Application of the hottest sleeve in flexographic

2022-09-23
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Sleeves in flexography which way to go 4、 Structure of sleeve how is the sleeve made? What raw materials are used for processing and manufacturing? The base is composed of glass fiber; A compressible layer composed of special polyurethane rubber (a mixture of glass particles, glass fibers and resins); The surface layer is mainly composed of hard polymers coated with rubber or synthetic materials, and the surface layer of the corrugated roller sleeve is mainly composed of metal aluminum or metal nickel. The sleeve is made of winding technology, and each layer is wound on the surface of the mandrel and bonded together with resin. The hard surface is also composed of bonding materials, which are ground and polished to ensure that they are controlled within the specified error range. In the processing of the sleeve (especially the corrugated roller sleeve), the most important step is accurate post-processing. The corrugated roller sleeve must have an accurate diameter and ensure coaxial operation, because the corrugated roller must constantly contact the doctor blade. Therefore, even if it is slightly uneven or concave, it will affect the service life of the doctor blade and sleeve. Moreover, generally speaking, with the increase of the number of extra lines, this point becomes more obvious. Why do you say so? The reason is that the higher the number of lines added to the wrinkle roll, the thinner the wall thickness and the more sensitive it is to the mechanical force. However, the coaxiality, cylindricity and perimeter errors are also very important to the plate sleeve. Due to the thickness error of printing plate and plate pasting material, the printing quality will become worse, but some compensation can be made. If there is an error in the embossing roller, it is impossible to print normally. Therefore, it is necessary to process the sleeve as accurately as possible. The allowable error range of rotec plate sleeve is as follows: 1. External diameter error: +/- 0.020 mm; 2. Standard total runout error: the maximum is 0.025mm; 3. Cylindricity: max. 0.025 mm. These error measurements should be carried out at both ends and the middle of the sleeve. This should be remembered: the outer diameter of all printing plate sleeves produced by rotec is 0.08 mm larger than the required value. Since the total error is the sum of the two errors of the sleeve support shaft, the error range of the support shaft is as follows: 1. Diameter: +/- 0.015 mm; The workshop of Jinan xinshijin Testing Instrument Co., Ltd., a manufacturer of casting tensile testing machine, is relatively large. 2. Standard total runout error: the maximum is 0.010 mm; 3. Cylindricity: max. 0.005 mm. 5、 Error of sleeve and supporting shaft after the sleeve (without printing plate) is installed, the total error of total runout tolerance and outer diameter can reach +/- 25 microns at most. All other errors are caused by printing plate and plate materials, and the general rule is as follows: the error range of thick materials is slightly larger than that of thin materials. Since all errors are balanced through the adjustment of printing pressure, it is not difficult to see that the use of elastic compressible sleeve still has certain advantages. On the one hand, the surface is precisely ground, because they can see the advertisements of these imported instrument manufacturers in all channels; On the other hand, thin plate materials (0.1mm) are used in combination with thin plates (1.14mm). For the purpose of error itself, it doesn't matter whether the wall thickness of the sleeve is 1.5mm or 70mm. However, if one sleeve is to be installed on another sleeve, the wall thickness is very important. In this case, plus the error of the outer diameter, for some types of sleeves, the error may reach 0.2 mm. 6、 There are two types of hard surface sleeve printing plate sleeve: 1. Sleeve with hard surface, such as rotec blue light sleeve; 2. Sleeve with soft elastic surface. The surface of the blue light sleeve is a hard polymer that has been accurately processed, and it is very hard, so it needs to use foam masking tape. But this kind of glue also has a disadvantage, that is, it will cause error fluctuations, so it is not suitable for high-quality printing. The hard sleeve is mainly printed by thick plate (1.7mm ~ 7mm), and the suitable substrate materials include kraft paper, paperboard, laminated plastic board, paper bags and beverage boxes. The printing result of the hard sleeve is the same as that of the plate cylinder. In practice, the maximum wall thickness of the blue light sleeve is 25 mm. 7、 Soft elastic surface sleeve soft elastic surface sleeve is specially designed and produced for CTP technology and high-quality thin plate flexo printing (thickness of 0.54mm, 0.76mm, 1.14mm and 1.7mm). The surface layer of this sleeve is soft and has very high compression performance. The hardness is 45, 55 and 65 shore A. you can choose the appropriate hardness according to the type of plate and the specific situation of substrate material. The soft elastic surface layer has good toughness, high machining accuracy, and can absorb vibration. In this way, the highlight and field parts can be printed on the same plate at the same time without point deformation. The structure of the soft elastic sleeve is exactly the same as that of the hard roller. They need high viscosity and thin plate adhesive tape (0.1mm). The soft compressible surface layer has high resilience, so even if the diameter of the sleeve is very small, it can ensure that the surface material returns to its original shape within one revolution of the drum. When the printing speed is fast, this is very important if a high field density is required. The soft elastic sleeve seems to set a standard for obtaining high-quality flexographic prints with CTP plates in the future. Fine highlights can be printed with thin plates, and the tensile deformation is smaller. Under good printing conditions, the best quality can be obtained with these sleeves. For rotec sleeves with a wall thickness of 25 mm to 70 mm, such as Mega light, in order to avoid vibration, a special lightweight polyurethane is used to reduce the total weight of the printing plate as much as possible. Like the blue light sleeve, the surface material of mega light sleeve is also hard and soft elastic. These sleeves are specially designed for ci (center imprint) printing machines, so that CI can print images of different lengths with a support shaft. Under the action of pressure, the details of the image (highlights or/and fine lines) are "pressed" into the elastic compressible layer, while the real area will not enter the compressible layer due to its large area, so the pressure will be greater. 8、 Adaptor sleeve adaptor sleeves, such as AIRO light sleeves, are also members of the hard sleeve family. The original intention of the design is to serve as an intermediate between the support shaft and the plate sleeve. The sleeve also has a compressible layer and is equipped with an air passage like the support shaft, with a minimum wall thickness of 25 mm. If the supporting shaft on the printing machine is fixedly assembled, an adapter sleeve can be used. This sleeve is designed for this kind of machine and allows super long printing repetition length. The use of rubber sleeve has opened up a new world for the application of adapter sleeve system. Due to technical reasons, the wall thickness of rubber sleeve is limited to 25 mm. In order to print a long repeated image length with a thin rubber layer, the adapter sleeve is indispensable. The rotec adapter sleeve has an inflation valve, which allows installation off the aircraft. As long as the printer is connected with two air pumps, it is not necessary to remove the adapter sleeve from the support shaft when replacing the sleeve. One air pump inflates the support shaft and the other air pump inflates the adapter sleeve. (to be continued)

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