Study on exposure test of flexographic resin plate

2022-10-16
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Research on exposure test of flexographic resin plate made by point light source II

exposure test

we have done a series of exposure tests with point light source exposure machine and general exposure machine to answer this question: where? How about the exposure processing of flexographic plate and the printing effect after exposure processing with point exposure equipment in the environment

is the test material selected? Multi print equipment providers and flexographers use 1.14mm thin flexographic plates recommended by customers, which are suitable for point light printer. We use the depth of the pictures and texts exposed between 0.6 and 0.7mm to make? Requirements for this print

to realize the main exposure of ideas on the printer, we test and adjust step by step according to the following sequence:

light intensity

scattered light

length of exposure time

firmness of point area (based on the firmness of 120 lines at 1% and 2% points)

firmness and width of independent existence? 0.1mm straight line or diameter? 0.1mm point reproduction

width? Reproduction of 0.08mm anti white line depth

evaluation of test results

image shape and its firmness

to ensure that all factors to be tested can be clearly exposed, the point light source exposure machine is required to expose the printing plate with the highest light intensity and at least astigmatism of more than 50%. It is extremely unscientific to evaluate the exposure results only by eyes, especially the sharp points. Because? The resolution of human eyes is limited. If a small point is not amplified, we can't see its shape at all. In fact, the dots on the printing plate should form a solid bond with the foundation at the beginning, but it leads to the inclination of the dots and the reduction of the firmness of the edges of the dots. These phenomena can be clearly seen only under the electron microscope

drying the independent positive image on the flexographic plate is an important means to evaluate the advantages and disadvantages of the printing plate. People often use width? 0.1mm male line. For highly sensitive printing plates, the main exposure time is about 20 minutes, that is, not? The waviness of the positive line cannot be removed even if the exposure time of 45 minutes is used for the printing plate with low photosensitivity. In general, the stability of fine positive line image on a plate printer depends on the type and location of adjacent elements. At the edge of the printing plate, if there are other images, its firmness is relatively strong. But if only one exists, then? It will lose its partial firmness. For the point or positive line in the middle of the printing plate, they are strong with the foundation

exposure tolerance

in the field of flexo plate making, people stipulate that the lower limit of exposure tolerance: the number of lines added? 2% of the points in the

point area of line 120 can be exposed, that is, the width? 0.1mm male thread can be exposed. Its upper limit is width? The 0.08mm anti white line can reach the pre-defined depth. Although this is the standard set before, it is still used in light source printer? Basis for evaluating exposure tolerance. The purpose of our test is to prove that we can not only ensure the perfect reproduction of thin lines, but also ensure that the reproduction quality of the original anti white lines is not lost

in the process of point light source printing, it clearly shows that the soft exposure tolerance is small, or even no tolerance exposure. They usually show? Width? The 0.1mm straight line is strong enough, but the depth of the depression is not enough or the line definition is not enough. The instability of photosensitivity of printing plate materials, the complexity of printing plate images and the instability of film quality will affect the exposure process and exposure tolerance? Have a significant impact.? As we all know, the sharp points on the printing plate alone are higher than the surrounding full plate. This may be caused by the heat balance principle and circular mixing method used by the material expansion caused by the incomplete exposure of the tip and the substrate. Increasing the amount of scattered light or "prolonging the exposure time" can make the sharp points obviously firm

in order to make the exposure tolerance play a full role, we have tried to use UV filters to filter out the unwanted UV components in the emission spectrum of the point light source. Unfortunately, the luminous intensity of the light source is reduced while removing the UV component. Therefore, this idea cannot work

printing plate edge

there is a point tilt at the edge of the printing plate, which seems to be a common headache when using a point light exposure machine, and this tilt angle is surprisingly consistent with the incident angle of the incident light. When the exposure is insufficient, the inclination angle of the points on the printing plate is disordered, while when the exposure is normal or overexposed, the inclination direction of the points on the printing plate points to the light source. This phenomenon is caused by the light emitted by the point light source shining obliquely on the edge of the printing plate rather than vertically. People can use mirrors to correct this phenomenon, but the cost is relatively high, so the actual production? Not used in

summarize that China's annual output of steel accounts for 1.5% of the world

although the point light source exposure equipment can be sensitive to the vast majority of flexographic resin plates, it has the following obvious shortcomings compared with the general traditional exposure equipment:

this exposure machine is of certain significance for flexographic plates with small format and relatively thin thickness. For the drying requirements with a depth of

greater than 0.6mm (using a longer exposure time can be achieved, but we found that the middle depth is relatively poor), considering that we want to achieve a sufficiently steep point with good industrial prospects in the field of new materials, we accepted the proposal of the point exposure equipment provider to use 40% astigmatism. Unfortunately, it is found that the depth cannot exceed 0.5mm

insufficient resolution of the printing plate (because the points have a certain tilt angle and the thin lines are wavy, the reproduction of fine points lacks stability)

the replication result is not ideal and the format is limited. In point exposure equipment, the quality of the film, the image of the plate on the film and the photosensitivity of the printing plate material all affect the printing reproduction results? Have a great impact. The position of the light source relative to the plate material sometimes affects the shape of the point

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