Detailed step-by-step analysis of screen printing screen production—\x0d\The quality of the screen during the printing process is directly related to the quality of the printed products. Therefore, the screen production process deserves in-depth study and discussion by industry insiders. . \x0d\\x0d\ 1. Detailed explanation of the screen production process \x0d\\x0d\ Generally speaking, the production process of screen production is also different due to the different photosensitive materials used, but no matter which process is adopted, screen production The following steps are indispensable in the process: screen and screen frame selection, screen stretching, screen washing, photosensitive material coating, exposure, development, and drying. \x0d\\x0d\Let’s learn more about the operation methods and precautions of each process. \x0d\\x0d\1. Selection of wire mesh\x0d\\x0d\There are many types of wire mesh on the market, such as silk mesh, nylon mesh, polyester mesh, metal mesh, etc. Generally speaking, they are based on cost and application In terms of safety, nylon mesh is the most commonly used type of mesh on the market. \x0d\\x0d\Introduction to the characteristics of nylon wire mesh\x0d\\x0d\Nylon wire mesh has a smooth surface, good ink permeability, softness, high elasticity, strong adaptability, good tensile strength, elasticity and friction resistance. Due to its high nodule fastness, long service life, acid resistance, chemical resistance and excellent organic solvent resistance, it is favored by fine printing and widely used in fine line painting patterns and dot printing. \x0d\\x0d\Precautions for use:\x0d\\x0d\In addition to the above advantages, nylon mesh also has some disadvantages, such as large elongation, low heat resistance, etc. Therefore, nylon mesh should be used when using it. Pay attention to the following points:\x0d\\x0d\·Due to the high elongation of nylon screen, it is required to use a strong screen frame and stretcher during printing;\x0d\\x0d\·For the durability of nylon screen It has the disadvantage of low heat resistance, so do not use hot melt method to fix the screen during printing;\x0d\\x0d\·Ultraviolet rays will also have some impact on nylon screen, so you should keep nylon screen or its corresponding screen. Be careful to avoid light. \x0d\\x0d\2. Selection of screen frames\x0d\\x0d\According to material, there are generally six types of screen frames: wooden frame, aluminum frame, iron frame, plastic frame, stainless steel frame, and copper frame. The commonly used ones are wooden frames. , aluminum frame, iron frame, etc. \x0d\\x0d\·Wooden frame: relatively cheap, easy to make, and can be stretched manually or mechanically. However, its shortcomings are low charging and easy deformation. It is only suitable for printing low-precision products. It is not suitable for fast and high-precision screen printing. In addition, the screen pulled out of the wooden frame is loose and has poor recyclability. \x0d\\x0d\·Iron frame: Compared with the wooden frame, it is dimensionally stable, sturdy and durable, but it is heavy, easy to rust, and inconvenient to use, and only mechanical stretch nets can be used. \x0d\\x0d\·Aluminum frame: Although it is only suitable for mechanical stretching, it has the characteristics of small deformation, light volume, not easy to rust, and easy to move. Therefore, aluminum frame is the most commonly used type in printing plate making. Net frame. \x0d\\x0d\ 2. Stretching the net\x0d\\x0d\In general plate making, the methods of drawing the net can be divided into three types: manual, mechanical and pneumatic. For example, silk screen processing factories do not have high requirements for precision, and generally adopt The first two methods are sufficient; if the requirements are higher, the last pneumatic stretching machine can be used. The pneumatic stretching machine is suitable for high-precision screen drawing. It is characterized by uniform pulling force, easy use, and can achieve different screen tensions according to different needs. It is especially suitable for drawing screen printing plates for high-precision printing. \x0d\\x0d\3. Screen washing\x0d\\x0d\When printing and plate making, special chemicals are generally used for screen washing (such as defilming water, diluent, detergent, etc.), but this method is time-consuming. Therefore, this method is a little troublesome for those processing plants that are concerned about timeliness. Here I would like to share with you an effective method: use a washing powder with strong detergency, such as Tide, to wet the stencil, and then polish it with cotton cloth. , this method not only removes stains quickly, but also facilitates the adhesion of photosensitive adhesive, which can be said to kill two birds with one stone. (Note: For the above method, you need to polish both sides when polishing. When polishing the front, you need to use lighter force to prevent the mesh from falling off.) After washing the net, put the net in the dryer to dry and set aside. \x0d\\x0d\ IV. Coating\x0d\\x0d\1. Selection of photosensitive materials\x0d\\x0d\ There are two types of photosensitive materials currently used on the market. One is photosensitive glue. Its advantages are The process is simple, economical and practical, and the exposure speed is fast. The screen is durable, easy to remove the film, and has excellent solvent resistance.

The other is photosensitive film. This film is a pre-sensitized photosensitive material that is affixed to the screen before exposure. It is hydrophilic, has strong resolution, good line sharpness, is sturdy and durable, and has excellent performance. For photosensitive adhesive, it is commonly known as "water film" because of its hydrophilicity. \x0d\\x0d\ Generally speaking, printing requirements for photosensitive materials are: the plate film formed by the photosensitive material should be suitable for the performance requirements of different types of inks, and should have considerable printing durability and be able to withstand a considerable number of squeegees. It has good scraping pressure and good bonding force with the screen. It will not cause release failure during printing and is easy to peel off, which is conducive to the recycling of screen plates. \x0d\\x0d\2. Items required for coating\x0d\\x0d\: photosensitive glue, sizing device (squeegee), and mesh platform. \x0d\\x0d\ The photosensitive slurry on the market requires you to adjust it yourself. You can use hot water to moisten the photosensitive powder first, then pour it into the photosensitive slurry and mix thoroughly. It can be used after a few hours. Small factories can have plate-making workers complete the sizing, while large factories have automatic sizing machines with very uniform thickness. The operation steps are:\x0d\\x0d\·Place the dried ready-to-use mesh on the glue coating table, and place the screen Steady, pour the photosensitive adhesive into the scraper. (Note: Appropriate amount)\x0d\\x0d\·Use a scraper to evenly apply photosensitive adhesive on the screen. Apply the printing surface first (the convex surface of the screen), and then the ink surface (the concave surface of the screen). Generally, apply on each side. Cloth three times. \x0d\\x0d\·Then dry the net, this process is the first time. (Note: Screen printing of lines and characters requires secondary coating)\x0d\\x0d\·If a thick screen is required, it can be applied in multiple times, that is, after the first application of glue, immediately put in 30-40 Dry it in an oven at ℃, take out the screen and apply glue again. Determine the number of times of glue application according to the required thickness. Note that generally the printing surface (convex surface) is coated 2-3 times more than the ink surface (concave surface). This operation is Second coat. (Note: This coating is only done on the contact surface of the screen)\x0d\\x0d\·Use a hair dryer or oven to dry. Do not dry it dry or not dry, so as not to affect the quality of plate making. (Note: The photosensitive glue is peeled off) \x0d\\x0d\ Note: The glue coating process is very important. The quality of the screen depends entirely on the glue coating. The thickness of the screen is required to be uniform and three-dimensional. \x0d\\x0d\3. Drying\x0d\\x0d\After the screen printing photosensitive adhesive is applied, let it stand for 1-2 minutes, then put the screen into an oven at about 40℃ to dry. After drying, take it out and put it away. Ready in dark frame. \x0d\\x0d\Note: The screen must be dried, otherwise the solidity of the screen will be affected. \x0d\\x0d\ 5. Exposure \x0d\\x0d\ Attach the film surface of the negative film to the printing surface (convex surface) of the screen, and then place it in a vacuum exposure machine for exposure. The exposure time depends on the thickness of the photosensitive adhesive, the energy of the exposure lamp and the requirements of the screen (general lines, solder masks, characters, and screen require different exposure times). Generally, it is measured with the help of an exposure slide rule before use. Exposure time, and then fix the exposure time of the produced screen. \x0d\\x0d\Steps: \x0d\\x0d\·First, use a magnifying glass to align the film with the longitude and latitude of the silk screen. The lines should be parallel and perpendicular to the silk screen wires. (Note: Especially lines and characters)\x0d\\x0d\·Put the calibrated net into the exposure machine, adjust the time, and after the vacuum is reached, turn on the exposure machine switch. \x0d\\x0d\Note: If the exposure time is too short, the photosensitive adhesive will easily fall off, the lines will become thicker, the solder mask points will not be strong, the characters and symbols will not be strong, etc.; if the exposure time is too long, it will cause incomplete development or Quality accidents such as thinning of lines occur. Therefore, it is particularly recommended that accurate exposure time comes from scientific practice. Before exposure during production, you must use an exposure slide rule to measure the exposure time, and then fix the exposure time. Do not rely on experience or work blindly. \x0d\\x0d\ 6. Development \x0d\\x0d\ Remove the screen from the exposure machine, remove the film, first wet both sides of the screen with gentle, pressure-free cold water (warm and cold water 20-30℃), keep it wet for about 30-60 Seconds later, rinse thoroughly with a high-pressure water gun until the image appears, then use an absorbent cloth to absorb excess water around it, and then put the screen into an oven at 30-40°C to dry.

\x0d\\x0d\Steps:\x0d\\x0d\·Wet both sides of the exposed screen with water for about 1 minute, then rinse the screen with high-pressure water until it is completely clear;\x0d\\x0d\·In the light Check next to see if it is completely clear and whether the plate making is successful. If it is not good, redo it;\x0d\\x0d\·After drying the wet screen, place it under a light box and use sealing slurry to repair defects such as trachoma and burrs. \x0d\\x0d\7. Check the screen ready for use\x0d\\x0d\ After the screen is dried, carefully check whether the screen produced meets the production and processing requirements. If it meets the standards, seal the screen immediately so that the production personnel can wait for it. Use it; if it does not meet the requirements, repair or remake it immediately. Principle:\x0d\Screen printing consists of five major elements, namely screen printing plate, squeegee, ink, printing table and substrate. The basic principle of screen printing 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 onto one end of the screen printing plate, use a squeegee to apply a certain amount of pressure on the ink part of the screen printing plate, and at the same time move it toward the other end of the screen printing plate. 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 schedule\x0d\\x0d\Characteristics and process arrangements of screen printing\x0d\\x0d\1. Screen printing process arrangements\x0d\\x0d\Screen printing is a direct printing method, and there are three process arrangements : ① Cardboard → Screen printing → Post-press processing, that is, screen printing is first performed on corrugated cardboard or other cardboard, and then made into cartons and carton products as needed; ② Carton → Screen printing, that is, directly on the already produced Screen printing on corrugated cartons or other cartons and cartons; ③ Secondary processing, that is, first screen printing on the cardboard, and then make corrugated cardboard as needed, and then make cartons and carton products. 2. Characteristics of screen printing ① Wide adaptability: the screen printing format can be large or small; ② Thick ink color: Among all printing processes, screen printing has the thickest ink layer, high saturation, and better spot color printing effect; ③ Low cost: screen printing is easy to make plates and the printing process is simple; ④ The quality of printed matter is stable; ⑤ Low production efficiency: the screen printing speed is slow and not suitable for online production; ⑥ The image accuracy is low: the screen printing resolution is not high, conventional screening lines Count from 24 lines/cm to 32 lines/cm. \x0d\\x0d\3. Scope of application of screen printing \x0d\\x0d\ Screen printing is suitable for small batch production, packaging products with high printing appearance requirements, unlimited cardboard thickness, and no loss of strength. \x0d\\x0d\Screen printing process\x0d\\x0d\1. Screen version production (1) Screen selection ① Nylon screen: Nylon screen has high strength, high wear resistance and high alkali resistance , slightly poor acid resistance, good ink permeability, small wire diameter, good elasticity, and bright imprint; ②Polyester screen: Polyester screen has good stability, high strength, corrosion resistance, performance is better than nylon screen, and the tension of the screen is High, suitable for high-precision printing; ③ Stainless steel screen: Stainless steel screen has high strength, good stability, small wire diameter, high mesh, good resistance, long life, poor elasticity, easy to break when impacted, suitable for precision printing. Not suitable for curved surface printing; ④ Nickel-plated polyester screen: Nickel-plated polyester screen combines the advantages of polyester screen and stainless steel screen, with wide applicability, moderate price and poor corrosion resistance. \x0d\\x0d\ Wire mesh includes plain weave, twill weave, semi-twist weave, and full twist weave. White screens can easily cause diffuse reflection when exposed, while golden, red, and amber colors absorb ultraviolet rays and prevent halos. The mesh numbers of wire mesh include 30 mesh/cm, 40 mesh/cm, 60 mesh/cm, 80 mesh/cm, 120 mesh/cm, 140 mesh/cm and 160 mesh/cm. Generally, the mesh The number is large and the diameter of the mesh is small. Fine wire mesh has high resolution; thick wire mesh has low resolution.

When printing on curved surfaces, use a screen with high elasticity, such as nylon mesh; when printing on absorbent substrates, use a screen with a large mesh area; when printing on smooth surfaces, use a screen with high elasticity and high tension; when printing on rough surfaces, use a screen with high elasticity and high tension. When printing, use a low-mesh screen; when printing high-precision prints, use a low-elongation, high-tension screen; when printing signs, textiles, and knitwear, use a 28 mesh/cm ~ 78 mesh/cm screen; For paper, metal, glass, leather, and plastic, use 40 mesh/cm ~ 140 mesh/cm screen. \x0d\\x0d\(2) Stretching net\x0d\\x0d\Silk screen version of the screen frame includes wooden frame, metal frame, plastic frame, combination frame, etc. When stretching the net, clean the screen frame first. The net can be stretched manually, mechanically or pneumatically. After the net is stretched, it is bonded and trimmed. Stretching the mesh requires that the mesh tension be appropriate, uniform and stable, the wire direction should be consistent, avoid diagonal pulling, and the warp and weft wires should be parallel to each other. \x0d\\x0d\(3) Plate making\x0d\\x0d\ ① Direct method: screen cleaning → applying photosensitive glue → printing → developing → revising. This method of gluing is time-consuming, the film thickness is adjustable, the bonding is firm, and it is resistant to printing, and the graphics and text are prone to jagged edges. ②Indirect method: photosensitive film → exposure to plate → development → film film → peeling off film base → plate modification. This method is complex to operate, has smooth lines, weak film, low print durability, and unchanged film thickness. ③Mixing method: screen cleaning → film film → printing → development → revision. This method is easy to operate, has a fixed thickness, smoother lines and is stronger. \x0d\\x0d\(4) Silk screen direct plate making\x0d\\x0d\Silk screen direct plate making is referred to as CTS (ComputerToScreen). ① Laser ablation direct plate making: first apply screen photosensitive glue on the metal screen, use laser to burn through the photosensitive layer, the mesh of the graphic part is transparent, and the prepress system computer controls the ablation place. This method can only be used for metal net. ② Laser exposure direct plate making: first apply photosensitive glue on the screen, and the pre-press system computer controls the laser to image on the screen to make a screen plate. This plate making method uses special photosensitive glue, the ultraviolet light wave range is narrow, and the price of the laser exposure system is high. ③Inkjet imaging system: First apply photosensitive glue on the screen, and the pre-press system computer controls the inkjet system to spray the light-blocking ink onto the photosensitive layer of the graphic part, and then fully expose it to ultraviolet light. The graphic and text parts are not exposed to light, so rinse off the photosensitive glue; the blank parts are photohardened. This method can use ordinary photosensitive glue without losing image details. \x0d\\x0d\2. Screen printing machine\x0d\\x0d\ Screen printing machines include manual screen printing machines, semi-automatic screen printing machines, and fully automatic screen printing machines. There are also screen printing machines such as book lift type, table lifting type, sliding table type, roller table type, curved table type, curved surface type, drum screen type, double drum type, etc. You can choose according to your needs. \x0d\\x0d\3. Special screen printing method\x0d\\x0d\ ①UV imitation metal etching printing UV (ultraviolet) imitation metal etching printing is to print a layer of uneven semi-finished semi-finished metal on a substrate with metallic mirror gloss. The transparent ink is then cured by UV light to produce an effect similar to that of a bright metal surface that has been etched or frosted. The printing is elegant and luxurious, and is used for high-end and exquisite packaging. This printing method uses UV curing imitation metal etching ink, the substrate is gold cardboard, silver cardboard or composite materials, and a 70 mesh/cm to 100 mesh/cm screen is used. ②UV wrinkle pattern ink printing UV wrinkle pattern ink printing is to use UV wrinkle ink to print on the surface of the substrate and then cure it with ultraviolet light to form a special wrinkle pattern decorative effect. This printing method uses a 40 mesh/cm ~ 60 mesh/cm screen, and the ink film thickness is 20μ ~ 30μ. The larger the thickness, the better the effect. ③Ice flower effect printing Ice flower effect printing is to print ice flower ink on the surface of a substrate with metallic luster using silk screen printing. After UV curing, it will appear like ice flowers. The substrate for this printing method is gold and silver cardboard, and a screen of 60 mesh/cm to 100 mesh/cm is used. ④Foam printing Foam printing uses microsphere foaming ink and uses a screen to print on paper or other substrates. The graphics and text are raised. It is widely used in the printing of book binding, Braille, maps, packaging and decoration. This printing method uses a 30 mesh/cm to 50 mesh/cm screen. The screen can also be used for scented ink screen printing, pearlescent ink screen printing, liquid crystal ink screen printing, phosphorescent ink screen printing, fluorescent ink screen printing, crystal gloss screen printing, etc.

\x0d\\x0d\High-speed rotary screen printing production line\x0d\\x0d\ Due to the low printing speed of flat screen printing, slow ink curing speed, difficult to control printing quality, and high consumption of printing materials, it cannot meet the needs of cigarette cartons scale and mass production needs. Using a high-speed rotary screen printing production line, the printing speed is fast, the productivity is high, the print quality is stable, and the consumption is low. It changes the traditional flat screen printing, manual paper supply, and ink supply methods, and is suitable for high-speed automatic, large-scale batch production of exquisite products. Folding carton. \x0d\\x0d\Web rotary screen printing uses a nickel metal round screen printing plate, a built-in doctor blade and an automatic ink supply system. The doctor blade transfers the printing ink from the round screen plate to the impression cylinder. The supporting substrate surface. The entire printing process, from paper feeding, ink supply, color registration, UV drying, etc., is fully automatically controlled by the computer. \x0d\\x0d\ The circular screen printing plate is suitable for large-format rotary printing, the maximum speed can reach 125m/min, and the screen can be reused. Therefore, web rotary screen printing can not only meet the requirements for printing special effects such as frosting and ice flowers, but also can online hot stamp holographic anti-counterfeiting logos, concave and convex tooth marks, and die-cutting indentations, making it easy to achieve high-speed automatic printing. Number of carton tickets: 1