The silk screen printing process is that the ink passes through part of the mesh of the screen and then leaks on the substrate, while the rest of the mesh of the screen is blocked and the ink cannot penetrate. When printing, the ink is poured on the screen, and the ink will not leak through the mesh to the substrate without the effect of external force, but when the scraper scrapes the ink with a certain pressure and inclination angle, it will be transferred through the screen Go to the following substrate and complete the imitation of the image.

Precautions for stretching the net

1) Related parameters

In screen printing machine printing, the mesh size, wire diameter, screen weaving method and selected raw materials directly affect the tension of the stretched net. When stretching the net, the tension of the screen is measured according to these parameters. , When measuring the tension, the detected tension point should be 10 cm away from the inner edge of the screen frame, otherwise the measured tension is inaccurate.

2) Tension value

The maximum tension value referred to by the tension is the display of the specific wire mesh strength, that is, the maximum tension value that can be accepted and rebounded by various meshes and different wire diameters. If the tension value exceeds a given value, the mesh will lose Elasticity becomes plastic deformation, which should be paid attention to in stretching.

3) Warp and weft tension

The unit of tension: Newton/centimeter (N/CM), which can be measured with a Newton tensiometer. The tensiometer can measure the warp and weft tension. The so-called warp tension of the screen is the tension in the winding direction of the whole roll of screen, that is, the tension in the edge typing direction; the weft tension of the screen is the tension in the width direction of the screen.

4) Screen material and diameter

The same raw material produces different wire diameters and meshes with different meshes. The tension is different. It is the same mesh mesh. The tension is different. Different, the tension is different, because the degree of tension is proportional to the diameter of the mesh.

Precautions when coloring ink

1) Choose the principle from light to dark, no matter you prepare light or bright color ink, when the hue is close to the model, you should be careful. It is best not to mix and use inks produced by different manufacturers. Try to use inks of different colors from the same manufacturer for color mixing, otherwise uneven color tone will occur, and in severe cases, cohesion will occur and the ink will be useless.

2) When mixing inks, try to add as few inks of different colors as possible. Generally speaking, the less types of colored inks are used, the better the mixing effect will be.

3) Some screen printing inks are dried by drying. Light colors are lighter than undried ones, and dark colors are darker after drying. In addition, whether the color tone of the ink is different before and after drying during printing is a problem that is easily overlooked. Generally speaking, after natural drying (solvent volatile ink), the substrate is plastic, metal, paper, glass, etc., and the color will not change; but if it is a color material for ceramics, the color will not appear until after burning and oxidation. , can only be adjusted by experience. As for the screen printing inks that are dried by heat-setting and light-setting, the color changes in shades. When the amount of ink adjustment is large, the ink adjustment machine can be used to complete the color adjustment in a short time.

Silk screen skills and characteristics

1) Screen printing can use many types of inks. That is: oily, water-based, synthetic resin emulsion, powder and other types of ink.

2) The layout is soft. The screen printing layout is soft and has a certain degree of elasticity, not only suitable for printing on soft items such as paper and cloth, but also suitable for printing on hard items, such as plastic, glass, ceramics, etc.

3) The printing force of screen printing is small. Because of the low pressure used in printing, it is also suitable for printing on fragile objects.

4) The ink layer is thick and the covering power is strong.

5) It is not restricted by the surface shape of the substrate and the size of the area. As can be seen from the foregoing, screen printing can be printed not only on flat surfaces, but also on curved or spherical surfaces; it is not only suitable for printing on small objects, but also suitable for printing on larger objects, with great flexibility and wide range. applicability.

Printing elements of screen printing machine

1) Silk screen printing plate

Three methods can be used to make screens for screen printing machines: direct coating method, direct film pasting method, and direct film pasting method. According to the type of substrate, important parameters such as screen tension, screen mesh number, plate film thickness, and screen frame size should be fully considered during the plate making process. Choose water-based or oil-based photosensitive glue according to the type of ink.

2) Screen printing ink

Screen printing machines can use solvent-based screen printing inks, UV screen printing inks and various functional pastes. Screen printing inks should be selected and tested according to the material of the substrate.

3) Screen printing squeegee

The screen printing squeegee is the pressure source of the screen printing machine, which plays the role of transferring and leaking ink. Flat substrates generally use a squeegee with a rectangular cross-section, and curved substrates generally use a squeegee with a triangular cross-section. For CD discs, special squeegees can be considered. Soft squeegee is used for rough surfaces, and hard squeegee is used for smooth surfaces. Squeegee.

4) Fixtures

Fixtures with good stability and uniformity must be made to ensure the accuracy of overprinting and the consistency of orientation. The tangent plane of the highest point of the plane fixture is parallel to the screen plane, and the curved surface fixture requires that the diameter of the transmission gear index circle at the shaft end is equal to the diameter of the circular surface of the substrate.