrasonic cleaning, our frequency sweep technology alternates the frequency of the sonics so that there is no possibility of creating any hot spots. This makes it safe for use on any engraving.
For this reason, we do not need to use overly alkaline solutions in our tanks because we are able to clean the anilox for extended periods as needed depending on the degree of contamination and use mostly water dilutable solutions that are safer for the product, the operator and the environment