How to Prevent Anilox Roll Scoring

Anilox roll scoring poses a challenge for many printers, evident when a shiny line encircles the roll, indicating a groove or “scoring” of the anilox roll. If you are a printer this means dark lines in your print – especially when printing solids. If you are applying a coating, it’s even more important to reduce scoring since most coatings are clear, and heavy coating lines are hard to detect.

Once scored, an anilox roll can often be used selectively, working around the score lines. But at some point, the roll needs to be reengraved and depending on size and finish, comes with a significant cost.

Scoring often arises from debris trapped between the doctor blade and the anilox roll. Common sources include particles from steel doctor blades, dried ink build-up, or coating particles in the fluid delivery system. To minimize or eliminate anilox scoring, consider the following practices:

1. Maintain Good Housekeeping:  

• Prevent dried ink or coating from accumulating on the anilox rolls and related components within the ink delivery system
• Use filtration in the fluid delivery system to remove dried, hard debris during prolonged production runs.

2. Implement Magnets: 

• If using metal doctor blades, add high-strength magnets to the fluid delivery system to capture steel particulates.
• Maintain minimal pressure between the doctor blade & anilox roll when using steel blades to avoid entrapment of dried particulates.

3. Optimize Mechanical Setup:  

• Ensure level and parallel alignment of the doctor blade chamber or single blade holder with the anilox roll.
• Misalignment can lead to excessive pressure needed to engage the doctor blade, this will bend the blade and increase chances for particle entrapment.

4. Use Plastic Containment Blades:  

• Consider using a plastic (polyester) doctor blade for the containment blade on enclosed chambers.
• This change cuts steel doctor blade usage (and particulate) in half, reducing the chances for scoring to occur.

5. Switch to Polymer Doctor Blades: 

• Explore transitioning to plastic or polymer doctor blades to eliminate steel from your system.
• Polymer doctor blades have advanced dramatically in terms of stiffness, edge smoothness, blade life, and durability for long production runs and offer metering quality that meets or exceeds steel.

In conclusion, anilox scoring is permanent damage commonly caused by debris between the doctor blade and the anilox roll, resulting in a defective product. Minimize anilox scoring and save unnecessary engraving costs by filtering inks or coatings and using magnets with metal doctor blades. Alternatively, you can switch to plastic doctor blades to potentially eliminate the problem altogether.