Mesh is the basis for screen plate making, screen mesh quality directly affects the quality of the screen plate, screen mesh choice is right or not will directly affect the final quality of screen printing. Therefore, the choice of mesh is the first problem for a successful screen printing.
1. Types and characteristics of screen mesh:
The commonly used screen mesh usually includes three categories according to material, nylon, polyester, and stainless steel. The polyester screen mesh is divided into three: There are ordinary polyester mesh, high tension low-stretch polyester mesh, and one-side flat mesh. The classification can be illustrated with a simple diagram as follows:
Screen Printing Mesh
Nylon Mesh ----Ordinary polyester screen
Polyester Mesh----high tension, low extension
Stainless Steel Mesh----single sided pressing flat-screen
Polyester screen mesh. Besides, there is some professional use of the screen mesh. Such as anti-static Wire Mesh, Glass Special Polyester Wire Mesh, Ceramic Special Nylon Wire Mesh, and so on. The following is a brief description of the following 5 kinds of screen performance.
Nylon Mesh: Woven from polyurethane fiber (commonly known as Nylon), with the advantages of polyurethane fiber. That is:
A. It has good resilience and high elasticity
B. Superior abrasion resistance, suitable for long-form printing
C. The surface is smooth and has a good ink-passing property
D. Good surface tension properties, strong tensile strength
E. Not easy to produce static electricity, a certain degree of Alkali Resistance
The disadvantages of Nylon Mesh are as follows:
A. Poor resistance to direct ultraviolet or strong light
B. Poor acid resistance, affected by temperature and humidity, poor dimensional stability
C. High Elongation rate and large deformation affect the accuracy of overprint
2. Plain Polyester Mesh: Woven from plain polyester fibers. The advantages are:
A. High tensile strength, able to withstand higher tension
B. Good wear resistance, can offset the ink in the printing ink and squeegee wear on the screen.
C. High Light Resistance under natural room-temperature light. Long Shelf Life
D. Insensitive to climatic factors, low hygroscopicity, and strong heat resistance
E. Low elongation and good dimensional stability
F. Strong chemical resistance, resistance to acid in general, but resistance to Alkali in general limited
DISADVANTAGES OF PLAIN POLYESTER SCREEN:
With the combination of photographic EMULSIONS, ink, wear resistance is not as good as nylon. Shihan before the screen, screen pre-processing (that is, the screen needs to be roughened degreasing and grinding screen)
3. HIGH TENSION LOW STRETCH POLYESTER MESH: Woven from high tension polyester fibers. In addition to the advantages of the plain polyester screen, it also has the following outstanding advantages:
A. Its structure is more stable, tension stability is high, long-term printing operation precision stability.
B. Can withstand the very high tension, but the extension is low, enhances the overprint precision
C. In printing, the screen space is small and the screen and ink peel off well
D. Long Service Life, strong mechanical and chemical resistance
4, one-sided flat screen: Woven from polyester fiber. The polyester net is pressed against each other through a pad pressing stick and a rubber stick to form a flat side of the Silk Net. So the screen thickness of 25%, the opening area is also slightly reduced, in other processes the same, the thickness of the printing ink layer is reduced, more conducive to UV ink curing. It is suitable for UV UV curable inks, so also known as a UV screen. Its outstanding advantages are:
A. It can save about 35% of UV ink
B. Pressure plane in the ink surface, printing, scraper in a smooth screen scraping relatively smooth, screen long service life.
C. High printing clarity, good dimensional stability, can print high-quality products.
Stainless Steel Wire Mesh: Woven from stainless steel wire, with the following characteristics:
A. High tension, low elongation, excellent screen stability
B. High tensile strength, good ink-passing
C. Fine Line diameter, large aperture, and uniform line diameter opening, high printing accuracy
D. Potential Resistance Chemical Resistance, Abrasion Resistance, moisture resistance are good
Stainless Steel Mesh shortcomings: easily broken by an external force, small rebound, the price is not easy to place