What's Really Going on with Your Anilox Rolls?
- Published: June 01, 2001, By Bob Temple Absolutely, Micro*Clean Intl.
Most converters have a general idea on the mechanics of how an anilox roll works. But few people actually have the proper equipment to keep tabs on their anilox inventory.
It really does make sense (with all the money invested in an anilox inventory) to have a few basic tools to keep track of these expensive treasures. After all, they truly are the heart and soul of the press.
Using the Right Tool
Do you have problems holding density on press? What about wavy patterns or ghosting? Are your solids really uniform, or are there lines running through them?
In what condition are the aniloxes? Dirty? Clean? Score lines? Broken walls? Worn-down walls? How do you tell?
Most print managers will have a pocket microscope that may be 20x or 40x or even 100x. This will give them a basic look at cell walls from 150-line up to 550-line, but from there the cell structure is just too small.
The best method is to use a quality scope designed to work on anilox rolls. This is an incredibly valuable tool, because it can actually let you look down into an individual cell. You can take an accurate depth measurement by using a digital gauge.
Let's say that you have a 400-line anilox roll and you know that it is engraved to a depth of 21 microns, but with the scope you get a reading of 14 microns. You now know that it is dirty.
You will not be getting the full ink release for which it was designed. So at that point, you know that it's time for a deep cleaning. With the scope, you re-evaluate after cleaning.
Some facilities utilize roll scopes with a video camera that allows you to put it up on a TV screen. With magnification of 200x-600x-800x-1,200x, you can get very “up close and personal.”
On an 800-line anilox roll, you are able to actually look at the bottom of an individual cell and slowly go up to the top for an accurate measurement.
Before and After
Figure 1 shows before and after pictures taken from the roll scope. In the “before” picture, notice the dried ink in the cells. By using the focal point, you easily can get a depth from the ink level to the top of the cell walls.
Some of the walls show a shiny area where the doctor blade has been riding and results in a widening of the land area. Over time, as the walls wear down, your cells will hold less and less volume of ink, and you will lose density on press. With a good scope you easily can see when this happens and be able to tell when to send your roll out to be recoated.
It is important at this point to stress that a good tracking system will save you thousands of dollars in aniloxes and help reduce press downtime.
Also, having one person in charge of overseeing your anilox inventory greatly improves your productivity and bottom line. Recently, I was in a large plant in Brazil that had an employee whose sole job was to keep tabs on the entire inventory of anilox rolls. He had set up a computer tracking program showing the original date of service and all the specifications about each roll. This included line screen, liquid volume, the actual depth in microns, as well as width and cell wall.
Each time a roll comes out of the press, it is inspected by both liquid volume and the microscope; then all the information is recorded. If it is dirty, he puts it through the cleaning process and then records the final specifications. This helps the company tell the overall performance of the individual anilox, as well as the state of the entire inventory.
This is one example of a great way to keep tabs on an important investment!
Bob Temple is owner and president of Temple Assoc., Cesco, and Absolutely Micro*Clean Intl. His company specializes in conformal coatings removal, sputter chambers, and any product that requires a special finish. Absolutely Micro*Clean uses computer-controlled automation in its blasting operation in many aspects of the printing industry, including cleaning anilox rolls, gravure cylinders, doctors blade chambers, and more. Contact Bob at 916/635-4337.
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