In the production process of signage, it plays a decisive role in the process technology of screen printing plates and substrates, and the selection of printing points and screen printing inks.
First, screen printing system board
1, paint film engraving method:
It is a kind of manual plate making method and it is relatively simple. It can print monochrome and non-exquisite monochrome designs and text.
(1) Sprayed stenciled film paper: Stick the tracing paper with a paste on a flat wood plate. Use a screed to adjust the rubber water to 1 part (volume ratio) and 1 part of the gasoline. Apply evenly on the paper. , Dry after spraying soft varnish 3-5 times, after each spraying, in the oven with 40 degrees to 50 degrees drying, the film thickness is sprayed to 5 ~ 6 mm is appropriate, the film should be bright, uniform, no bubbles No blemishes.
(2) Engraving pattern: Put the paint film on the figure, and then use a carving knife, a circle knife and a ruler to sculpt according to the figure, gently remove the paint film.
(3) Reposting: After engraving the graphics, it can be reposted on the screen frame that was made in advance. The method is to press the well-formed film under the mesh frame, and gently rub it with a little dilute material on the cotton until the paint film sticks to the mesh. After drying for a few minutes, remove the tracing paper. If the paper is not completely removed, wipe it with cotton. The blank part is coated with nitrocellulose and the mesh of the screen is plugged. Allow to print after drying.
2, carbon paper printing method:
It is also a relatively simple manual plate making method.
(1) Photosensitive paper: Photosensitive paper is a kind of mixture of carbon paper made of oxygen and made of thick paper. The size of the pattern is cut and ready for use.
(2) Sensitization: soak in a solution of 500 milliliters and 20 grams of ammonium dichromate for 3-5 minutes, remove the carbon paper, and drain the water.
(3) Exposure: Put the carbon paper flat on the cleaned glass with the film facing up, covering the positive polyester film base plate on the top and exposing with a printing machine. The exposure time is 8-12 minutes.
(4) Development: Exposure for 40 minutes in 40 to 50 degrees warm water, so that the film and the positive plate are naturally detached from the zinc oxide base paper, and carefully developed with warm water until the text is clear.
(5) Reposting: Put the prepared version under the mesh frame of the wire mesh that has been stretched beforehand, cover several layers of newspapers above the wire mesh, and press the glass plate with a weight of 1-2 kg/cm2. When the film and the screen stick securely, remove heavy objects and newspapers, use the electric oven to dry the film, and then remove the original paper, the film pattern is transferred to the screen. Carefully check the graphics for defects. After qualifying, apply a layer of nitro-chrome paint on the screen surrounding the pattern to protect the screen printing plate on the plate table for printing. The scope of application of this plate making method is the same as that of the film engraving method.
3, photosensitive plate method: silk screen printing plate used by the higher accuracy requirements, generally use advanced direct, indirect, straight between the three photosensitive plate method.
A, direct plate method:
(1) Aluminium frame is used for post frame, no stretching net is required for maneuverability stretch net, air pressure is 5-6 kg/cm2, acetal glue is used to stick net, tension degree of tension is measured with tension, tension is 5-7 kg, sinks The size should be less than 2mm.
(2) Wash the wire mesh: Use detergent, detergent, ethanol, etc. as cleansing agent, wash both sides of the wire mesh, rinse with clean water, and dry it after hot air drying. The purpose is to make the net bond better with the photo resist.
(3) Scraping bucket (coating bucket, applicator): The scraper coated with sensitized rubber can be made of stainless steel, and scrapers can also be made of organic glass plates. Its length is generally slightly smaller than the inner diameter of the screen frame (several scrapers of different lengths are paired together). The edge of the scraper must be thin and not edged, smooth and straight, and does not allow defects such as bumps, burrs, and scars, affecting the quality of the plate. When applying the screen-sensitive adhesive, it is necessary to dry it once every three times for three times, until the film reaches the required thickness, and then perform exposure.
(4) The temperature of the drying oven, ideally with a temperature-controlled drying oven. The drying temperature of the emulsion is generally controlled at about 40 degrees. Too long baking time or too high temperature will affect the quality of the photosensitive layer.
(5) Security lighting: The lighting source of the studio generally uses orange, yellow or red light as the security light, but from the visual point of view, the orange light source is more comfortable. Its brightness is suitable to clearly see everything.
(6) Inspection of the bottom plate: Before the printing plate, the bottom plate must be inspected carefully, including whether the dust on the plate surface, the darkness of the bottom plate, the line breakage, the sand hole defect, etc., and the positive and negative of the image text meet the requirements.
B. Indirect method:
(1) Prepare the frame and photosensitive film: Clean the frame (the nylon thread is 220-260 mesh) with a 10% aqueous sodium phosphate solution to remove oil stains.
The line network photosensitive film is a kind of photosensitive adhesive mainly composed of polyenol glue. The film is coated with gelatin as the main sensitizer on the base of 0.12-0.06 mm transparent plastic film. The size of the pattern is used before being used. Each side is wide. Take out 20 mm and wipe the dirt on the membrane with a cloth.
(2) Exposure: The film and the bottom plate are pressed tightly in the printing machine and exposed with a carbon or xenon lamp. The distance between the frame and the light source is 50-60 cm and the exposure time is 2-6 minutes.
(3) Development: After exposure, the film is placed on a flat plate, and the omentum is soaked in warm water for 1-2 minutes. The water is sprayed on the sprinkler. The non-photosensitive part (graphic part) is printed with water, and the resulting film is developed. Until the graphics are clear.
(4) affixed to the film: the film surface of the film is exposed on the screen, the back of the film with a rubber board or other straight, gently scraping, so that the film and the net contact firmly, immediately placed in the oven, at the temperature Baking for 8-12 minutes under the condition of 55±2 degrees, after drying, the mesh frame is fixed on the plate for test printing.
(6) Film removal method: In the process of exposure and development, when the unsatisfied version is found, immediately use warm water to brush off the film and re-create it. If the plate is dry or it is removed after production for a period of time, use one part of industrial sodium hypochlorite and water and soak for 10-20 minutes. Or 5% sodium hydroxide aqueous solution heat treatment screen, you can remove the film.
C, straight between the plate method:
Straight line method is a mixed plate method of direct method and indirect method. The difference between it and indirect method is that indirect method is first applied to the film on the film and then transferred to the screen, and the direct method is to first film film. Transfer to the screen and make an image after exposure.
Second, the pre-processing of printing materials
The label printing materials mainly include aluminum, copper, stainless steel and aluminum. The amount of organic glass is the most. There are also plastic, polyester, paper and so on.
Aluminium signage is a widely used type of signage, with characteristics of beauty, brightness, high hardness, good wear resistance, wide application, and large amount. For machinery, electronics, instruments, meters, household appliances, daily hardware, watches, daily cosmetics packaging.
There are various methods for the pretreatment of the aluminum substrate. According to the application, there are mainly degreasing, sandblasting, wire drawing, polishing, and oxygen grease.
1. Degreasing: In order to make the surface of the aluminum substrate have certain ink affinity, it is necessary to remove the oil layer and oil on the surface, and wipe it with cotton yarn and gasoline. Chemical degreasing can also be carried out with an alkaline solution, such as sodium sulfate 30-50 g/L, sodium phosphate 40-60 g/L, sodium silicate 10-15 g/L, dipping 2-5 at a temperature of 60-70C. Degreasing in minutes.
2, sandblasting: sandblasting is to improve the adhesion of ink and metal materials, usually using a special sandblasting machine spray treatment, if the 0.5-1 mm thick aluminum plate, sandblasting sand with a diameter of 0.05-0.15 mm, also Available river sand, sieved and used.
3, drawing: also known as skein processing, is to use the method of mechanical friction on the surface of the aluminum plate to produce a fine linear line. It is a relatively new surface decorative treatment process that can overcome defects such as scratches on aluminum surfaces. Improve the use of materials. There are two types of wire drawing, such as stainless steel wire brush with a diameter of 0.1 mm or a brush with a scouring pad, and nylon belts.
4, polishing: to overcome the surface defects of aluminum-based materials, improve the surface finish. Polishing is divided into mechanical polishing and chemical polishing. Mechanical polishing uses a cloth wheel polisher, and the chemical polishing is performed in an acidic solution such as sulfuric acid 15%, nitric acid 10%, temperature 90-100 degrees, and time 2-3 minutes.
5. Oxidation: The surface of the polished aluminum plate has residual polishing soap, which is wiped off with a veil of yam and then chemically deoiled. Then it is immersed in a nitric acid solution (1:1 ratio of nitric acid and water) and removed after 10 minutes. Then placed in an oxidation tank for electrochemical oxidation. Oxidized liquid formula: nitric acid 160-200 g/ml, temperature 10-20 degrees, time 30 minutes.
The well-oxidized aluminum plate is fully washed and air-dried, and a layer of uniform oxide layer, ie, an oxide film, is formed on the surface, and contamination of the contaminants should be avoided. Good oxidation of aluminum is best to immediately print [encyclopedia microblogging], if not immediately printed, use soft paper septa wrapped or directly on the air frame, storage time can not exceed one week.
The oxide layer on the surface of the aluminum plate can adsorb dyes, moisture, and other salts, so the surface is not touched by hand or with oily material during screen printing. When the ink is printed on the oxide layer, the ink penetrates into the pores. The warming of the next step is to accelerate the ink into the pores until all the ink-covered surface pores have been filled.
The ink printed on the surface rarely spreads or does not spread, ensuring the accuracy and clarity of the text and the pattern.
6, closed: Its role is to firmly seal the ink in the pores, never overflow or spread. For areas that are not filled with ink, the function of the seal is to fill the gaps of the oxide film and make it impervious to water and enhance the corrosion resistance of the surface. Nickel sulfate solution is generally used for sealing. Formula: 10-12 ml of nickel vanadate, temperature 80-90 degrees, 10-15 minutes. After sealing the hole, touch the surface with hand or other oily thing and wash it off with a general cleaning agent.
Third, silk screen printing ink (paint)
In today's metal plate or non-metal screen printing, more printing inks can be used, but it is not easy to select suitable inks (coatings). There are the following inks commonly used for silk screen printing:
1, baking enamel:
It is a single-liquid formulation that cross-links when heated and has good storage properties. Can be stored for 6 months to a year. Has a good finish, wear resistance, chemical resistance and weatherability, and thus the most commonly used. Alkyd, acrylic and polyester have these properties. Epoxy resins tend to break and pulverize and are generally not used outdoors, but they dry quickly and have good chemical resistance. Alkyd enamels have the most widely used physical properties such as chemical resistance and weatherability, formability, hardness, and luster.
2, air drying enamel:
Usually made of intoxicated acid, it uses oxygen in the air to cure after reaction. The performance of drunk acid enamel depends on the type and amount of oil used. The longer the oil dries, the longer the enamel will dry. When drying conditions are required, paints with a long drying time generally have good surface durability. These paints are mostly used for outdoor metal signs.
3, dissolved volatile ink:
Only rely on solvents to achieve dryness. The final properties of the coating are based on the properties of the material inherent in the polymer before it is formulated into a liquid. This type of polymer contains thermoplastic acrylic acid. Screen-printing inks that are based on the nature of their use are often subject to dissolution damage. There are some acrylics that are insoluble in gasoline and alcohol, where the film surface can come into contact. Therefore, inks based on thermoplastic acrylic, ethylene, and other soluble polymers are mostly used on plastic substrates.
4, double liquid ink:
Common epoxy or polyurethane, although there are many other species. The dual-liquid system often used in materials is the most sensible choice for saving energy, and its coating quality is high, but the mixing is inconvenient. In addition, it should be selected according to the use of the product. If the product may be used outdoors, and it is also injected with some flexibility, then the urethane ink mainly composed of aliphatic hydrocarbons is used. The two-liquid epoxy resin inks on the market today have almost the same performance as baked enamels, but their formability is not good enough.
5, ink additives:
Like other inks, screen printing inks for metals also contain additives, which are small amounts of chemicals that are produced during production to improve the performance of the ink film. Some can accelerate curing or initiate curing, while others can cause bubbles to burst, and ink Uniform quality, reducing the possibility of conjunctiva. The manufacturer mixes the additives with the ink according to a specific recipe. The printer needs to dilute the ink to a consistency suitable for printing.
Fourth, printing
The quality of screen printing [encyclopedia] and the thickness of the ink layer are closely related to the thickness of the screen, the viscosity of the ink, the hard charge of the squeegee, the angle, and the method of plate making.
1, silk plate and positioning: aluminum plate material with three-point positioning. For color printing, light color is printed first and dark color is printed again.
2. The distance between the printing plate and the substrate is 1-2mm, and the distance is related to the choice of the screen. The nylon screen has good elasticity and high elasticity, usually 2-3mm.
3, polyurethane rubber board scraper, the hardness of 70-75 degrees, thickness of 8-9 mm, scraper angle of 70 degrees when printing is appropriate, scraper speed should be uniform linear motion.
4. Appropriate protective film: After the printed signage, in order to avoid trauma during cutting and transportation, the surface should be provided with a transparent pressure-sensitive adhesive protective film, and a double-sided adhesive tape should be attached to the back surface.
5, cutting: with a small shear bed, molding available hole positioning or edge positioning stamping.
First, screen printing system board
1, paint film engraving method:
It is a kind of manual plate making method and it is relatively simple. It can print monochrome and non-exquisite monochrome designs and text.
(1) Sprayed stenciled film paper: Stick the tracing paper with a paste on a flat wood plate. Use a screed to adjust the rubber water to 1 part (volume ratio) and 1 part of the gasoline. Apply evenly on the paper. , Dry after spraying soft varnish 3-5 times, after each spraying, in the oven with 40 degrees to 50 degrees drying, the film thickness is sprayed to 5 ~ 6 mm is appropriate, the film should be bright, uniform, no bubbles No blemishes.
(2) Engraving pattern: Put the paint film on the figure, and then use a carving knife, a circle knife and a ruler to sculpt according to the figure, gently remove the paint film.
(3) Reposting: After engraving the graphics, it can be reposted on the screen frame that was made in advance. The method is to press the well-formed film under the mesh frame, and gently rub it with a little dilute material on the cotton until the paint film sticks to the mesh. After drying for a few minutes, remove the tracing paper. If the paper is not completely removed, wipe it with cotton. The blank part is coated with nitrocellulose and the mesh of the screen is plugged. Allow to print after drying.
2, carbon paper printing method:
It is also a relatively simple manual plate making method.
(1) Photosensitive paper: Photosensitive paper is a kind of mixture of carbon paper made of oxygen and made of thick paper. The size of the pattern is cut and ready for use.
(2) Sensitization: soak in a solution of 500 milliliters and 20 grams of ammonium dichromate for 3-5 minutes, remove the carbon paper, and drain the water.
(3) Exposure: Put the carbon paper flat on the cleaned glass with the film facing up, covering the positive polyester film base plate on the top and exposing with a printing machine. The exposure time is 8-12 minutes.
(4) Development: Exposure for 40 minutes in 40 to 50 degrees warm water, so that the film and the positive plate are naturally detached from the zinc oxide base paper, and carefully developed with warm water until the text is clear.
(5) Reposting: Put the prepared version under the mesh frame of the wire mesh that has been stretched beforehand, cover several layers of newspapers above the wire mesh, and press the glass plate with a weight of 1-2 kg/cm2. When the film and the screen stick securely, remove heavy objects and newspapers, use the electric oven to dry the film, and then remove the original paper, the film pattern is transferred to the screen. Carefully check the graphics for defects. After qualifying, apply a layer of nitro-chrome paint on the screen surrounding the pattern to protect the screen printing plate on the plate table for printing. The scope of application of this plate making method is the same as that of the film engraving method.
3, photosensitive plate method: silk screen printing plate used by the higher accuracy requirements, generally use advanced direct, indirect, straight between the three photosensitive plate method.
A, direct plate method:
(1) Aluminium frame is used for post frame, no stretching net is required for maneuverability stretch net, air pressure is 5-6 kg/cm2, acetal glue is used to stick net, tension degree of tension is measured with tension, tension is 5-7 kg, sinks The size should be less than 2mm.
(2) Wash the wire mesh: Use detergent, detergent, ethanol, etc. as cleansing agent, wash both sides of the wire mesh, rinse with clean water, and dry it after hot air drying. The purpose is to make the net bond better with the photo resist.
(3) Scraping bucket (coating bucket, applicator): The scraper coated with sensitized rubber can be made of stainless steel, and scrapers can also be made of organic glass plates. Its length is generally slightly smaller than the inner diameter of the screen frame (several scrapers of different lengths are paired together). The edge of the scraper must be thin and not edged, smooth and straight, and does not allow defects such as bumps, burrs, and scars, affecting the quality of the plate. When applying the screen-sensitive adhesive, it is necessary to dry it once every three times for three times, until the film reaches the required thickness, and then perform exposure.
(4) The temperature of the drying oven, ideally with a temperature-controlled drying oven. The drying temperature of the emulsion is generally controlled at about 40 degrees. Too long baking time or too high temperature will affect the quality of the photosensitive layer.
(5) Security lighting: The lighting source of the studio generally uses orange, yellow or red light as the security light, but from the visual point of view, the orange light source is more comfortable. Its brightness is suitable to clearly see everything.
(6) Inspection of the bottom plate: Before the printing plate, the bottom plate must be inspected carefully, including whether the dust on the plate surface, the darkness of the bottom plate, the line breakage, the sand hole defect, etc., and the positive and negative of the image text meet the requirements.
B. Indirect method:
(1) Prepare the frame and photosensitive film: Clean the frame (the nylon thread is 220-260 mesh) with a 10% aqueous sodium phosphate solution to remove oil stains.
The line network photosensitive film is a kind of photosensitive adhesive mainly composed of polyenol glue. The film is coated with gelatin as the main sensitizer on the base of 0.12-0.06 mm transparent plastic film. The size of the pattern is used before being used. Each side is wide. Take out 20 mm and wipe the dirt on the membrane with a cloth.
(2) Exposure: The film and the bottom plate are pressed tightly in the printing machine and exposed with a carbon or xenon lamp. The distance between the frame and the light source is 50-60 cm and the exposure time is 2-6 minutes.
(3) Development: After exposure, the film is placed on a flat plate, and the omentum is soaked in warm water for 1-2 minutes. The water is sprayed on the sprinkler. The non-photosensitive part (graphic part) is printed with water, and the resulting film is developed. Until the graphics are clear.
(4) affixed to the film: the film surface of the film is exposed on the screen, the back of the film with a rubber board or other straight, gently scraping, so that the film and the net contact firmly, immediately placed in the oven, at the temperature Baking for 8-12 minutes under the condition of 55±2 degrees, after drying, the mesh frame is fixed on the plate for test printing.
(6) Film removal method: In the process of exposure and development, when the unsatisfied version is found, immediately use warm water to brush off the film and re-create it. If the plate is dry or it is removed after production for a period of time, use one part of industrial sodium hypochlorite and water and soak for 10-20 minutes. Or 5% sodium hydroxide aqueous solution heat treatment screen, you can remove the film.
C, straight between the plate method:
Straight line method is a mixed plate method of direct method and indirect method. The difference between it and indirect method is that indirect method is first applied to the film on the film and then transferred to the screen, and the direct method is to first film film. Transfer to the screen and make an image after exposure.
Second, the pre-processing of printing materials
The label printing materials mainly include aluminum, copper, stainless steel and aluminum. The amount of organic glass is the most. There are also plastic, polyester, paper and so on.
Aluminium signage is a widely used type of signage, with characteristics of beauty, brightness, high hardness, good wear resistance, wide application, and large amount. For machinery, electronics, instruments, meters, household appliances, daily hardware, watches, daily cosmetics packaging.
There are various methods for the pretreatment of the aluminum substrate. According to the application, there are mainly degreasing, sandblasting, wire drawing, polishing, and oxygen grease.
1. Degreasing: In order to make the surface of the aluminum substrate have certain ink affinity, it is necessary to remove the oil layer and oil on the surface, and wipe it with cotton yarn and gasoline. Chemical degreasing can also be carried out with an alkaline solution, such as sodium sulfate 30-50 g/L, sodium phosphate 40-60 g/L, sodium silicate 10-15 g/L, dipping 2-5 at a temperature of 60-70C. Degreasing in minutes.
2, sandblasting: sandblasting is to improve the adhesion of ink and metal materials, usually using a special sandblasting machine spray treatment, if the 0.5-1 mm thick aluminum plate, sandblasting sand with a diameter of 0.05-0.15 mm, also Available river sand, sieved and used.
3, drawing: also known as skein processing, is to use the method of mechanical friction on the surface of the aluminum plate to produce a fine linear line. It is a relatively new surface decorative treatment process that can overcome defects such as scratches on aluminum surfaces. Improve the use of materials. There are two types of wire drawing, such as stainless steel wire brush with a diameter of 0.1 mm or a brush with a scouring pad, and nylon belts.
4, polishing: to overcome the surface defects of aluminum-based materials, improve the surface finish. Polishing is divided into mechanical polishing and chemical polishing. Mechanical polishing uses a cloth wheel polisher, and the chemical polishing is performed in an acidic solution such as sulfuric acid 15%, nitric acid 10%, temperature 90-100 degrees, and time 2-3 minutes.
5. Oxidation: The surface of the polished aluminum plate has residual polishing soap, which is wiped off with a veil of yam and then chemically deoiled. Then it is immersed in a nitric acid solution (1:1 ratio of nitric acid and water) and removed after 10 minutes. Then placed in an oxidation tank for electrochemical oxidation. Oxidized liquid formula: nitric acid 160-200 g/ml, temperature 10-20 degrees, time 30 minutes.
The well-oxidized aluminum plate is fully washed and air-dried, and a layer of uniform oxide layer, ie, an oxide film, is formed on the surface, and contamination of the contaminants should be avoided. Good oxidation of aluminum is best to immediately print [encyclopedia microblogging], if not immediately printed, use soft paper septa wrapped or directly on the air frame, storage time can not exceed one week.
The oxide layer on the surface of the aluminum plate can adsorb dyes, moisture, and other salts, so the surface is not touched by hand or with oily material during screen printing. When the ink is printed on the oxide layer, the ink penetrates into the pores. The warming of the next step is to accelerate the ink into the pores until all the ink-covered surface pores have been filled.
The ink printed on the surface rarely spreads or does not spread, ensuring the accuracy and clarity of the text and the pattern.
6, closed: Its role is to firmly seal the ink in the pores, never overflow or spread. For areas that are not filled with ink, the function of the seal is to fill the gaps of the oxide film and make it impervious to water and enhance the corrosion resistance of the surface. Nickel sulfate solution is generally used for sealing. Formula: 10-12 ml of nickel vanadate, temperature 80-90 degrees, 10-15 minutes. After sealing the hole, touch the surface with hand or other oily thing and wash it off with a general cleaning agent.
Third, silk screen printing ink (paint)
In today's metal plate or non-metal screen printing, more printing inks can be used, but it is not easy to select suitable inks (coatings). There are the following inks commonly used for silk screen printing:
1, baking enamel:
It is a single-liquid formulation that cross-links when heated and has good storage properties. Can be stored for 6 months to a year. Has a good finish, wear resistance, chemical resistance and weatherability, and thus the most commonly used. Alkyd, acrylic and polyester have these properties. Epoxy resins tend to break and pulverize and are generally not used outdoors, but they dry quickly and have good chemical resistance. Alkyd enamels have the most widely used physical properties such as chemical resistance and weatherability, formability, hardness, and luster.
2, air drying enamel:
Usually made of intoxicated acid, it uses oxygen in the air to cure after reaction. The performance of drunk acid enamel depends on the type and amount of oil used. The longer the oil dries, the longer the enamel will dry. When drying conditions are required, paints with a long drying time generally have good surface durability. These paints are mostly used for outdoor metal signs.
3, dissolved volatile ink:
Only rely on solvents to achieve dryness. The final properties of the coating are based on the properties of the material inherent in the polymer before it is formulated into a liquid. This type of polymer contains thermoplastic acrylic acid. Screen-printing inks that are based on the nature of their use are often subject to dissolution damage. There are some acrylics that are insoluble in gasoline and alcohol, where the film surface can come into contact. Therefore, inks based on thermoplastic acrylic, ethylene, and other soluble polymers are mostly used on plastic substrates.
4, double liquid ink:
Common epoxy or polyurethane, although there are many other species. The dual-liquid system often used in materials is the most sensible choice for saving energy, and its coating quality is high, but the mixing is inconvenient. In addition, it should be selected according to the use of the product. If the product may be used outdoors, and it is also injected with some flexibility, then the urethane ink mainly composed of aliphatic hydrocarbons is used. The two-liquid epoxy resin inks on the market today have almost the same performance as baked enamels, but their formability is not good enough.
5, ink additives:
Like other inks, screen printing inks for metals also contain additives, which are small amounts of chemicals that are produced during production to improve the performance of the ink film. Some can accelerate curing or initiate curing, while others can cause bubbles to burst, and ink Uniform quality, reducing the possibility of conjunctiva. The manufacturer mixes the additives with the ink according to a specific recipe. The printer needs to dilute the ink to a consistency suitable for printing.
Fourth, printing
The quality of screen printing [encyclopedia] and the thickness of the ink layer are closely related to the thickness of the screen, the viscosity of the ink, the hard charge of the squeegee, the angle, and the method of plate making.
1, silk plate and positioning: aluminum plate material with three-point positioning. For color printing, light color is printed first and dark color is printed again.
2. The distance between the printing plate and the substrate is 1-2mm, and the distance is related to the choice of the screen. The nylon screen has good elasticity and high elasticity, usually 2-3mm.
3, polyurethane rubber board scraper, the hardness of 70-75 degrees, thickness of 8-9 mm, scraper angle of 70 degrees when printing is appropriate, scraper speed should be uniform linear motion.
4. Appropriate protective film: After the printed signage, in order to avoid trauma during cutting and transportation, the surface should be provided with a transparent pressure-sensitive adhesive protective film, and a double-sided adhesive tape should be attached to the back surface.
5, cutting: with a small shear bed, molding available hole positioning or edge positioning stamping.
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