Silk screen plate making

Screen plate making is the basis and key process of screen printing.If the plate making quality is not good, it is difficult to print high-quality products.Problems and defects in printing are often related to platemaking technology and material selection.Therefore, in order to make high quality screen plate, we must correctly master the plate making technology and strictly select the plate making materials according to the plate making process requirements.

Screen is the production of printing plate skeleton, is the substrate supporting photosensitive adhesive or film.Understanding the characteristics of screen and choosing the right screen according to the printing requirements is the key and primary problem to create high quality screen printing products.

1. Various applications of screen

At present commonly used types of screen nylon (also known as nylon) and polyester (also known as polyester).A strand of wire mesh is used only under certain conditions.Real screen has been basically eliminated.

Nylon mesh: is woven by synthetic fiber (polyacyl fiber), it has a good resilience, ink through the good, can withstand a certain degree of alkaline solution, wear resistance and tensile strength, high strength, the use of static electricity is small, low price, so in screen printing has been widely used.The main disadvantages are as follows: poor acid resistance, high elongation, large tensile deformation, brittle netease silk exposed to sunlight for a long time, resulting in reduced strength, and vulnerable to humidity and poor dimensional stability.

Polyester screen: woven from synthetic fiber, the high temperature resistance, chemical resistance of this kind of screen is better than nylon mesh, low elongation.Good dimensional stability, has a good tensile strength, can withstand high tension, off the screen and ink stripping the best, with the use of its tension reduced moderately, long service life, the price is relatively cheap (more expensive than nylon mesh).Polyester silk mesh overprinter with high accuracy and stability is an ideal material for making precise image printing.It is preferred to print graphics with higher dimensional accuracy.It is also the preferred screen material in optical disk screen printing.

In addition, there are stainless steel wire mesh.Excellent plane stability, the production of graphics dimension stability.Suitable for printing of electronic circuit board.Polyester screen plated tweezers have the characteristics of polyester screen and metal screen.Not easy to generate static electricity and dead creases, but small mesh, high cost.

2. The geometry of the screen

The basic elements of mesh geometry are mesh size and mesh diameter.Mesh number refers to the number of threads per centimeter.Mesh diameter refers to the calibration value of mesh diameter before weaving.

For example, the screen representation method PET1000 150-31Y Pw.That is, the screen is polyester screen (1000 is its quality/model), mesh number is 150(line/cm), silk diameter 31 U, yellow flat weave type.

Wire mesh weaving type refers to the wire mesh warp and weft cross each other in the form of woven code, flat weave namely 1:1 weaving, code for PW.There are many types of skew weaving: 2:1, 2:2, 3:3, and TW.

Screen opening refers to the space between two adjacent longitude and latitude lines, perpendicular to the screen plane and measured.Screen opening determines the maximum size of particles in screen printing ink.In order to fully penetrate ink, screen printing ink particle size must be less than 1/3 of the mesh.Screen holes affect: line and dot printing level of fine, ink stripping performance.The thickness of the printing ink layer.

3. Screen selection should be based on the following factors:

1) The smaller the diameter of the mesh, the larger the relative opening area, so it is more suitable for the replication of fine layers.

2) The finer the mesh, the worse the corrosion resistance of the corrosive cleaning agent, during printing, the worse the abrasion resistance of the ink anti-scraping board.

3) The larger the diameter of the mesh.The smaller the relative opening area is, the more difficult it is to reproduce fine lines and small dots.

4) The larger the diameter of the screen screen, the higher the printing resistance.

In general. In addition to considering the above factors, screen selection should also consider the ink, substrate surface adaptability.The service life of the template, production cost and other factors.Only after comprehensive consideration, can the right choice of screen, help to achieve the best printing effect and economic benefits.

The commonly used screen cloth for optical disk screen printing is as follows:

1) Choice of white background: 40-31YPW 140-34YPW 150-31yPW

2) Selection of color blocks :140-31YPW 140-34YPW 150-31yPW

3) Choice of fine lines: 165-31yPW 150-31yPW4) Choice of dot printing: 165-31yPW 150-31yPW

180-27YPw

5) The choice of large particle ink 140-31YPW or even less days 6) the choice of special thickness requirements: 120-34yPW