Flexographic printing,because of the use of solvent-based inks,an anilox roll (with a scraper) can replace all the functions of all the ink rollers of a conventional inking system. So, how to produce an anilox roller? It is a special transfer roller for flexographic printing presses. The surface is made up of numerous recesses of the same size, shape, and depth. These recesses are also called cells (or ink holes). Generally, the cells are not visible by the eyes. It must be seen with a magnifying glass. The cell can store ink. Through the irregular shape, size, and depth of the anilox roller, the amount of ink can be controlled to achieve the desired thickness of the ink layer. The anilox roller plays an important role in flexographic printing.
Anilox roll processing process
The anilox roll can be divided into a metal chrome-plated anilox roll and a ceramic anilox roll according to the surface plating. The metal chrome-plated anilox roll is made by engraving a cell on the surface of the metal roll with an electronic engraving machine and then chrome-plated. The ceramic anilox roll is a plasma method that uses a metal oxide (aluminum oxide or trioxide). Chromium) is melted and sprayed on the surface of the metal roller and bonded to the metal roller to form a high hardness, dense ceramic film, which is then laser engraved.
The processing process of the anilox roller is as follows:
Roller pre-processing—-mesh processing—-post-processing
1. Roller top processing Roller pre-machining refers to the machining process before the anilox roller processing the wire. It mainly includes the processes of pre-plating, electroplating and post-plating. The substrate of the anilox roll is generally made of high-quality carbon. For steel pipes, most of them are medium carbon steel pipes. The wall thickness of steel pipes is 7—10 mm. The roller structure is in the form of a shaft roller. That is, the flange and the mandrel are connected with the steel pipe.
The pre-plating process is as follows:
Roughing—dynamic balancing—-axis and flange processing—welding–machining—tempering treatment—semi-finishing—finishing
Before the plating, the outer circle center of the roller of the anilox roller should coincide with the center of the inner hole of the flange, and the different center of gravity should be no more than 0.002mm. The dimensional accuracy of the outer circle of the roller should not be lower than 2. The surface roughness is on the axis. The neck and wheel parts are generally 0.8. Electroplating refers to the nickel and copper plating on the surface of the roller body to form a textured substrate layer on the surface of the roller body. The post-plating processing is the final step of the roll body pre-processing, that is, in the copper plating. After the netting process, the roller body is subjected to the grinding process. The so-called car grinding process refers to the process of finishing the copper surface of the roller body with a special turning tool or a grinding wheel or a fine sandpaper. The surface of the roller body after the grinding process The following requirements should be met:
The roller body diameter should be equal to the plate cylinder, and its dimensional accuracy is not less than 2:
The ovality of the roller body is ≤0.015mm;
Radial runout ≤0.006mm I
Different axial degrees ≤0.009mm.
2. Texture processing
Reticulation is the formation of the desired texture or ink pocket on the surface of the roll. There are several methods for processing the anilox roll web.
(1) Machining method A method of processing a netting directly on the surface of a roller by a diamond cutter head or a special rolling cutter. This processing method is relatively simple and low in cost. Generally, it is limited to the anilox roller with T 200 line/in (lin=0.0254m).
(2) Photographic Corrosion Method The method of fabricating the corrugated roller for phase and corrosion using the grating mask technology. Due to the high technical level required, its application is limited.
(3) The electronic engraving method utilizes the principle of photoelectric conversion. The processing method of engraving ink holes on the electronic engraving machine. This processing technology has a high quality of texture processing, good quality stability, and can process the anilox roller of high mesh line. It is a typical process for processing high-quality anilox rolls abroad.
(4) Laser engraving ceramic anilox roller The above anilox roller belongs to a metal anilox roller. After chrome plating, although the wear resistance can be improved, the service life of the anilox roll is limited due to the small thickness of the chrome layer. Therefore, the ceramic anilox roll manufacturing technology has been developed. The surface of the substrate is sprayed with a ceramic thickness of about 0.6 mm. After grinding, polishing, and finally, the ink hole is directly engraved on the ceramic surface by a laser beam.
This processing method is more efficient. The ceramic surface has a high hardness. The Vickers hardness can reach 1300, and its wear resistance is more than 5 times that of the chrome-plated roller. It has been applied and popularized.
3. Post processing
After the netting process, in order to improve the wear resistance, it should be chrome-plated. The thickness of the chrome layer is 0.01-0.15mm. Since the chromium is silver-white metal, it has a very high hardness, generally HV800-1000. Therefore, after chrome plating Significantly improve wear resistance.