1. Micro-cracks Are Intentional

Gravure chrome should have a micro-cracked surface for doctor blade lubrication. Ideally for solvent-based inks it should have between 200-300 micro-cracks per centimeter. For water-based inks, a finer crack pattern, around 790 micro-cracks per centimeter, helps prevent corrosion of the copper. The crack pattern is influenced by electroplating additives.

2. Copper and Chrome Polish Work Together

The roughness of the copper influences the roughness of the chrome, which follows the surface of the copper like a glove over a hand. That means that to get the perfect cylinder roughness, you must fine-tune the polishing of both the copper and the chrome.

3. Crosshatch Polish Removes Debris

If the roughness of the polish has an X-shaped pattern or is diagonal to the circumference, then it helps move impurities in the ink to the edge of the cylinder where it can fall away and get filtered out by the ink system. Otherwise, debris could get caught under the doctor blade and just keep wearing away at the same spot on the cylinder face.

Conclusion:

A cylinder that is too smooth can lead to insufficient doctor blade lubrication and chrome wear, especially with solvent inks. On the other hand, if it's too rough, enough ink can stay on the cylinder to actually transfer ink to the substrate in non-printing areas, so we should choose appropriate roughness for cylinders.