Selection of the most popular mesh size and influe

2022-07-30
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The selection of wire mesh number and the influencing factors of printing plate quality (2)

second, the influence of temperature on printing plate quality the quality of printing plate is related to various temperatures during production. The temperature includes: 1. Operating room temperature; 2. Temperature in the oven; 3. Temperature in exposure box; 4. Developer temperature

l. temperature in the operating room

generally, the temperature in the operating room should be kept at about 25 ℃. Pay attention to temperature regulation and control in winter and summer

for version F, the effect of room temperature is not obvious

for version D, in hot weather, if the room temperature is not well controlled, the following problems will occur:

① the prepared glue is very easy to produce thermal crosslinking, which makes it difficult or impossible to develop

② a large number of bubbles are generated in the glue solution, resulting in bubbles or sand holes in the layout

for the N version, when the room temperature is lower than 2O ℃, the following problems will occur:

① uneven thickness of the scraping glue will cause difficulty in developing or not showing:

② sand holes appear in the layout, resulting in slurry leakage during the printing process

the result of this test is relatively accurate. ③ the layout is uneven, resulting in inconsistent color of printing lines

2. Temperature in the oven

according to the drying temperature determined by the respective performance indicators of the plate making materials, the test should be carried out gradually from the lower limit of the specified range according to local conditions, and the best drying temperature should be selected. Generally, n version is dried without blowing; When drying f or D version, add air blast to speed up the volatilization of water in the layout and dry the layout as soon as possible

if the drying temperature is too high, the following problems may occur:

① it is difficult to develop, resulting in haze; Or not obvious

② the silk loses elasticity, resulting in the distortion of printing patterns

if the drying temperature is too low, it is necessary to extend the drying time. Otherwise, the panel cannot be fully dried. The wire edge of the sensor shall not be short circuited. For version F and D, the film or adhesive layer will fall off during development; For the N version, the adhesive layer is also easy to be thinned during development, thus shortening the service life of the printing plate

3 will have a severe impact on the results. The temperature in the exposure box is very easy to be ignored. Often the drying temperature is well controlled, and due to the temperature in the exposure box, the plate making will eventually fail

the temperature in the exposure chamber depends on the type of light source. If it is a cold light source, closing the oil delivery valve may not be considered generally; Special attention shall be paid if the radiation of the light source is strong, such as high-pressure mercury lamp. Because the high-pressure mercury lamp cannot be ignited instantly, the method of continuous exposure of several plates is usually used. In this way, the surface temperature of the printing plate at the time of exposure can reach more than 85 ℃. This temperature is extremely unfavorable to the F, D and N plates. It will cause similar problems as the development difficulties caused by the high temperature in the oven, which will seriously affect the quality of the printing plate. Therefore, an exhaust device must be installed in the exposure box to reduce the surface temperature of the printing plate. Generally speaking, the surface temperature of the printing plate cannot exceed the drying temperature

4. Developer temperature

development: it is the last condition for making a printing plate. When it is difficult or impossible to develop due to the careless operation of the previous process, the method of increasing the developer temperature is often adopted to speed up the development. The developer temperature should be controlled. Generally, the upper limit should be the drying temperature

if the temperature of the developer is too high, the following problems are easy to occur:

for version F and D, it is easy to cause the layout to swell and serration around the pattern

for version n, it is easy to make the edge of the pattern hairy and produce pattern deformation

(to be continued)

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