How to Use Offset Screen Printing to Create New Ideas in Offset Printing (I)

1. Overview of silk screen

The screen-printed printing plate is in the form of a net, and the ink on the printing plate is squeezed downward by the squeegee during printing, and is printed on the printing material from the through-hole portion of the plate. The change of screen printing effect mainly depends on the screen design and materials, ink properties and so on.

Screen Design and Materials

The size of the mesh affects the fineness of the silk screen. The finer the mesh, the more suitable it is for printing detailed images. Now meshes are usually made from 63 to 150 metrics, but rarely more than 150. In addition to the technical limitations of mesh materials and manufacturing screens, it is more important that the inks also have a certain viscosity, so the larger meshes (ie meshes) Finer, it is often difficult for ink to pass through the mesh. In addition, many silk screen products require a thicker layer of ink to express the texture of the printed matter and to exploit the ink's specialty. When printing such products, finer meshes and appropriate inks should be used.

Silk screen printing ink

Screen printing ink is mainly divided into two kinds of thermosetting and UV curing. Thermoset inks are more choices and the cost is lower. However, the thermosetting ink layer may volatilize. Therefore, if there is not enough ink to wet the screen during the production process, or if the paused printing time is too long, there will be inevitably a plug-in condition, and the thermosetting ink will take a long time. Only thoroughly dry. Therefore, with regard to the convenience and effect of production, thermosetting inks are not UV curable inks.

In recent years, UV-curable inks have become more and more popular in screen printing. In addition to avoiding plugging problems, it is more important that they can be dried in a short time. In today's environment where productivity and efficiency are important, UV curable inks solve many problems for them. In addition, UV inks can produce printing effects that cannot be achieved by some thermosetting inks. For example, some UV inks can receive different burst patterns when receiving different wavelengths of UV light, namely, so-called special moiré patterns or ice pattern effects. UV inks are most commonly found in prints, but they are partially UV-cured. Although flexible printing can also be used for local UV polishing, on the basis of texture and outstanding image performance, screen printing UV glazing is undoubtedly superior.

2. Differences between offset printing and screen printing

The basic principle of offset printing is that "oil and water are not kinship." Use this principle to make related PS plates. Ink, transfer printing through a blanket, is a simple printing method. There are many kinds of offset printing methods (water printing, waterless printing, flat pressing, round pressing, etc.), and the requirements for substrates and related consumables are relatively strict.

Screen printing is direct printing. Printing is performed by miss printing. The effect of printing is controlled by the thickness of the mesh of the screen, the hardness and hardness of the squeegee, and the angle pressure. There are various printing methods (flat circular roller type, round pressure Circular, flat and flat, and unconventional shapes, etc.) The range of substrates and printing consumables is very wide.

Traditionally, Offset Printing has a large amount of production and investment, and most of the fixed equipment is less adaptable to printing materials, so it is generally necessary to “print materials to relocate machines”. Silk screen printing, on the other hand, has lower production efficiency and lower investment in general equipment. Different types of printing materials such as paper, film, and fabrics can also be used. Therefore, it is "machine-adapted to printing materials." Screen printing products include a wide range of products, such as pressure gauges, matte patterns on tobacco and alcohol boxes, ceramic flower paper (paper pattern transferred to the ceramic), general print (local glazing), electronic products (nameplate and flexible Lines), ironing drawings, etc.