Four operation skills of the hottest plane color s

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Four operation skills of flat color silk printing process

1. Selection of plate making film

in order to obtain screen printing brushes with rich layers, first make film like offset plate making, and select point output of 100 ~ 133 lines/inch. Too high line number is not conducive to the recurrence of medium and low-key levels. If Zhiren company takes the lead in launching the circular dots for non oxidized color mirror aluminum plate in China, because the reproduction curve of silk printing dots is reduced below 20% and increased at 70% of the dots, the image should be adjusted for the gradient curve before the film is released. Generally, the adding angle of the film is: magenta version 15 °, green version 75 °, yellow version 90 °, black version 45 °. Practice has proved that overprint moire rarely occurs. In addition, in order to ensure the accuracy of overprint in the later stage, sulfuric acid paper negatives should not be used as far as possible, even for line printing. If you don't have a prepress production department, don't entrust an advertising banner production company to produce print film, because the number of film lines they produce is low and the level is lost, which will affect the printing clarity

the international influence of the plastic extruder industry continues to rise. 2. The choice of silk

high mesh yellow plain woven polyester silk is a necessary condition for high-precision printing plates. Yellow is to reduce the diffuse reflection of exposure light when printing; Flat weave can form a thinner version, which is convenient for high-profile and low-key reproduction. The same mesh of silk has a variety of wire diameters to choose from, which should not be easy to break. The ratio of wire mesh to film threading is 3.5:1. If the threading number is 120 Wires/inch, 420 wires should be selected

3. Stretching

using a large format mechanical stretching machine can obtain a large tension to prevent tension relaxation and plate deformation during the printing process; The tension of the same set should be consistent; It is inclined and stretched, and the longitude and latitude lines of the cloth are at an angle of 22.5 ° with the frame, which is conducive to reducing the point deformity and making the small text and lines perfect. When stretching, the initial tension should be large, and then pull it every 1 hour. After 12 hours, measure the tension of the plate with a tensiometer. The tension difference of each part is required to be no more than 1n/cm (the tension after pasting and printing is 24 ~ 25N/cm). In addition, aluminum alloy or steel frame should be selected, and the wooden frame is easy to deform after soaking in water

4. Edition making

take the direct legal edition as an example. After pretreatment, the silk is coated twice on the ink scraping surface and once on the printing surface with the printing surface facing down (it should be in a dust-free environment); Then, complete the drying at a suitable temperature (generally 35 ~ 45 ℃), and the measured tension is not less than 18 n/cm; The thickness of photosensitive adhesive layer shall be controlled within 10 ~ 18 μ m. The thickness of the emulsion layer on the printing surface is about 10% of the thickness of the silk, and the RZ value (layout roughness) is less than the thickness of the emulsion layer. In the coating process, it is very necessary to control the thickness of the version. When it is too thick, the dark tone level cannot be separated, and the highlight cannot be printed; Rough and uneven version will cause abnormal increase and tone change. These data can be controlled through instrument measurement

The production quality of the

version is the basis for accurate overprint, stable dot reproduction and good gradation reproduction. If the customer provides offset image files, offset proofing or color spray proofs, the reproduction of color printing will depend on the operator's understanding of silk printing. Before printing, check the adhesion between the emulsion surface of the positive film and the printing surface of the plate, and make the film and the plate free of Moire through the rotation angle, and then fix it with adhesive tape

excellent equipment - printing

excellent equipment can ensure that we can obtain good printing quality. In order to ensure the accuracy of overprinting, which has caused great pressure on the local ecosystem, we should choose high-precision printing machine. The plate frame lifting printing machine is better, and the printing format should not be too large. Considering comprehensively, A3 format is appropriate. The printing material can be transfer paper or low flexibility transfer film, which is pre shrunk by hot air before printing. The printing materials that have not been printed in a day shall be wrapped with plastic film to prevent moisture. The hardness of the squeegee is hs80 ~ 90. On the premise of not affecting the tone, try to use a hard squeegee to form a thinner ink layer, which is conducive to the reproduction of the tone level

the color sequence of machine printing is magenta, cyan, yellow and black. The reason why magenta is placed in the first color sequence is that the magenta version has a large layout, which is convenient for the later colors to overprint; The black version has a short tone and is suitable for putting at the end. Magenta, sky blue, medium yellow and black four-color inks are generally used as printing inks. Like offset paper inks, if there is a large color deviation, scarlet, common blue, lemon yellow or transparent yellow can be used instead

distance is an important factor affecting the printing process and quality. The distance of plane color printing is mostly 5mm. Too large distance is bad for overprint and easy to break; If the distance is too small, it is easy to stick. The printing pressure is divided into the horizontal shear force on the ink and the vertical downward pressure. The latter is the premise to ensure the contact between the plate and the substrate. The digital display electronic tensile testing machine with good ink can detect and transfer the stretching, tearing, peeling, tightening, bending, shearing, bursting, puncturing, fatigue and other items of metal materials and non-metal and high molecular materials. The control of actual printing pressure is based on the principle of ensuring that the tone is basically complete and the color of key positions is truthfully restored

at present, China's flat color printing is still in the exploratory stage, and there is no corresponding standardized data management system in the management of color reproduction

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