How To Better Use Flat Screen Printer

Posted by lichengprintingmachine on Mai 15, 2020 in News |

Licheng is a professional manufacturer of R & D screen printing machines, pad printing machines, and various printing equipment. The following is a brief introduction about the quality improvement of Flat Screen Printer:
In addition to the choice of plate-making materials, the key to the advancement of screen printing products lies in the rationality of screen printing plate production technology. Nowadays, screen printing plates are mostly made by hand, and there is even a need for the advancement of plate-making technology.
L Selection of screen mesh
The choice of screen mesh number should be decided according to the printed pattern and the request for the pattern. If the pattern is larger and the line is thicker, and the request for the pattern is not so precise, you can choose a mesh with a lower mesh. On the contrary, if the pattern is fine and the lines are narrow, and the pattern is pleading for accuracy, a mesh with a relatively high mesh number should be used. The screen mesh number directly affects the print quality. Because the printing plate with relatively low mesh screen number has good penetrability of the printing paste, the mesh is not easy to be blocked. But the mesh number is too low, which also makes the printing material penetrate too much, which constitutes the phenomenon that the edges of the pattern are unclear and the image is distorted.
The screen mesh has a high mesh number, can reach the edge of the figure, and the line is very scratchy. However, the screen mesh number cannot be higher than the printing material mesh number; otherwise, the mesh holes are simply blocked. Therefore, you should choose a moderate number of meshes, generally between 120 meshes and 300 meshes. You can use the bisection method in the single-element advantage selection method to make a selection test.

2. Stretching the net
When the wire mesh stretches the frame, the tightness should be appropriate, and pay attention to the same tension at each point in the frame. If the wire mesh is stretched too tight or too loose, or the tension at each point is inconsistent, the following questions may occur:
The screen is stretched too tightly: to make the printing plate screen lose its elasticity, and the image is distorted during printing; the screen is stretched too loose or the tension of each point is different: ①Precision lines cannot be developed; ②The edges of the pattern appear jagged, Distorted graphics; ③The phenomenon of slurry leakage occurs during the printing process; ④For the F version, the adhesion between the film and the screen is poor, which constitutes the phenomenon of the film falling during development.

The quality of the printing plate is related to various temperatures during the production. This temperature includes: 1. The temperature in the operating room; 2. The temperature in the oven; 3. The temperature in the exposure box; 4. The temperature of the developer.
L Operating room temperature

Operating room temperature should generally be kept at 25 ℃. In winter and summer, pay attention to the scheduling and control of temperature. For version F, the effect of room temperature is not obvious. For version D, in hot climates, if the room temperature control is not good, the following questions will occur:

①It is easy to make thermal cross-linking when making glue, which makes it difficult or impossible to develop; ②There are many bubbles in the glue, causing bubbles or trachoma on the layout. For the N version, when the room temperature is lower than 2O ℃, the following questions will occur: ① The uneven thickness of the squeegee constitutes a difficult or undevelopable development: ② The appearance of the screen is blisters, which constitutes the phenomenon of slurry leakage in the printing process; ③ The page is not Flat, the color of the printed pattern is inconsistent.

2. Temperature in the oven

The drying temperature determined according to the performance indexes of the plate-making materials should be preliminary and gradually tested from the lower limit of the rule plan according to local conditions, and the best drying temperature should be selected. Generally, drying the N version does not add blast; drying the F or D version needs to add blast to accelerate the speed of the volatilization of the plate surface, and quickly make the plate monotonous. If the drying temperature is too high, the following questions may occur:

① Difficult to develop, with haggle; may not show up; ② The silk screen loses its elasticity, causing the printed patterns to be distorted.

The drying temperature is too low, and the monotonic time must be extended, otherwise the layout cannot be fully monotonic. For the F and D plates, the film layer or adhesive layer will fall during development; for the N version, the adhesive layer is also easy to be thinned during development, and then the service life of the printing plate is shortened.

The process of making a printing plate is a messy physical and chemical process involving many elements. In addition to the above elements, there are the luminosity during exposure, the humidity in the process of plate making, and so on. Especially in the plate-making process, many processes are manual operations, and many elements are directly controlled by people. Therefore, in the production process, many elements cannot be measured accurately. For example, the thickness of the squeegee is difficult to measure during operation. Therefore, it can not be determined specifically how long it can be dried; for another example, how thick the film layer after squeegee is, how long should the exposure time be It is added incrementally, but it is obtained after repeated experiments!

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