Small batches of woven bag printing are printed by silk screen printing, while large batches are printed by gravure printing. Gravure printing requires special machines and related professionals, and the investment is huge. The following will introduce you to the silk screen printing method. Screen printing: Screen printing is to stretch silk fabric, synthetic fiber fabric or metal mesh on the screen frame, and use hand-engraved paint film or photochemical plate making method to make the screen printing plate. Modern screen printing technology uses photosensitive materials to make screen printing plates through photographic plate making (so that the screen holes in the graphic and text parts of the screen printing plate are through holes, while the screen holes in the non-graphic and text parts are blocked. live). During printing, the ink is transferred to the substrate through the mesh of the graphic part through the squeezing of the scraper, forming the same graphic and text as the original. Screen printing equipment is simple, easy to operate, easy to print and plate making, low in cost, and has strong adaptability. Screen printing has a wide range of applications and common printed materials include: color oil paintings, posters, business cards, binding covers, product signs, and printed and dyed textiles.

In terms of environmental protection, screen printing is a heavy pollution process. First of all, The plate making process produces developer, the ink used produces ink barrels, and cleaning wastewater or waste rags are produced during cleaning. Dongfang Longke Zhengsen

1. What is screen printing?

Screen printing belongs to stencil printing. It is called the four major printing methods together with flat printing, embossed printing and gravure printing. Hole printing includes transcription plates, perforated plates, spray printing and screen printing. The principle of stencil printing is: when the printing plate (a paper plate or other plate base is made with holes through which ink can pass), a certain amount of pressure is used to transfer the ink to the substrate (paper, ceramics, etc.) through the holes of the stencil. ) to form an image or text. Transcription printing is the simplest type of hole printing and began in the late 19th century. This kind of printing is done on special wax paper, using a typewriter or stylus to make a wax paper graphic plate. An ink roller is used to print on the wax paper plate, and the ideal printing effect can be obtained on the substrate. Among stencil printing, the most widely used is screen printing.

Screen printing is to stretch silk fabric, synthetic fiber fabric or metal mesh on a screen frame, and use manual carving of paint film or photochemical plate making to make a screen printing plate. Modern screen printing technology uses photosensitive materials to make screen printing plates through photographic plate making (so that the screen holes in the graphic and text parts of the screen printing plate are through holes, while the screen holes in the non-graphic and text parts are blocked. live). During printing, the ink is transferred to the substrate through the mesh of the graphic part through the squeezing of the scraper, forming the same graphic and text as the original. Screen printing equipment is simple, easy to operate, easy to print and plate making, low in cost, and has strong adaptability. Screen printing has a wide range of applications. Common printed materials include: color oil paintings, posters, business cards, binding covers, product signs, and printed and dyed textiles.

▼2. When was screen printing invented?

Screen printing first originated in China and has a history of more than 2,000 years. As early as the Qin and Han Dynasties in ancient my country, the clip printing method appeared. By the Eastern Han Dynasty, the Jiajie batik method had become widely popular, and the level of printed products had also improved. During the Daye period of the Sui Dynasty, people began to use frames stretched with silk net for printing, and the clip printing process developed into screen printing. According to historical records, the exquisite costumes worn in the palace during the Tang Dynasty were printed using this method. In the Song Dynasty, screen printing developed again, and the original oil-based paint was improved, and starch-based glue powder was added to the dye to turn it into a slurry for screen printing, making the colors of screen printing products more brilliant.

Screen printing is a great invention in China. The American "Screen Printing" magazine once commented on China's screen printing technology: "There is evidence that the Chinese used horsehair and templates two thousand years ago. The clothing of the early Ming Dynasty proves their competitive spirit and processing technology?" quot;The invention of screen printing promoted the development of human material civilization in the world. Today, two thousand years later, screen printing technology continues to develop and improve, and has now become an indispensable part of human life.

▼3. What is the principle of screen printing?

Screen printing consists of five major elements, namely screen printing plate, scraper, ink, printing table and substrate. The principle is to use the basic principle that the graphic part of the screen printing plate is permeable to ink, and the non-graphic part is impermeable to ink. When printing, pour ink on one end of the screen printing plate and use a scraper to apply it. Apply a certain amount of pressure to the ink part on the screen printing plate and move it toward the other end of the screen printing plate at the same time.

The ink is squeezed by the scraper from the mesh of the graphic part onto the substrate during movement. Due to the viscosity of the ink, the imprint is fixed within a certain range. During the printing process, the scraper is always in line contact with the screen printing plate and the substrate. The contact line moves with the movement of the scraper. Since the screen printing plate and substrate A certain gap is maintained between them, so that the screen printing plate during printing generates a reaction force on the scraper through its own tension. This reaction force is called rebound force. Due to the effect of resilience, the screen printing plate and the substrate are only in moving line contact, while other parts of the screen printing plate are separated from the substrate. It causes the ink and screen to break apart, ensuring the printing dimensional accuracy and avoiding smearing of the substrate. When the scraper scrapes across the entire page and then lifts up, the screen printing plate also lifts up and gently scrapes the ink back to its original position. This is a printing process.

▼4． What are the main differences between screen printing and other printing methods?

Compared with other printing methods, the main differences between screen printing and other printing methods are as follows:

① Strong printing adaptability. The three major printing methods of flat printing, embossed printing and gravure printing can generally only Print on a flat substrate. Screen printing can not only print on flat surfaces, but also on curved, spherical and concave-convex surfaces. On the other hand, screen printing can not only print on hard objects, but also print on soft objects, and is not limited by the texture of the substrate. In addition, in addition to direct printing, screen printing can also be printed using indirect printing methods as needed, that is, screen printing is first printed on a gelatin or silicone plate, and then transferred to the substrate. Therefore, it can be said that screen printing has strong adaptability and a wide range of applications.

② The ink layer is thick, three-dimensional and rich in texture. The ink layer thickness for offset printing and embossed printing is generally 5 microns, for gravure printing it is about 12 microns, and for flexographic (aniline) printing it is 10 microns. Microns, and the thickness of the ink layer for screen printing far exceeds the thickness of the above ink layer, generally up to about 30 microns. Specially used for thick screen printing of printed circuit boards, the thickness of the ink layer can be up to 1000 microns. Use foaming ink to print Braille dots, and the thickness of the ink layer after foaming can reach 300 microns. Screen printing has a thick ink layer, rich printing quality and strong three-dimensional effect, which is unmatched by other printing methods. Silk screen printing can not only perform monochrome printing, but also perform color printing and screen printing.

③ Strong light resistance and bright color. Since screen printing has the characteristics of leakage, it can use various inks and coatings. Not only slurries, adhesives and various pigments can be used, but also Use coarser grained pigments. In addition, the preparation method of screen printing ink is simple. For example, the light-fast pigment can be directly put into the ink for preparation, which is another major feature of screen printing. Screen printing products have the great advantage of strong light resistance. Practice has shown that, based on the maximum density value range measured after one imprint on coated paper using black ink, offset printing is 1.4, embossing printing is 1.6, and gravure printing is 1.8, while the maximum density value range of screen printing can be It reaches 2.0, so the light fastness of screen printing products is stronger than that of other types of printing products, and it is more suitable for outdoor advertising and signage.

④Large printing area. At present, the maximum area printed by offset printing, embossed printing and other printing methods is the full sheet size. If it exceeds the full sheet size, it is limited by mechanical equipment. Screen printing can print on a large area. Today's screen printing products can reach a maximum size of 3 meters × 4 meters or even larger.

The above four points are the differences between screen printing and other printing, and they are also the characteristics and advantages of screen printing. After understanding the characteristics of screen printing, you can maximize your strengths and avoid weaknesses when choosing a printing method, highlighting the advantages of screen printing to achieve a more ideal printing effect.

▼5. What type of original is suitable for screen printing?

Silk screen printing, like other printing, needs to accurately reproduce the graphics, text and tones of the original. In principle, the manuscripts used in screen printing are not very different from the manuscripts used in other printing methods, but in specific plate making and printing practices, the requirements are different, which is mainly determined by the characteristics of screen printing. Especially because the screen printing ink layer is thick and the color is bright, the special effects of screen printing should be fully considered when selecting original manuscripts and plate making.

In addition, the requirements for the graphic and text lines and dot accuracy of the manuscript used for screen printing are also different from the requirements for the manuscript used for ordinary printing methods. If the lines and dots of the original are very fine, it will be very difficult to use screen printing to make plates.

Therefore, screen printing technology is not suitable for reproducing original manuscripts with fine lines and dots. When selecting printing methods, the characteristics of various printings should be fully considered. Even when making screen printing plates, attention must be paid to selecting appropriate screen cables in order to fully reproduce the original manuscript.

Screen printing is more suitable for monochrome complete color manuscripts that express text and bright lines. It is also suitable for color manuscripts with large contrast and clear layers. Through the special effects of screen printing, the reproduction has rich expressive power. Through the rich and thick ink layer and the contrast of light and dark tones, the texture and three-dimensional effect of the original content are fully expressed.

There are two types of screen printing photographic plate-making originals: reflective originals and transmission originals. Reflective originals are usually mainly used. Color photography mostly uses transmission originals.

Screen printing mainly uses positive images to make screens. Different plate making methods have different requirements for the original manuscript.

▼6． What are the main characteristics of screen printing?

The characteristics of screen printing can be summarized in the following aspects:

① Screen printing can use many types of inks. Namely: oil-based, water-based, synthetic resin emulsion type, powder and other types of ink.

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

③The printing force of screen printing is small. Since the pressure used during printing is small, it is also suitable for printing on fragile shopping objects.

④The ink layer is thick and has strong coverage.

⑤ It is not limited by the surface shape and area size of the substrate. As can be seen from the above, screen printing can not only print 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. This printing method has great flexibility and wide applicability.

▼7. How many methods are there for screen printing?

There are usually two types of screen printing, namely manual printing and mechanical printing.

Manual printing means that from paper feeding to paper delivery, the up and down movement of the printing plate, and scraping and scraping are all manual operations.

Mechanical printing means that the printing process is completed by mechanical action. It is divided into semi-automatic and fully-automatic printing. Semi-automatic means that the placing and taking out of the substrate is manually operated, and printing is completed by machinery; fully-automatic means that the entire printing process is completed by machinery.

▼8. How is screen printing classified?

Screen printing is not only suitable for general paper printing, but also has a very wide range of adaptability. For example: ceramics, glass, printed circuit boards, etc. Depending on the texture of the substrate, printing will be different. Although there is an inseparable internal connection between each series, each has its own particularity due to the different textures of the substrate (that is, different chemical and physical properties). Therefore, people usually divide them into several categories according to different substrates: paper printing, plastic printing, ceramic printing, glass printing, circuit board printing, metal printing, textile printing and so on. In this way, each relatively independent printing system is formed.

▼9. What are the main applications of screen printing?

The application range of screen printing is very wide. Except for water and air (including other liquids and gases), any object can be used as a printing substrate. Someone once said this when evaluating screen printing: If you want to find the ideal printing method on earth to achieve the purpose of printing, it is probably the screen printing method.

Specifically, screen printing is mainly used in the following areas:

①Paper printing

Art printing - advertisements, illustrated magazines, calendars, lanterns paper etc.

Trademark printing

Transfer printing

Packaging printing

Building materials printing - wallpaper, etc.

②Plastic printing

Plastic film-vinyl toys, school bags, plastic bags, etc.

Plastic dials - fake metal composite materials and various dials.

Production of parts - instrument parts.

③Wood product printing

Crafts - lacquerware, wooden crafts, toys.

Processing of semi-finished products - sporting goods, wooden boards, ceilings, road signs, signs, fake metal levers, billboards, etc.

④Metal product printing

Metal cylinders, metal utensils, and metal products.

⑤Printing of glass and ceramic products

Glass - mirrors, glass plates, cups, bottles, etc.

Ceramics - utensils, handicrafts.

⑥Signs

Text instruction boards, dials, and formed items.

⑦Circuit board printing

Printed circuit boards, civil or industrial substrates, thick film integrated circuit boards.

⑧Printing and dyeing

Printing and dyeing--flags, cloth, towels, handkerchiefs, shirts, vests, knitwear, etc. '

Other printing - pockets, shoes, bib numbers and various bags, backpacks, handbags, schoolbags, etc.

⑨Leather product printing

▼10. What is the main process of screen printing? Is the process flow needle?

The main process of screen printing is: making original manuscript, making screen printing plate, printing, ink drying, etc.

▼11. What is a tensiometer?

A tensiometer is an instrument that measures the mutual traction between the interior of the wire mesh and the fixed wire mesh contact body when it is subjected to tension. There are two types of tensiometers: mechanical and electronic. The unit for measuring tension is expressed in Newton/centimeter. Tension can also be expressed as a relative value. Centimeter tensiometer is a type of tension that uses relative values ??to express tension. It is calculated by the value (mm) of the depth to which the wire mesh sinks due to the weight of the tensiometer. The tension value can be obtained directly from the indicator panel or indirectly from the control panel. get. There are two types of tensiometers: manual operation and mechanical operation. The tensiometer is an important testing instrument for testing the quality of screen printing plates. In order to ensure that the tension required for plate making is obtained, a tensiometer must be used to measure during or after stretching the web.

▼12. What is a mesh ruler? What is its purpose?

The mesh ruler is also called the latitude and longitude density meter. Mainly used to measure the mesh size of various wire meshes. There are two types of mesh rulers: glass plate type and plastic sheet type. The measurement method is: when measuring, first make the screen in a transparent state or place it on the viewing table, place the mesh ruler on the screen, and then move the mesh ruler slowly on the screen to make the mesh The vertical lines on the ruler are parallel to the warp or weft lines of the screen. At this time, due to the overlapping effect of the warp and weft lines of the screen and the vertical lines on the mesh ruler, a prismatic pattern is formed on the mesh ruler. The transverse diagonals of the pattern point to The corresponding scale number on the mesh ruler is the mesh number (inches or centimeters) of the screen being measured.

The mesh ruler is a common tool for measuring the mesh number of the screen. Generally, to maintain the accuracy of the measuring instrument and the accuracy of the measurement data, it is necessary to keep the mesh ruler clean and prevent scratches on the mesh ruler. If there are any scratches or bruises, wipe the instrument clean after use and keep it properly.

▼13. What is a density meter? What is the use of a density meter?

The density meter is a commonly used original measuring instrument in printing factories. It is a photoelectric measuring instrument for measuring the gray value of black and white originals and measuring the continuous tone or dot value. There are two types of density meters: transmission density meters and reflection density meters. The transmission density meter is suitable for measuring transparent originals, and the reflection density meter is suitable for measuring field originals. The measuring range of the density meter is 0-2.5, the larger the number, the higher the blackness. The basic principle of measurement is to measure the degree of blackening of photosensitive materials after exposure and development, that is, blackness. During plate making, the silver bromide on the photosensitive material is exposed to light and is reduced to metallic silver after development, forming a certain degree of light blocking. The greater the blackness, the higher the density; the smaller the blackness, the lower the density. A measuring meter with a filter can also measure the color density of color originals. Its measurement principle is similar to the above basic principle.

▼14． What is a colorimeter? What is its purpose?

Colorimeter is also called colorimeter. It is an instrument that measures the color characteristics of materials. The main purpose of the colorimeter is to measure and analyze the color, hue, and color value of the material being measured. If the colorimeter is connected to a computer, the color analysis and processing capabilities can be improved, and the user can retrieve various data from the computer's color storage library for color matching as needed.

▼15． What is a hardness tester? What is its purpose?

A hardness tester is an instrument for measuring the hardness of an object. It can be divided into two types: simple hardness testers and complex hardness testers according to the degree of complexity. Hardness testers are widely used and are commonly used in the rubber industry. In the screen printing process, hardness testers are mainly used to detect the hardness of scraper materials.

Edit this section Aluminum sign classification 1. Silk screen aluminum oxidation color sign Aluminum flat anodized sign is also a type of sign, and it is widely used. It has the characteristics of high brightness, high hardness and good wear resistance. The traditional production process is roughly as follows: mechanical polishing, chemical polishing, oxidation; indirect plate making to make screen printing plates, thick zinc-barium white paint and alkyd varnish for protective printing. In this way, whether it is screen making or dyeing, there are many processes and use of Disadvantages include large material size, low print durability, and high cost. Today, we adopt the latest technology and use non-toxic nitrogen-type photosensitive glue to directly make plates, which can meet the requirements of rapid plate making, high resolution, high print durability and low material consumption. It can also combine the processes of printing, dyeing and deprinting materials into one, using self-made water-based dyeing materials, direct dyeing and continuous color registration. This can greatly simplify the entire process and operating procedures, giving flat oxidation dyeing signs a new process. 2. High-gloss three-dimensional embossed aluminum signage With the continuous improvement of production technology, people have higher and higher requirements for material and spiritual life. People not only have higher and higher requirements for product functions, but also have higher and higher requirements for product appearance and decoration. Especially with the continuous expansion of the foreign trade market, in order to improve the market competitiveness of products, high-gloss three-dimensional relief signs for high-end products have been widely used. 3. Silk screen electroplating plaques are one of the main products of the sign factory and are mainly used for company signs. Plaque materials are mainly made of metal, which requires solemnity, prominent image, and strong decorative properties. Traditional metal plaques are mainly square plaques with brass ground, corroded characters, and black paint. However, as people's aesthetic views continue to change and the commodity economy gradually develops, there are also new requirements for the quality and appearance of plaques. The introduction of screen printing processing technology in the sign industry not only promotes the development of screen printing technology, but also provides technical support for the development of new products in the sign industry. Silk screen electroplating plaque is the product of combining sign electroplating and silk screen printing processes. The basic method of silk screen electroplating plaque is: first use silk screen technology to produce plain text on the copper plate, use an ink layer to protect the non-graphic part, then conduct copper, nickel, and chromium electroplating on the graphic part, and finally carry out mechanical shaping to protect the processing. become. 4. How to screen-print conical scales: First use a screen printing screen to print the graphics and text on the transfer rubber, then install the conical parts on the fixture, and then roll them over the transfer rubber. Graphics and text can be printed on the surface of conical parts. 5. Imitation porcelain oxidation signs: Imitation porcelain anodized signs have a enamel-like surface and soft color. They have the advantages of good resistance, high hardness, good wear resistance, and thermal insulation. They are a good decoration for instruments and meters. During the production process, polluted waste gas will be emitted, so the equipment must be equipped with exhaust ventilation equipment to avoid poisoning. The surface treatment of imitation porcelain signs is roughly the same as that of silk screen sandblasting and oxidized inlaid paint signs, except that it does not require chemical polishing and can be directly oxidized. The process of imitation porcelain oxidation dyeing signage is the same as that of silk screen printing aluminum oxidation color signage. 6. Silk-printed aluminum oxidation signs. After the aluminum oxidation signs and panels are oxidized, an oxide film will be attached to the surface, making the surface hard and smooth. Ordinary screen printing ink has poor adhesion, which is the most important problem. To solve this problem, we must first solve the screen printing ink and operation problems. Aluminum oxide screen printing ink must be used, which is the key to the success of screen printing aluminum oxide signs. The difference between this type of ink and ordinary ink is that it will adhere firmly to the surface of the aluminum plate and has good light resistance. This is the most ideal ink for screen printing aluminized signs. 7. Silk-screen corrosion signs Corrosion signs are a type of traditional signs. Common signs include sandblasting, oxidation and paint-filled signs, such as: vehicle and ship license plates, equipment numbers, various machine tools and electrical appliances nameplates; copper-plated signs for mechanical and electrical products with harsh operating environments. ; Porcelain oxide paint signs and high-gloss signs used for surface decoration of instruments and electronic instruments. The graphics and text on such signs used to be realized through photochemical action using liquid photosensitive adhesive. This method has the disadvantages of numerous manufacturing processes, low production efficiency, and high labor intensity. 2. Silk screen processing technology is used to print graphics and text, which greatly improves production efficiency and saves a lot of raw materials. 8. Silk screen embossed and concave colored aluminum signs are characterized by painting the recesses, which have good wear resistance and a three-dimensional effect. They are generally used for mechanical nameplates and company plaques. The traditional production method is to manually paint the corroded recesses and then trim them by hand. This method of removing residual paint on the edges is not only time-consuming and inefficient, but also requires the operator to be very skilled. In addition, the produced signs become unclear and the quality is poor. Stablize. It is only suitable for making some simple signs with small batches, few colors and low quality requirements. If you use screen printing technology, there will be no such problems.

9. Silk-screen sandblasting and oxidized paint-embedded aluminum signs. Silk-screen sandblasting and oxidized paint-embedded aluminum signs are a traditional signmaking process. This type of product has a silvery white appearance, high surface hardness, and good wear resistance. 10. Silk-printed water-white alumina signage Water-white alumina signage is a new type of matte surface sign that has appeared in my country in recent years. This type of sign has a milky white appearance and a smooth surface. It is resistant to heat and humidity, salt spray, and mold. It also has strong light resistance, abrasion resistance, and organic solvent resistance. It is suitable for machine tools and working environments that require frequent wiping. The whole machine under relatively harsh conditions. The most important thing is that the arbitrary water-white alumina signs have fewer and higher process steps, and basically no three wastes are produced.