introduction
The stencil printing with the screen material as the printing plate support body is called “screen printingâ€. Screen printing technology is called “screen printing†in the printing industry and “silk screen printing†in the textile printing and dyeing industry. Although both are "SCREEN PRINTNG" in English, their industry habits are often very clear and they are not easy to change. The prominent commonality between "printing" and "printing" is "printing." Although there are many differences in their production process equipment and printing materials, the basic principles of "printing" and the material of printing plates are similar or consistent. of. Because screen printing covers a wide range of areas and is distributed in all walks of life, the types and varieties of production and processing are difficult to count; at the same time, due to the barriers of the industry, there is a lack of communication for a long time, so its development has certain stages, and the silk in different industries. There are also many gaps in the development of screen printing.
Screen printing originated in ancient China and has a history of about 2,000 years. It was used for mass production of textile silk printing in the mid-1950s. The industrial production of "screen printing" developed late and started in the late 1970s and early 1980s. "Screen printing" covers a wide range of areas. This article will focus on textile screen printing, introducing screen printing applications, technical characteristics and textile printing technology.
Screen Printing Application Profile
As a screen printing of professional processing technology, the industry boundary is clearly divided during the planned economy period. After the reform and opening up, this boundary was gradually broken down. Various industries applied screen printing to related products, thus forming a special industry shared by all walks of life. Its characteristic is that the company is small in scale and very dispersive, and it can be roughly summarized as the following aspects.
1) Needle textile screen printing. The data show that in the international silk screen printing industry, textile screens account for more than 50% of the total, which relates to clothing, accessories, bedding, interior decorations, hygiene products, shoes, caps, etc., as well as flags and promotional materials in people's daily lives. .
2) Circuit board and membrane switch. It is a rising star of silk screen printing. China began to develop it in the 1960s. With the rapid development of the electronics industry and the increase and innovation of applied components, the industry has developed rapidly and it has a wide range of coverage. Electronic products are inseparable from screen printing.
3) Plastic products. Including soft plastics and hard plastics, common children's toys, packing bags and daily commodities and some containers, such as bottles, cans, boxes and so on.
4) Screen printing of the packaging. Its variety of materials, various types of regulations, there are paper, wood, synthetic materials, but also metal and plastic, a wide variety.
5) Large-format advertisements and posters. In the past, general posters were based on offset printing. The pattern was bright and colorful, with rich tone levels, but its print area was limited. At the same time require a larger amount of print. Screen printing can make up for its weaknesses, suitable for small-volume printing, and large-format screen printing breaks the limitations of offset printing format. Although the application time is not long, it is developing rapidly.
6) Ceramic decals and transfer paper. Their history is about 20 years. The former is affiliated with the ceramic industry. The latter has a diversified application field due to the diversification of transfer techniques.
7) Signage, Nameplates and Cards. By printing on the surface of various materials, such as metal, plastic, and wood, words, patterns, symbols, lines, etc. are printed on the surface, and various types of signs and cards are made. The printing techniques are various and the products can be seen everywhere.
8) Screen printing in the field of fine arts. European and American countries divide screen printing into two categories: industrial screen printing and art screen printing. China's fine arts screen printing is also actively developed, but it is still not widely used.
Screen printing is also widely used in glass and leather decoration. Anti-counterfeiting ink printing anti-counterfeit labels and optical disk printing also adopt screen printing technology.
Common points and differences
No matter which industry is used for silk screen printing, all kinds of screens are used as the carrier of the film, but there are some differences in the selection of the screen and the plate making process. This article only deals with textile screens from several aspects. A slight comparison is made between printed and non-textile screen printing for reference.
1. Prepress processing
1) Textile screen printing. Pattern design, description of black-and-white color separation (ie, positive film), and general photolithography of continuous shooting process, in addition to an independent flower shape, the main manual operation, high technical requirements for workers, lower work efficiency. Photographic materials need to use waterproof type.
2) Non-textile screen printing. The pattern is generally completed by photography or scanning, and the color separation is mostly based on four colors. Most of the printing patterns are independent, and there is no process of joining plates. The photosensitive material is mostly solvent-resistant.
2. Wire mesh material
It is the main material of screen printing. The screen weaved with silk has long been replaced by nylon screen. Nylon screen has high strength, wear resistance and elasticity, but it is susceptible to changes in temperature and humidity. Affecting the accuracy of the layout, polyester (polyester) screens are commonly used when printing high-end products. There are also wire meshes, such as nickel nets for rotary screen printing and stainless steel screens for circuit boards. There are a wide variety of screen sizes, ranging from 36 to 90 inches in width and from 80-500 mesh/inch, depending on the application.
3. Screen printing equipment
Silk screen printing equipment is very complex, from simple family workshops to modern complete sets of equipment, there is a big gap, here only a brief distinction.
1) The screen printing of textiles is divided into circular nets and flat nets. Flat net equipments include printing platen, automatic flat screen printing machine and rotary printing machine. The maximum width of the automatic flat screen is 3.2m, the length is about 60m, and the maximum color is 24 colors, which belongs to large equipment. The screen printing of textiles is generally continuous printing, even the handkerchiefs and tablecloths with independent patterns are also printed after continuous cutting. In fact, garments and T-shirts are mostly printed on rotary screens.
2) Non-textile screen printing equipment is more complicated, because of different substrates and has a unique printing method and special printing effect, according to the printing object to choose printing equipment. In general, there are desktop manual, semi-automatic, fully automatic flat screen printers and drum type, curved surface, and three-dimensional printing machines, and there are many special equipments, and the gap between the sizes of printing areas is also large. Their common feature is the independent printing. The main method is (ie, one workpiece and one workpiece are printed separately).