1.Screen structure and number:
For example, 120-34 means 120 grid lines per centimeter, and each grid line has a diameter of 34um.
The number of grids is the number of threads per centimeter for Polyester mesh.
The mesh size of different weaving methods is inconsistent, which determines the ink penetration of the printing plate (ink penetration is an important factor determining the printing effect).
2.Screen aperture ratio
The maximum size of the particles in the screen printing ink (the average size of the Polyester mesh printing ink must be less than 1/3 of the mesh).
Precision of printed lines and dots (too many small holes will leak ink).
Ink peeling properties (for example, larger ink particle sizes cause screen clogging and affect ink penetration during the next print)
The thickness of the ink layer (the opening is too small and the ink transmission is too small to obtain a thick ink layer)
3.Standard stretching process
The screen can be stretched to the desired tension value in 1-3 minutes, but before fixing the screen to the frame, you must wait more than 15 minutes and then increase the tension to the final tension value. If this process is repeated several times, future tension losses will be reduced.
If you stay for 5 minutes after pulling the mesh, the tension loss exceeds 28%.
If you stay for 15 minutes after pulling the mesh, the tension loss is 15-20%.
If you stay for 30 minutes after pulling the mesh, the tension loss is reduced by 10%.
The above tension loss refers to the tension loss immediately after the grid is pulled by the glue, not the tension loss after the grid is left for 24 hours. Overprinting generally stipulates that the minimum requirement is to pull the screen for 24 hours before printing, otherwise, overprinting or line distortion may occur.
After the screen is pulled by tension, the printing screen should be fixed on the screen frame, and the tension is determined by the resistance of the screen frame (that is, the maximum tension). Screen tension is an important factor to ensure the accuracy of screen printing and determine the screen spacing.
In general, the higher the number of meshes, the thinner and tighter the wire.
The standard wire mesh has a tension loss of 15-20%.
4. If tension loss is severe, you should know the following reasons:
The aluminum used in the grid is very fragile and cannot withstand greater tensile forces.
The screen is not properly placed in the machine head, and the tension on all sides is not consistent.
The tension of the side net chuck is uneven, and the net frame is placed unevenly.
Not enough time to wait and then pull the mesh.
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