Sleeve processing accuracy
During the processing of the sleeve, the most important and critical link should be accurate post-processing processing to ensure that each index is controlled within the specified error range. In particular, the anilox roller sleeve must be constantly in contact with the squeegee, and it must be ensured to operate coaxially. For the anilox roller, even if it is only slightly uneven or pit, it will produce a long service life for the squeegee and the sleeve. Bad effects. In general, the higher the screen number of the anilox roller is, the thinner the net wall is, and the more sensitive the force acting on the mechanism is, the more obvious the accuracy effect will be. In addition, errors in cylindricity, concentricity, and perimeter are also important for the sleeve. Therefore, it is necessary to make the sleeve as accurate as possible.
It is worth noting that since the sleeve may have some deformation after it is detached, when measuring the error of the sleeve, the sleeve should be mounted on the air-bearing roll, preferably left for 5 minutes to ensure all The compressed air is discharged, and the sleeve and the air-bearing roller gradually adapt to the air-suppressing roller and reach a stable state before measuring, so that truly accurate measurement data of the sleeve error can be obtained.
1. Diameter size and error
The sleeve must have a precise diameter, which is the most basic requirement. In general, the diameter tolerance of the sleeve is ±0.001 inches. In addition, in order to enable the sleeve to be tightly held together with the air support roller of the printing press during expansion and contraction, the inner diameter of the sleeve must be slightly smaller than the outer diameter of the press air bearing roll. The error is generally controlled within 0.0015 inches, that is, the inner diameter of the sleeve is 0.0015 inches smaller than the outer diameter of the air-blanket roller of the printing press, so as to ensure that the sleeve is tightly and tightly set on the air-bearing roller of the printing press .
2. Concentricity
Concentricity is a very important space tolerance indicator for all anilox rollers. It represents the amount of deviation between the sleeve and the absolute center axis in the case of rotation. This is an indicator of dynamic balance on one side of the sleeve. If the jitter error cannot be eliminated, there is an inconsistency in the circumferential direction of the sleeve. Once the allowable tolerance range is exceeded, streaks, ie, ink bars, are likely to be produced on the print during the printing process. The concentricity error of the sleeve is generally controlled within 0.001 inches.
3. Cylindricity
Cylindrical degree is also very important for the sleeve, and the cylindricity tolerance of the anilox roller sleeve is generally controlled within 0.0005 inches.
It must be pointed out that the above data must be measured at both ends and in the middle of the sleeve.
Sleeve installation and unloading
The sleeve is generally installed on the air-bearing roller. The air-bearing roller is the matching device for the sleeve application. Its appearance is similar to the plate roller. An air intake hole is provided at one end of the air support roller, and compressed air can be filled into the air chamber of the air support roller from this air intake hole. In addition, some small vent holes are also distributed on the surface of the air support roller. The vent hole and the air intake hole are penetrated, and the compressed air charged through the air intake hole can be evenly released from the small vent holes. In other words, when the compressed air is filled from the air inlet hole of the air brace roll, the compressed air will be evenly discharged from the air vent hole of the air brace roll, forming an air cushion layer on the surface of the air brace roll, making the sleeve The inner diameter expands to expand and floats on the air cushion layer, so that the sleeve can be arbitrarily slided back and forth on the air spring roll, so that the sleeve can be installed, unloaded or replaced, even on a wide flexographic printing press It is very easy to change the sleeve.
After the sleeve is installed, the air pump is turned off or the compressed air is shut off. The air between the air brace roll and the sleeve is released, and the sleeve is shrunk and covers the surface of the air bearing roll, and finally the air supporting roll. Closely and seamlessly integrate into one.
Use caution
1. Be sure to keep the surface of the sleeve clean and free of dust, solvents or dry ink blocks. These impurities may gradually penetrate the inside of the sleeve, causing corrosion or destruction of the compressible layer in the middle, resulting in its resilience and Decreased compressibility and ultimately adversely affect print quality.
2. Be sure to use a suitable method to clean the sleeve so as not to damage the sleeve material. For example, the anilox roller sleeve cannot be cleaned by ultrasonic or chemical cleaning methods, nor can it be cleaned with sodium hydroxide solution, otherwise the elastic compressible material of the sleeve will be deformed, and its original shape cannot be restored and maintained. . In addition, since the surface layer of the anilox roller sleeve is made of metal aluminum as the coating layer, some cleaning fluids may damage the aluminum. Therefore, these problems must be taken into account when selecting the cleaning method and the cleaning solvent.
3. The compression layer material of the sleeve must be protected, and it must not be allowed to touch or be contaminated with organic solvents, cutting fluids, grinding fluids, polishing fluids, etc. to prevent its deformation and ensure that the state of the sleeve is always maintained.
4. When installing the sleeve or removing the sleeve from the air-bearing roller, sometimes the operator may twist or rotate the sleeve slightly. It should be noted that the movement should not be too big or too violent, otherwise the sleeve will be deflected, or even Damage the sleeve.
5. In order to prevent the sleeve from being deformed or damaged, it is best to store the sleeve on a special bracket. Do not leave the sleeve in place! In particular, the anilox roller sleeve should pay more attention to this point, otherwise it is very easy to cause the two ends of the ceramic to crack, a small piece of crack will form a small crack, when the sleeve is installed on the bearing of the printing machine, the small crack It will get bigger and bigger, and eventually it will cause the net sleeve to be scrapped.
Conclusion
All in all, the production and development of sleeve technology has provided the vast majority of flexographic printers with great advantages and conveniences, and has adapted to and promoted the development of modern flexographic printing technologies. At present, many flexographic printing companies have adopted the sleeve technology. It can be said that the application sleeve technology has become the trend of the development of flexographic printing. It is believed that in the near future, sleeve technology will achieve greater development. Let us Wait and see.
Source: Xinhua Printing Network