The Easiest Way to Longer Anilox Roll Life
The ability to use an anilox roll to its full potential should be a very simple process. You follow the installation instructions, run the press and eventually replace it after wearing down the engravings, right? Unfortunately, in the thousand+ anilox roll audits I perform each year, around ninety-nine percent of the anilox roll sleeves have ink buildup on the ends of the inner diameter (ID). That fact basically guarantees a shorter anilox roll life, but it doesn’t have to be that way. If you’ll give me a few minutes of your time, I’d like to tell you what the problems are, why rolls should last longer and how you can make that happen – with one simple step.
I’ve noticed that I get asked a few questions over and over again in regards to anilox roll sleeves. I think by addressing these problems, we can begin to tackle the heart of getting the fullest potential from your anilox rolls.
These are the top three questions:
1– Why do sleeves always stick to the mandrels? 2– Why are sleeves so hard to install into the press? 3– Why are they so hard to get out of the press?
First we must understand the design of the sleeves. There is a fiberglass tube wrapped in foam, which is located within an aluminum tube that has been coated and engraved. This design parameter allows the ID of the sleeve to slightly expand as we apply air to the press mandrel when sliding the sleeve into position on the press. The goal, once in the press, is for that anilox roll sleeve to grip tight to the press mandrel so it doesn’t slip.
What that means is that the specification tolerances between press mandrel and anilox roll ID are extremely close – and we want them to be! This is where quality print comes from. We want the specifications to be so tight that it’s on the verge of being an interference when the air is taken away from the mandrel – that’s the perfect balance. But this is also where anilox roll lifespans are shortened: if anything causes the press mandrel to grow or the ID of the sleeve to shrink, it will alter those tolerances and harshly affect how the sleeve goes in and out of the machine.
The major problem I see in mandrel growth is buildup of ink, which often leads to anilox sleeves becoming stuck on the mandrel and usually means rough handling to get them off. The most common way I hear of operators getting stuck sleeves off is by hammering them out with a metal hammer, using a piece of wood to soften the blow. This essentially guarantees edge chipping – not a problem anyone wants to deal with.
Once anilox roll and sleeve edges start to chip, those chipped areas continue to grow and lead to ink leakage. That precipitates the buildup of ink on the ID of the sleeve and the outer diameter (OD) of the mandrel. Edge chipping can also introduce contaminants of ceramic particles into the ink. As the chips continue to grow, these particles are introduced into the ink system which then recirculates and often results in particles becoming lodged between the blade and the surface. These wedges become scorelines and we know what that means for our print.
The chain reaction of having these tight tolerance sleeve – mandrel – anilox configurations mixed with buildup or unclean surfaces ultimately leads to reduced anilox roll life and poor sleeve performance. The simple fix I promised? Wipe the mandrel off every time a roller comes out of the machine and quickly wipe the sleeve ID, too. It’s really that easy.
It is far less complicated to keep a new sleeve clean by giving it a quick wipe every time it comes out of the press than trying to clean off months and months of buildup (which is often impossible to do!). Another tip, hopefully just a reminder, is that we never apply lubricants or grease to the press mandrel or ID of the sleeve. This guarantees buildup, reduction of sleeve ID and increase in the OD of the mandrel.
The goal is always getting anilox roll usage to the point that the engravings are wearing down: that’s the full life of an anilox roll. If you follow these simple cleaning suggestions, you’ll soon see that scorelines and plugging problems can be far less common to your shop. If you’re wearing out the engravings on your rolls, you’re maximizing the life of your anilox rolls – and that’s how you get the most out of your investment.
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