What are the performance requirements of the mesh and the selection of the screen?
In any printing mesh application, the extension properties of the screen are critical, and different extension characteristics, even for the same material, will have different screen strengths, screen stability and other properties. There are also different printing effects. Therefore, the extension characteristics of the screen determine the strength, stability, stretching method and quality of the screen.
1. The extension characteristics of the screen directly affect the following conditions: a. The ultimate tension of the screen, the registration and dimensional stability of the printed image;
b. the size of the mesh distance and the separation behavior of the screen and the substrate at a low grid distance; c. the adaptability of the article to be printed, especially if the substrate has an uneven or irregular surface
2, select the performance requirements of the screen: A. select the screen extension characteristics suitable for the printing parameters; B. the wire diameter is uniform, the thickness of the mesh is uniform, the opening size is uniform and square; C. is better with the emulsion or Good bonding strength; D. High tensile strength, good resilience, strong abrasion resistance; F. Good stability, little influence by temperature and humidity; G. Screen resistant to chemical solvents and chemicals.
3, the main technical parameters of the screen: A. mesh: refers to the number of mesh per cm or per inch length, 1 mesh / inch = 2.54 mesh / cm; B. wire diameter is the diameter of the woven wire mesh It is the value measured by the production plant on the screen projection plane. Usually expressed in d, the unit is: micron.
4, opening size (hole width): refers to the space between the two diameter lines (or wefts) adjacent to the screen, usually expressed in W, the unit is micron. The screen opening determines the maximum size of the particles in the screen printing ink. To achieve sufficient ink penetration, the average particle size of the ink must be less than 1/3 of the mesh.
The screen opening affects the following points: a. reproducibility of line or dot printing; b. ink permeability of the ink; c. thickness of the printing ink layer.
5, the opening area (also known as the percentage of opening area)
A wire mesh with an opening area of 35% means that the opening area per unit area is 35%. Covered by the wire diameter, the closed, impervious area is 65%, and the open area can be used to calculate the theoretical change in ink volume.
1. Screen thickness: refers to the vertical distance from the upper surface to the lower surface of the screen. Usually expressed in D, in microns. It affects the ink flow performance of the screen and the amount of ink discharged from the web. Under the same conditions of mesh and opening, the thicker the mesh, the more unfavorable the penetration of ink.