How to select and extend the service life of anilox rollers? These tips you need to know!

How to select and extend the service life of anilox rollers? These tips you need to know!

The anilox roller, also known as the anilox ink transfer roller, is one of the most important components in flexographic printing equipment, used to precisely control the amount of ink transferred onto the plate and subsequently onto the substrate. However, improper use during printing can easily cause malfunctions, shortening the service life of the anilox roller and affecting the stability of print quality. So, how should anilox rollers be used and maintained correctly? Below, we will provide an in-depth understanding of anilox rollers through three maintenance sections: their structure and types, parameters, and maintenance recommendations.

Structure and types of anilox rollers

From the surface structure of the anilox roller body, it mainly consists of two parts: the mesh cavity and the mesh wall; From the structural composition of anilox rollers, they mainly consist of the roller core, base material, and surface coating. Among these, electroplated copper is commonly used as the base material, which forms the basis for making mesh cavities and mesh walls for patterned rollers; Surface coatings use metallic chromium or ceramics, mainly to improve the wear resistance of the anilox roller and prevent solvent corrosion of the base copper layer.

According to the different surface coatings of anilox rollers, they can be divided into metal chrome-plated and ceramic anilox rollers. In terms of engraving precision, printing resistance, and ink transfer and release performance, ceramic anilox rolls have more advantages, so enterprises tend to use ceramic anilox rolls more frequently.

Parameters of the anilox roller

The function of the anilox roller is to transfer ink quantitatively and evenly to the printed plate with text and images. Whether the anilox roller can transfer ink quantitatively, evenly, and accurately depends on its parameters.

01

Shape of the web hole

The shape of the mesh hole includes quadrilateral pyramid, quadrilateral platform, hexagonal platform, and spiral shape. Currently, most quadrilateral conical mesh holes are found on metal anilox rollers and are completed using electronic engraving technology; Most hexagonal cylindrical mesh holes are found on ceramic anilox rollers and are made by laser engraving. Compared to four-sided pyramidal cavities, hexagonal pyramidal mesh cavities have the characteristics of storing more ink and better ink transfer and release performance.

02

Add the number of network cables

The number of mesh lines is the number of cavities per unit length along the axial direction of the anilox roller, measured in lines per inch (l/inch as lpi) or lines per centimeter (l/cm). The number of screened lines does not directly correspond to the clarity of printed images and text, but it does affect the quality of printed images and text.

03

Arrangement angles

Anilox rollers made by electronic engraving can carve mesh holes of 30°, 45°, and 60° depending on the angle of the engraving blade, while laser engraving usually produces mesh holes with 60° regular six deformities.

04

Mesh opening, depth, and opening

The cavity opening refers to the width of the surface opening of the cavity, usually denoted as b; Nest depth refers to the depth of the cavity, usually denoted by H; The opening degree of the cavity refers to the percentage of the cavity depth (H) to the cavity opening (b), usually between 23%~33%.

05

The net hole holds capacity

Cavity volume refers to the total amount of ink that can be held per unit surface area of an anilox roller, measured in BCM/in² (B-Billion; C-Cubic; M-Micro).

Maintenance recommendations for anilox rollers

Achieving sufficient color density and reproducing the same printing effect in each continuous print is a common goal for flexographic printing companies. By using the same anilox roller daily, color matching time can be significantly shortened. At its core lies in standardized printing processes, and a comprehensive cleaning and maintenance mechanism is an indispensable part of this process. Investing effort in developing maintenance plans tailored to your needs and strictly following them will save you significant time, cost, and effort. The following professional advice on anilox roller maintenance can help you get by.

01

Inspection upon receipt

Check whether the anilox roller packaging box/crate is damaged during transportation. If obvious damage is found, contact the carrier immediately to clarify responsibility.

02

Handle with care

Remove the roller from the packaging and unseal it for inspection; be sure to handle it carefully. Any dents, depressions, or scratches can damage the engraved mesh hole and affect print quality.

03

Proper protection

Always handle the anilox roller by hand or lifting equipment; dragging is strictly prohibited. When idle, cover with a protective cover to prevent accidental damage.

04

Dynamic maintenance

If the machine is temporarily stopped during printing, the ink path must be maintained and the anilox roller rotation to prevent ink from drying and forming a crust inside the cavities.

05

Scraper operation standard

When changing colors, release the contact between the scraper and the roller surface to prevent ink buildup. When using the scraper system, be sure to install filters and magnets to prevent metal particles from scratching the surface of the anilox rollers.

06

Clean daily

Ideally, the roller surface should be cleaned immediately after each batch of printing is finished. Operators need to develop daily cleaning habits. Generally, ceramic rollers use stainless steel brushes, and brass brushes are prohibited; When cleaning, gently brush along the circumference and use a specialized cleaning agent.

07

pH level control

Do not use strong acid or strong alkaline cleaners, as this may cause the ceramic layer to bubble or peel off. The pH value of the cleaner should be controlled within the range of 6.5-11.8.

08

Material compatibility

Aluminum-based roller cores are more susceptible to corrosion and require gentle chemical or mechanical cleaning, avoiding strong solvents.

09

Dedicated maintenance for sleeves

The anilox roller sleeve must use an "aluminum safety" cleaner to keep the inner bore and both ends clean and free of dry ink. Protective end covers must be worn during cleaning to prevent chemical solvents from contacting the internal composite layer (which may cause the ceramic layer to peel off). During chemical immersion cleaning, the temperature must not exceed 120°F (49°C).

10

Finishing touch

After cleaning, rinse thoroughly and ensure the roller surface and both ends are completely dry, then remove residue with alcohol wipes or specialized surface cleaners. When using compressed air for drying, ensure the air source is oil-free.

The above recommendations form the basic framework for building a maintenance system for anilox rollers, aiming to extend the service life and performance stability of anilox rollers, and to reduce costs and increase efficiency through process optimization. At the same time, it is recommended to conduct specialized employee training simultaneously to ensure operators master proper cleaning and operating procedures and to establish dual risk awareness; It is recommended that each printing company establish a dedicated offline maintenance area for anilox rollers, equipped with deep cleaning and testing equipment, and establish a periodic maintenance mechanism.