Using Rags & Brushes on an Anilox Roll
There are many different products that can be used to clean an anilox roll. The most common is a shop rag. But shop rags can contain metal fragments they picked up in a previous life at a manufacturing facility or machine shop. They are then spun clean and sent to their next location. Because of this, it is highly recommended to use metal free rags. Although they may cost a bit more, it is well worth it.
Another common tool for cleaning is a microfiber sponge. These can work great to mold to the contours of the roll and their flexible nature allows them to really get into the cells.
Under no circumstances is it OK to clean an anilox with abrasive pads. They go by many names:
- SOS pads
- Steel wool
- Green abrasive pads
- White abrasive pads
Any type of abrasive pad will polish down the engraving, reducing the roll’s volume and life.
On the flip side, it is OK to use an approved stainless steel cleaning brush. This is not an invitation to go to Home Depot or Lowe’s and purchase a barbecue cleaning brush; that’s not the proper type of metal and it will damage your anilox roll. Stainless steel anilox roll cleaning brushes have a metal that is softer than the ceramic and therefore will not damage the roll. It is important to note there are also brass brushes that are not to be used with ceramic rolls—they are made for chrome aniloxes. The stainless steel brushes should not be used on chrome rolls either, as it will scratch them.
The bristles on an anilox roll brush are larger than the opening of most cells and therefore will not fit inside them. The cleaning magic happens when you use the brush and an appropriate cleaner in a circular motion. This action pushes the cleaner into the cells and helps pull the ink out.
I am always asked, “How long do I need to scrub the anilox roll?” My answer is simple: Until the roll is clean. There is no magic number of circles or a set time. Prove the roll is clean by looking at the cells with a microscope and then you can stop cleaning.
Using Liquid Cleaners on an Anilox Roll
Every plant is using a different cleaner and there are thousands of options out there. Some are effective and some will damage your rolls. I recommend referring to your anilox roll experts on what to use.
Be cautious when using corrosive cleaners. The pH range for cleaners used on an anilox roll should be between 5.5 and 11.5. Any cleaner outside this range is likely to damage the roll. I will note that some cleaning systems use corrosive cleaners to aid in the cleaning. This type of system minimizes the time the cleaner is in contact with the roll, as they are then rinsed thoroughly.
Prove the roll is clean by looking at the cells with a microscope and then you can stop cleaning
With a lengthy exposure time, chemicals can migrate through the roll to the base material. As we discussed, damage and cracks make this migration even easier. If the chemicals are outside of the acceptable pH range, they can cause the ceramic to blister; delamination of the ceramic could also occur. This will not happen overnight and can be prevented by using the proper cleaners.
Most anilox roll bases are made from mild steel, but many sleeves and some lightweight rolls are made with aluminum. Some cleaners will attack and corrode aluminum, and should obviously be avoided if you have rolls made from that material.
Anilox Roll Storage & Shielding
Protect your anilox roll investment by storing them properly. Keep in mind that dragging a roll on anything increases the likelihood of scratches to its face. Dried ink is extremely hard and will damage a roll. If it is on covers or storage shelves, it will increase the likelihood of damage. Consider ergonomics to aid in a storage system’s ease of use. Design an area that is easy to access and has sufficient room to remove the rolls without them contacting or bumping into each other.
Shield your anilox rolls by covering them. Covers work great, but only when they are actually covering the roll. Having them sit in a drawer or on the floor will do you no good. The cleanliness of a roll cover is also important, particularly with UV inks, where the ink can spread when not cured.