How much ceramic-coating porosity is acceptable in anilox-roll manufacturing?
In what may be the most important component in flexographic printing, an anilox roll’s manufacture starts with the steel base core. The core—whether machined from a solid piece of steel or from a steel tube with fitted plugs that form the journals—is the foundation of the roll. Bearings fitted onto the journals allow the roll to rotate in place in the press. To insure a snug fit for the bearings, the journals are precision-machined to exacting tolerances for diameter and concentricity with the face. The face of the core is machined to a predetermined dimension under the finished diameter tolerance. Undercutting the face provides room for the ceramic coating. The surface is then grit-blasted to rough it up so the ceramic can grip to it. The ceramic used for anilox rolls is chrome oxide (Cr203)—essentially crushed rock. The microscopic particles of chrome-oxide powder are fed into an intense flame (plasma) formed as a gas is fed into a high-voltage electrical arc between an anode and cat
