The most commonly used wire mesh varieties are nylon (also known as nylon) wire mesh and polyester (also known as polyester) wire mesh. Wires are generally only used under certain conditions, and silk screens have been basically eliminated.

Silk screen

Silk silk screen is the first plate used for screen printing. In the past, some screen printing technology books often refer to it as crepe net, natural enamel net, silk woven wire mesh, silk wire mesh, raw silk screen and so on.

The characteristics are: strong water resistance, certain hygroscopicity, good combination with photosensitive adhesive or photosensitive film, general elasticity, easy to stretch the net, and easy to make the plate making operation. However, the silk screen has poor wear resistance and chemical resistance, is easy to age and becomes brittle, has a small tension value and a high cost.

At present, in the production of screen printing plates, most of the silk screen has been replaced by synthetic fiber mesh, and the amount is small.

2. Nylon (nylon) wire mesh

Nylon mesh, also known as nylon mesh, is a nylon monofilament woven fabric that is heat-treated and dimensionally stable after weaving. The plain weave can reach 380 mesh and the twill weave is larger than 330 mesh.

Features: Nylon mesh surface is smooth, ink permeability is good, and ink with high viscosity and large particle size can be used, so fine printing patterns can be obtained; using extremely fine mesh woven mesh net, suitable for painting patterns and dots of thin lines Printing; flexible, suitable softness, good adaptability to substrates, suitable for printing on bumps and curved surfaces; good tensile strength, knot fastness, elasticity and abrasion resistance, long service life; acid and chemical resistance The drug and organic solvent have good performance and are easy to regenerate, especially because they have strong resistance to alkali.

The use of nylon mesh should pay attention to the following points: Compared with polyester and silkworm mesh, nylon mesh has a large elongation, so as not to cause printing failure, the tension of the stretcher should be increased, and the shrinkage force will also become larger. Therefore, it is required to use a strong frame and stretcher; because of its low heat resistance, if the net is fixed to the frame by hot-melting method, it is difficult from the operational point of view; it is not resistant to strong acid, sulphuric acid, cresol Erosion of formic acid; UV light has a slight effect on it, and avoiding light when storing.

3. Polyester (polyester) wire mesh

Polyester mesh is also known as ester mesh.

Features: small tensile strength and strong elasticity, single-wire mesh is suitable for high-precision printing of printed circuits, thick film semiconductors, scale plates, counting plates, etc.; tensile strength, structural strength, resilience and printing durability are better. It has sufficient chemical resistance, especially strong acid resistance, strong organic solvent resistance, recyclable like nylon; low moisture absorption, almost no influence on humidity; heat resistance higher than nylon; The effect is smaller than nylon.

Pay attention to the following points when using: polyester mesh has good dimensional stability and is suitable for high-precision printing. Therefore, nylon mesh needs to have more stretch tension, and requires stronger frame, stretcher and more. Strong bonding method; polyester is hydrophobic, it is difficult to bond with the film, pay attention to washing and degreasing before plate making; although low hygroscopicity, it is not resistant to boiling water for a long time; Nylon is slightly poor; not resistant to strong alkali corrosion.

4. Stainless steel wire mesh

Stainless steel wire mesh has excellent plane stability and stable pattern size. It is suitable for printing high-precision circuit boards and other products; excellent ink passing performance; good alkali resistance and tensile strength; excellent chemical resistance; Strong, suitable for printing of hot melt printing materials (heating on the screen to melt the printing material). The disadvantage is that it is susceptible to external bending and damage, and the wire is slack due to pressure during the printing process, which affects the printing durability, is expensive, and has high cost.

5. Nickel-plated polyester mesh

The nickel-plated polyester mesh is made by plating a layer of nickel material having a thickness of about 2 to 5 μm on the polyester web. It combines the length of both metal mesh and polyester mesh, and can produce a high tension, low elongation screen, which avoids the slack caused by metal fatigue due to metal fatigue and the low adhesion of polyester mesh to the film. Wear resistance, electrical conductivity and resilience have all improved. Therefore, the applicability of such a network is very wide. The braided joint of the net is fixed by nickel plating, the mesh is not easily deformed during printing, the ink flows smoothly, and the printed ink layer is even and thin.

The disadvantage of this type of net is that it is less resistant to the oxidizing solution used for stripping; the price is higher than that of the polyester mesh, but it is cheaper than the stainless steel wire mesh.

6. Flatten the screen

The flattening screen is made by flattening one side of the screen. The screen can reduce the amount of ink transfer, thinner the ink layer, and prevent ink from penetrating and spreading, and is particularly suitable for ultraviolet curable inks. The thickness and opening of the flattened screen are reduced by flattening, so only a small amount of ink can be used for printing. Flattening the screen is very beneficial for improving ink printability, reducing ink throughput and saving ink. Since the sectional shape of the flattening screen is deformed as shown in Figs. 2-3, it is considered that due to such deformation, the wear of the squeegee is reduced, the transmission force of the ink is enhanced, and the stencil is protected.

7. Anti-static screen

The use of a synthetic woven fabric such as nylon or polyester is easy to carry static electricity, which is a big disadvantage. Although there are a variety of methods to prevent charging, they are not perfect, especially when drying, some substrates cannot completely remove static electricity. As shown in Figure 2-4, the anti-static screen is used to make the horizontal wire conductive. The core contains carbon filaments, which is very effective in eliminating static electricity.

8. Colored screen

When exposed in the screen printing process, a halo phenomenon often occurs, and unnecessary reflected light causes exposure defects.

The reason for this phenomenon comes from the disordered reflection of the wire as the wire mesh material. Therefore, it is only necessary to avoid the occurrence of disordered reflection and to absorb the scattered light. Therefore, a colored screen is generally used.

Exposure generally uses an ultraviolet light source, but is also mixed with visible light. The color tone of the dyed screen is preferably light, and the dark color is required to extend the exposure time.

9. Nickel foil perforated net

Nickel foil perforated mesh is a high-tech wire mesh. It is not a woven mesh, but a foil mesh, which is formed by drilling a nickel foil, and its hole is hexagonal, and can also be formed into a circular hole shape by electrolytic forming. The entire mesh surface is even and thin, which can greatly improve the stability and precision of the print, and is used for printing high-tech products such as conductive inks, wafers and integrated circuits. Can distinguish 0.1mm circuit line spacing, positioning accuracy up to 0.01mm.

10. Striped wire mesh

This is a kind of wire mesh designed for the shortcoming of the lack of elasticity of the stainless steel wire, that is, a flexible edge is arranged around the steel mesh with a special elastic material, and the image area is distributed in the range of the steel mesh.