Screen printing platemaking, printing process, the performance of the screen has the following basic requirements:
1. High tensile strength. Tensile strength refers to the ability of a screen to resist breaking (breaking) when it is pulled. In addition, the strength of the screen after moisture absorption should be small.
2. The elongation at break is small. Elongation refers to the ratio of the amount of elongation when the screen breaks under a certain tension to the original length, expressed as a percentage. The elongation is large and the plane stability is poor, but the screen also requires sufficient elasticity under a certain tension (about 3%).
3. Resilience is good. Resilience means that the screen stretched a certain length (such as after elongation of 3%), when the external force is released, the length of its recovery ability, called the elongation recovery, the greater the value of the better, rebound, clear edges after printing.
4. Temperature stability and humidity change stability.
5. The ink's passing performance is good.
6. Good resistance to chemicals.
7. See the project list for specific items.
Section II: Frames and Stretching
one. Frame material selection
General use of LY12, LF2 and other hard alloy aluminum square tube, size selection width 20mm, thickness 20mm, four corners by argon arc welding or riveting processing. The metal frame has high precision and dimensional stability.
two. Screen material choice
At present, nylon mesh and polyester mesh are the most used. Nylon mesh is poor in heat resistance, easily deformed by heat after being heated, making the tension non-uniform, affecting the quality of screen printing. Bonding stretch net or screen stencil production should not be high-temperature baking. Polyester mesh has good heat resistance, dimensional stability, and the pattern does not change greatly due to changes in temperature and humidity. In order to ensure the accuracy of screen printing graphics, it is best to use monofilament polyester screen. At the same time, screens with a higher number of meshes, smaller wire diameters, and smaller meshes should be selected. The color of the screens should be yellow or brownish to prevent vignetting.
three. Stretch net
Pneumatic stretching machines are the best choices. The quality requirements for stretch nets are as follows:
1. Stretch net tension is suitable and uniform
(1) When using a pneumatic stretch net to reach the tension requirement, it must be allowed to stand for 3-6 hours and then stretch the net;
(2) Stretch a good network for a minimum of 24 hours or more, especially for large cargo or machine-printed nets to ensure equal stress at all points and prevent deformation. The higher the screen size, the longer the screen is required to be placed. It is usually 2-3 days. After placement, the tension of the screen is stable, and the stress of the name points is equal, so as to ensure that the screen is not deformed and is not easily damaged.
2. Latitude and longitude meshes remain vertical
3. Prevents relaxation
four. Screen stencil plate making process
At present, the most commonly used method is the direct method for making screen templates. In this production process, attention should be paid to the proper thickness of the sizing coating and uniform sizing. Strict control of drying, exposure, and development should be used to obtain high-quality screen templates.
Section III: Screen Printing Requirements for Photosensitive Materials
Suitable sensitized spectral range, generally suitable for 340~440μm, sensitive wavelength, plate making operation and printing plate storage require strict dark room conditions; wavelength is too short, light source selection, personnel protection will become more difficult; high sensitivity , Can achieve energy-saving, rapid plate-making purposes; good performance, high resolution, good stability, it is easy to store, feeling less waste.
2. Screen printing requirements for photosensitive materials: The photographic film formed by the photosensitive material should be adapted to the performance requirements of different types of inks, has a considerable resistance to printing, can withstand the scraping pressure of a considerable number of scraping inks, and has a good combination with screens. No stripping failure during printing; easy peeling, not easy to produce ghosting, which is conducive to the regeneration of screen plate material. For non-drying inks, it is required that the photosensitive film reach a certain thickness of 10 to 40 μm on the printing surface, which is about 1 to 2 sheets of 80 g copy paper.
Section 4: Shaiban Light Sources and Equipment
one. Shaiban light source selection.
Photolithography is a very important process in photolithography process. If the correct selection and use of printing plate light source, to improve the quality of the screen printing plate, effectively save energy, simplify the operation, maintain the operator's health, reduce costs is of great significance. Because of the different types of photosensitive resin photosensitive materials, it is necessary to choose to use a light source that meets the needs of various photosensitive materials.
At present, the color sensitivity of various screen-sensitive materials we use is mostly distributed between 250 and 510 μm. Therefore, theoretically speaking, any light source with a peak wavelength of 250-510 μm on the energy emission curve of the emission spectrum can be used for screen printing. In addition, when printing, it is necessary to fully study the size of the plate, the output power of the light source, the distance between the plate and the light source, and pay special attention to the function of the light reflecting plate.
two. When choosing a light source
1. The emission spectrum of the light source should match the absorption characteristics and the color rendering properties of the photosensitive material. The energy of light varies with the frequency of the wavelength. The shorter the wavelength, the higher the frequency, and the greater the photon energy. When the light is absorbed by the material in the process of radiation, since the photon has a certain amount of energy, the material undergoes physical and chemical changes. The chemical reaction caused by the light energy is called a photochemical reaction. By photochemical matching, it is meant that the distribution of the spectral output of the selected light source should match the spectral chrominance of the photosensitive material. That is, the wavelength range in which the light-sensitive material absorbs light and the photochemical reaction occurs is exactly the output range of the light source light emission spectrum, and the maximum absorption peak of the light-sensitive material happens to be at the output peak of the light source. In this way, the light energy of the light source is absorbed by the photosensitive material as much as possible and a photochemical reaction takes place.
2. High luminous efficiency and high intensity. With other conditions unchanged, the greater the power and luminous efficiency of the light source, the greater the luminous intensity or brightness, the higher the illumination of the exposed surface, and the shorter the time required for the photosensitive material to obtain the same exposure. .
3. Light source heat radiation is small. To ensure that the light source has sufficient luminous intensity or bright light, the thermal radiation of the light source should be as small as possible. When using a powerful high-power light source, forced cooling (air-cooled, water-cooled) and other measures must be taken to the lamp, and other measures should be taken to expose the photosensitive material to a temperature below 32°C.
4. Uniform luminous intensity. The luminous intensity of the illuminated surface of the light source should be as uniform as possible. The design of the exposure device shall ensure that the illumination difference of the exposed areas of the photosensitive material does not exceed 15%. Light source environment adaptability. The light source should have strong environmental adaptability, and it can work normally under various temperature, air flow and voltage variations. Of course, in actual production, it is unrealistic to choose a light source that can fully meet the above requirements. The purpose of the above-mentioned selection principle is only to hope that the plate-making operator should consider the influence of the light source on the exposure quality of the photosensitive material when choosing to use the plate-making light source.
pay attention:
(1) When the number of fine mesh points is high, the exposure time is reduced by 5% on the basis of the above table. After exposure, the exposure is performed again (without film) to ensure the printing durability of the printing plate. The time is the normal exposure time. 2 to 3 times.
(2) If the photosensitive paste is a thick-film photosensitive paste to extend the exposure time, such as 40 microns thick 120-head to be extended by 50%, and so on.
(3) If you want to do high-quality printing, use EXPOSENRECALCULATOR to measure the precise exposure time.
5. development. The exposed plate is immersed in water for a minute or two. The non-photosensitive part, such as the screen plate, is constantly shaken to absorb moisture. After swelling, it is developed by rinsing with water. The development should use a strong pressure gun but in any case must be completely dissolved together with the unsensitized part as much as possible within a short time. When the pattern is fine, 8 to 10 times of the magnifying glass is used to check if the subtle part is completely empty. It must be completely empty. After the development, use a clean, large white paper, sponge or hair dryer to quickly remove the moisture and dry it. The principle of control is that under the premise of being wet, the shorter the time, the better. If the time is too long, the film's wet expansion will punish the image's clarity. If the time is too short, the development will not be thorough, and it will leave behind blindfolded mesh holes, resulting in the waste version. Mongol is a very thin layer of photosensitive adhesive residue, easy to appear in the details of the image, highly transparent, difficult to distinguish with the water film, often mistaken for clear.
6. dry. The developed screen plate should be placed in a dust-free dry box and blown with warm air. The drying temperature of the screen-type drying box can generally be controlled at about 40 degrees. When drying, the moisture of the surface of the screen should be blown off in advance so as to prevent the moisture from flowing down the surface of the screen to produce residual adhesive and blemishes, which will affect the sharpness of the line edges and the absence of fine dots.
8. an examination. Screen inspection is the final process of the entire plate making work and it is also an extremely important process. The small defects exposed after the development can be corrected by revision. If a large defect occurs, it must be re-plated. In the quality inspection of the screen, at least the following questions should be emphasized: (1) The exposure time is accurate. In addition to measuring the degree of film hardening with a density ladder, you can also see how the fineness of the bottom plate is reproduced on the screen. We must observe whether the lines are complete, whether the edges are clear, whether the sawtooth shape is serious, the fine meshes are transparent, etc. . (2) The mesh is completely transparent. Check the quality of the screen printing plates, including whether the images are all developed or not, whether there are glitches, lines, broken pens, and broken meshes, etc. If the above conditions are found, promptly adopt various methods to make up the situation. Consider remaking the plate to ensure print quality. (3) Test the adaptability of various photosensitive materials. Check for omentum and blisters should be remedied in time. The four-sided screen is closed. Check the printing orientation markings for compliance with printing requirements.
Section VII: Problems and Causes of Direct Platemaking
1. The loss of photosensitive film during development cannot be made into a plate. (1) Underexposure. (2) Insufficient or ineffective dose of photosensitizer, reduced sensitivity.
2. The full-page image produces a slight ash. (1) The work place in the coating and drying process of the photosensitive liquid is excessively bright. (2) Insufficient exposure time and insufficient development. (3) Overheating occurs when part of the photosensitive liquid is applied and dried. (4) The exposure time is too long.
3. The subtle part of the image is not developed. (1) The exposure time is too long. (2) The positive and negative sides are reversed, and the positive film and the photosensitive film are not well combined. (3) Insufficient screen treatment. (4) The photosensitive film is too thick and the type of photoresist is not properly selected or the photoresist is ineffective.
4. The coated screen plate contains a lot of air bubbles. (1) Insufficient screen degreasing treatment. (2) Clean the screen before coating the photosensitive adhesive. (3) The temperature difference between screen drying and photo-resist in the coating process is large. (4) The storage temperature of the photoresist is too high. (5) Photosensitive adhesive and coating layer are too thin. (6) The coating speed is not uniform.
5. There are too many pin holes in the layout. (1) Dust is the main cause (2) There is a self-foaming of the photosensitive liquid. (3) When using a coating squeegee, the coating squeegee moves too quickly and is prone to blistering to produce pinholes. (4) An excess of photosensitizer can also produce pinholes. (5) The coated surface is very easy to get dusty. Therefore, it is necessary to keep the workplace clean. For example, the plan glass surface, the positive surface and the photosensitive surface must be kept completely clean. (6) A small amount of octanol can be added as a defoamer to the photosensitive liquid.
6. Visible pores appear after screen printing plate development. (1) Whether high temperature drying is performed after the shadow. (2) Whether a sensitizer with a long preservation period was used. (4) Is there any dust in the emulsion? (5) Whether the sensitizer and the emulsion are mixed with sufficient stirring and used after the disappearance of bubbles. (6) It is appropriate to grasp the exposure time.
7. Photographic text resolution is not high after printing. (1) Whether the development is sufficient or not, and whether it is flushed with clean water after development. (2) The screen for secondary use has been cleaned before use. (3) Whether the screen is in a horizontal position and dry. (4) Whether or not to choose a high-resolution photosensitive adhesive.
Section VIII: Problems and Countermeasures Related to Accuracy in the Process of Plate Making
First, the reasons for the influence of platemaking precision are various and can be roughly classified into the following 15 points:
1. The screen includes the type of screen used, the height of the screen mesh, the fineness of the wire diameter, the size of the screen opening area, the size of the wire expansion and contraction, the method of weaving the screen, and the color of the screen.
2. The frame includes the material of the frame, the size of the frame, and the strength of the frame.
3. The size of the tension.
4. The choice of stretch angle.
5. Net frame and screen bonding method.
6. Wire mesh pretreatment.
7. Scraper material, scraper width, hardness, squeegee angle, edge state and net distance, squeegee pressure, etc. are all very important, should choose polyester rubber scraper. Scraper hardness is mostly in the range of Shore A60-80, the squeegee angle is 20-30 degrees, the edge must always be kept flat. The net distance is generally 2-4mm and the screen is parallel to the table. It is advisable to print the pressure to print clear graphics.
8. Photosensitive materials, including sensitivity level, resolution level, adhesion of photosensitive materials, expansion and contraction rate of photosensitive film, photosensitive film thickness and photosensitive film hardness, water resistance, solvent resistance and friction resistance, and resistance to printing force High and low.
9. The blending time of the sensitizer, the time after blending.
10. Drying methods and conditions include drying temperature, humidity, and drying time.
11. In terms of printing, Yang used light sources, the length of exposure time, and the distance between light sources.
12. The density of the resulting backsheet.
13. In terms of development, the development method includes: water development, warm water development, and drug development; development conditions: temperature, soaking time, type and use of a water sprayer, and the like.
14. Drying temperature and time after development.
15. Double exposure time selection and revision.
Second, the representative problems in the process of plate making and solutions.
1. The image has low resolution and levels are lost.
Causes:
(1) When printing, the bottom plate is not in contact with the film.
(2) The quality of the bottom plate (positive picture) is not good.
(3) The quality of the photosensitive adhesive itself is poor and the resolution is low.
(4) Improper selection of light sources.
(5) The mesh size is too low.
(6) Improper development and processing.
The solution:
(1) Use vacuum adsorption or other means to make them in close contact.
(2) Check the plate density and image quality.
(3) Select high-quality photosensitive adhesive.
(4) Use a light source that matches the spectral wavelength of the photoresist.
(5) Increase the number of screen meshes.
(6) Check the developing flushing procedure and adjust the water pressure and water temperature.
2. The edge of the image has poor resolution.
Causes:
(1) When printing, the bottom plate is not in contact with the film.
(3) Light scattering during exposure.
(4) uneven film coating.
(5) The number of meshes selected for the image is too low.
The solution:
(1) Closed by vacuum adsorption or other means.
(2) Rinse the image from both sides until it is clean and clear.
(3) Use colored wire mesh.
(4) Check the coating process and increase the screen tension.
(5) Increase the number of screen meshes.
3. Image thin lines and small dots disappear.
Causes:
(1) It is not true that the bottom plate and the screen film are attached during the printing.
(2) The density of the bottom plate is insufficient.
(3) The exposure time is not long.
(4) Irradiation of the light source is not uniform.
(5) Insufficient development.
1. High tensile strength. Tensile strength refers to the ability of a screen to resist breaking (breaking) when it is pulled. In addition, the strength of the screen after moisture absorption should be small.
2. The elongation at break is small. Elongation refers to the ratio of the amount of elongation when the screen breaks under a certain tension to the original length, expressed as a percentage. The elongation is large and the plane stability is poor, but the screen also requires sufficient elasticity under a certain tension (about 3%).
3. Resilience is good. Resilience means that the screen stretched a certain length (such as after elongation of 3%), when the external force is released, the length of its recovery ability, called the elongation recovery, the greater the value of the better, rebound, clear edges after printing.
4. Temperature stability and humidity change stability.
5. The ink's passing performance is good.
6. Good resistance to chemicals.
7. See the project list for specific items.
Section II: Frames and Stretching
one. Frame material selection
General use of LY12, LF2 and other hard alloy aluminum square tube, size selection width 20mm, thickness 20mm, four corners by argon arc welding or riveting processing. The metal frame has high precision and dimensional stability.
two. Screen material choice
At present, nylon mesh and polyester mesh are the most used. Nylon mesh is poor in heat resistance, easily deformed by heat after being heated, making the tension non-uniform, affecting the quality of screen printing. Bonding stretch net or screen stencil production should not be high-temperature baking. Polyester mesh has good heat resistance, dimensional stability, and the pattern does not change greatly due to changes in temperature and humidity. In order to ensure the accuracy of screen printing graphics, it is best to use monofilament polyester screen. At the same time, screens with a higher number of meshes, smaller wire diameters, and smaller meshes should be selected. The color of the screens should be yellow or brownish to prevent vignetting.
three. Stretch net
Pneumatic stretching machines are the best choices. The quality requirements for stretch nets are as follows:
1. Stretch net tension is suitable and uniform
(1) When using a pneumatic stretch net to reach the tension requirement, it must be allowed to stand for 3-6 hours and then stretch the net;
(2) Stretch a good network for a minimum of 24 hours or more, especially for large cargo or machine-printed nets to ensure equal stress at all points and prevent deformation. The higher the screen size, the longer the screen is required to be placed. It is usually 2-3 days. After placement, the tension of the screen is stable, and the stress of the name points is equal, so as to ensure that the screen is not deformed and is not easily damaged.
2. Latitude and longitude meshes remain vertical
3. Prevents relaxation
four. Screen stencil plate making process
At present, the most commonly used method is the direct method for making screen templates. In this production process, attention should be paid to the proper thickness of the sizing coating and uniform sizing. Strict control of drying, exposure, and development should be used to obtain high-quality screen templates.
Section III: Screen Printing Requirements for Photosensitive Materials
Suitable sensitized spectral range, generally suitable for 340~440μm, sensitive wavelength, plate making operation and printing plate storage require strict dark room conditions; wavelength is too short, light source selection, personnel protection will become more difficult; high sensitivity , Can achieve energy-saving, rapid plate-making purposes; good performance, high resolution, good stability, it is easy to store, feeling less waste.
2. Screen printing requirements for photosensitive materials: The photographic film formed by the photosensitive material should be adapted to the performance requirements of different types of inks, has a considerable resistance to printing, can withstand the scraping pressure of a considerable number of scraping inks, and has a good combination with screens. No stripping failure during printing; easy peeling, not easy to produce ghosting, which is conducive to the regeneration of screen plate material. For non-drying inks, it is required that the photosensitive film reach a certain thickness of 10 to 40 μm on the printing surface, which is about 1 to 2 sheets of 80 g copy paper.
Section 4: Shaiban Light Sources and Equipment
one. Shaiban light source selection.
Photolithography is a very important process in photolithography process. If the correct selection and use of printing plate light source, to improve the quality of the screen printing plate, effectively save energy, simplify the operation, maintain the operator's health, reduce costs is of great significance. Because of the different types of photosensitive resin photosensitive materials, it is necessary to choose to use a light source that meets the needs of various photosensitive materials.
At present, the color sensitivity of various screen-sensitive materials we use is mostly distributed between 250 and 510 μm. Therefore, theoretically speaking, any light source with a peak wavelength of 250-510 μm on the energy emission curve of the emission spectrum can be used for screen printing. In addition, when printing, it is necessary to fully study the size of the plate, the output power of the light source, the distance between the plate and the light source, and pay special attention to the function of the light reflecting plate.
two. When choosing a light source
1. The emission spectrum of the light source should match the absorption characteristics and the color rendering properties of the photosensitive material. The energy of light varies with the frequency of the wavelength. The shorter the wavelength, the higher the frequency, and the greater the photon energy. When the light is absorbed by the material in the process of radiation, since the photon has a certain amount of energy, the material undergoes physical and chemical changes. The chemical reaction caused by the light energy is called a photochemical reaction. By photochemical matching, it is meant that the distribution of the spectral output of the selected light source should match the spectral chrominance of the photosensitive material. That is, the wavelength range in which the light-sensitive material absorbs light and the photochemical reaction occurs is exactly the output range of the light source light emission spectrum, and the maximum absorption peak of the light-sensitive material happens to be at the output peak of the light source. In this way, the light energy of the light source is absorbed by the photosensitive material as much as possible and a photochemical reaction takes place.
2. High luminous efficiency and high intensity. With other conditions unchanged, the greater the power and luminous efficiency of the light source, the greater the luminous intensity or brightness, the higher the illumination of the exposed surface, and the shorter the time required for the photosensitive material to obtain the same exposure. .
3. Light source heat radiation is small. To ensure that the light source has sufficient luminous intensity or bright light, the thermal radiation of the light source should be as small as possible. When using a powerful high-power light source, forced cooling (air-cooled, water-cooled) and other measures must be taken to the lamp, and other measures should be taken to expose the photosensitive material to a temperature below 32°C.
4. Uniform luminous intensity. The luminous intensity of the illuminated surface of the light source should be as uniform as possible. The design of the exposure device shall ensure that the illumination difference of the exposed areas of the photosensitive material does not exceed 15%. Light source environment adaptability. The light source should have strong environmental adaptability, and it can work normally under various temperature, air flow and voltage variations. Of course, in actual production, it is unrealistic to choose a light source that can fully meet the above requirements. The purpose of the above-mentioned selection principle is only to hope that the plate-making operator should consider the influence of the light source on the exposure quality of the photosensitive material when choosing to use the plate-making light source.
pay attention:
(1) When the number of fine mesh points is high, the exposure time is reduced by 5% on the basis of the above table. After exposure, the exposure is performed again (without film) to ensure the printing durability of the printing plate. The time is the normal exposure time. 2 to 3 times.
(2) If the photosensitive paste is a thick-film photosensitive paste to extend the exposure time, such as 40 microns thick 120-head to be extended by 50%, and so on.
(3) If you want to do high-quality printing, use EXPOSENRECALCULATOR to measure the precise exposure time.
5. development. The exposed plate is immersed in water for a minute or two. The non-photosensitive part, such as the screen plate, is constantly shaken to absorb moisture. After swelling, it is developed by rinsing with water. The development should use a strong pressure gun but in any case must be completely dissolved together with the unsensitized part as much as possible within a short time. When the pattern is fine, 8 to 10 times of the magnifying glass is used to check if the subtle part is completely empty. It must be completely empty. After the development, use a clean, large white paper, sponge or hair dryer to quickly remove the moisture and dry it. The principle of control is that under the premise of being wet, the shorter the time, the better. If the time is too long, the film's wet expansion will punish the image's clarity. If the time is too short, the development will not be thorough, and it will leave behind blindfolded mesh holes, resulting in the waste version. Mongol is a very thin layer of photosensitive adhesive residue, easy to appear in the details of the image, highly transparent, difficult to distinguish with the water film, often mistaken for clear.
6. dry. The developed screen plate should be placed in a dust-free dry box and blown with warm air. The drying temperature of the screen-type drying box can generally be controlled at about 40 degrees. When drying, the moisture of the surface of the screen should be blown off in advance so as to prevent the moisture from flowing down the surface of the screen to produce residual adhesive and blemishes, which will affect the sharpness of the line edges and the absence of fine dots.
8. an examination. Screen inspection is the final process of the entire plate making work and it is also an extremely important process. The small defects exposed after the development can be corrected by revision. If a large defect occurs, it must be re-plated. In the quality inspection of the screen, at least the following questions should be emphasized: (1) The exposure time is accurate. In addition to measuring the degree of film hardening with a density ladder, you can also see how the fineness of the bottom plate is reproduced on the screen. We must observe whether the lines are complete, whether the edges are clear, whether the sawtooth shape is serious, the fine meshes are transparent, etc. . (2) The mesh is completely transparent. Check the quality of the screen printing plates, including whether the images are all developed or not, whether there are glitches, lines, broken pens, and broken meshes, etc. If the above conditions are found, promptly adopt various methods to make up the situation. Consider remaking the plate to ensure print quality. (3) Test the adaptability of various photosensitive materials. Check for omentum and blisters should be remedied in time. The four-sided screen is closed. Check the printing orientation markings for compliance with printing requirements.
Section VII: Problems and Causes of Direct Platemaking
1. The loss of photosensitive film during development cannot be made into a plate. (1) Underexposure. (2) Insufficient or ineffective dose of photosensitizer, reduced sensitivity.
2. The full-page image produces a slight ash. (1) The work place in the coating and drying process of the photosensitive liquid is excessively bright. (2) Insufficient exposure time and insufficient development. (3) Overheating occurs when part of the photosensitive liquid is applied and dried. (4) The exposure time is too long.
3. The subtle part of the image is not developed. (1) The exposure time is too long. (2) The positive and negative sides are reversed, and the positive film and the photosensitive film are not well combined. (3) Insufficient screen treatment. (4) The photosensitive film is too thick and the type of photoresist is not properly selected or the photoresist is ineffective.
4. The coated screen plate contains a lot of air bubbles. (1) Insufficient screen degreasing treatment. (2) Clean the screen before coating the photosensitive adhesive. (3) The temperature difference between screen drying and photo-resist in the coating process is large. (4) The storage temperature of the photoresist is too high. (5) Photosensitive adhesive and coating layer are too thin. (6) The coating speed is not uniform.
5. There are too many pin holes in the layout. (1) Dust is the main cause (2) There is a self-foaming of the photosensitive liquid. (3) When using a coating squeegee, the coating squeegee moves too quickly and is prone to blistering to produce pinholes. (4) An excess of photosensitizer can also produce pinholes. (5) The coated surface is very easy to get dusty. Therefore, it is necessary to keep the workplace clean. For example, the plan glass surface, the positive surface and the photosensitive surface must be kept completely clean. (6) A small amount of octanol can be added as a defoamer to the photosensitive liquid.
6. Visible pores appear after screen printing plate development. (1) Whether high temperature drying is performed after the shadow. (2) Whether a sensitizer with a long preservation period was used. (4) Is there any dust in the emulsion? (5) Whether the sensitizer and the emulsion are mixed with sufficient stirring and used after the disappearance of bubbles. (6) It is appropriate to grasp the exposure time.
7. Photographic text resolution is not high after printing. (1) Whether the development is sufficient or not, and whether it is flushed with clean water after development. (2) The screen for secondary use has been cleaned before use. (3) Whether the screen is in a horizontal position and dry. (4) Whether or not to choose a high-resolution photosensitive adhesive.
Section VIII: Problems and Countermeasures Related to Accuracy in the Process of Plate Making
First, the reasons for the influence of platemaking precision are various and can be roughly classified into the following 15 points:
1. The screen includes the type of screen used, the height of the screen mesh, the fineness of the wire diameter, the size of the screen opening area, the size of the wire expansion and contraction, the method of weaving the screen, and the color of the screen.
2. The frame includes the material of the frame, the size of the frame, and the strength of the frame.
3. The size of the tension.
4. The choice of stretch angle.
5. Net frame and screen bonding method.
6. Wire mesh pretreatment.
7. Scraper material, scraper width, hardness, squeegee angle, edge state and net distance, squeegee pressure, etc. are all very important, should choose polyester rubber scraper. Scraper hardness is mostly in the range of Shore A60-80, the squeegee angle is 20-30 degrees, the edge must always be kept flat. The net distance is generally 2-4mm and the screen is parallel to the table. It is advisable to print the pressure to print clear graphics.
8. Photosensitive materials, including sensitivity level, resolution level, adhesion of photosensitive materials, expansion and contraction rate of photosensitive film, photosensitive film thickness and photosensitive film hardness, water resistance, solvent resistance and friction resistance, and resistance to printing force High and low.
9. The blending time of the sensitizer, the time after blending.
10. Drying methods and conditions include drying temperature, humidity, and drying time.
11. In terms of printing, Yang used light sources, the length of exposure time, and the distance between light sources.
12. The density of the resulting backsheet.
13. In terms of development, the development method includes: water development, warm water development, and drug development; development conditions: temperature, soaking time, type and use of a water sprayer, and the like.
14. Drying temperature and time after development.
15. Double exposure time selection and revision.
Second, the representative problems in the process of plate making and solutions.
1. The image has low resolution and levels are lost.
Causes:
(1) When printing, the bottom plate is not in contact with the film.
(2) The quality of the bottom plate (positive picture) is not good.
(3) The quality of the photosensitive adhesive itself is poor and the resolution is low.
(4) Improper selection of light sources.
(5) The mesh size is too low.
(6) Improper development and processing.
The solution:
(1) Use vacuum adsorption or other means to make them in close contact.
(2) Check the plate density and image quality.
(3) Select high-quality photosensitive adhesive.
(4) Use a light source that matches the spectral wavelength of the photoresist.
(5) Increase the number of screen meshes.
(6) Check the developing flushing procedure and adjust the water pressure and water temperature.
2. The edge of the image has poor resolution.
Causes:
(1) When printing, the bottom plate is not in contact with the film.
(3) Light scattering during exposure.
(4) uneven film coating.
(5) The number of meshes selected for the image is too low.
The solution:
(1) Closed by vacuum adsorption or other means.
(2) Rinse the image from both sides until it is clean and clear.
(3) Use colored wire mesh.
(4) Check the coating process and increase the screen tension.
(5) Increase the number of screen meshes.
3. Image thin lines and small dots disappear.
Causes:
(1) It is not true that the bottom plate and the screen film are attached during the printing.
(2) The density of the bottom plate is insufficient.
(3) The exposure time is not long.
(4) Irradiation of the light source is not uniform.
(5) Insufficient development.
Glassware is a broad international spectrum of equipment used in the brewing and consumption of tea. Many components make up that spectrum, and vary greatly based upon the type of tea being prepared, and the cultural setting in which it is being prepared. This is often referred to as the tea ceremony, and holds much significance in many cultures, particularly in northwestern Europe and in eastern Asia.
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Wine |
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Material |
High borosilicate glass |
|
Technology |
Hand blown |
|
Volume |
50 to 5000ml or as your requirements |
|
Weight |
150 to 2000g and so on |
|
Sealing type |
Screw cap or cork |
|
Painting |
Any color as you requirement |
|
Quality control |
SGS, FDA, ISO9001, ISO14001 |
|
Deep processing |
Silk screen, decal, spray painting, electroplating, frosting, sand blasting. |
|
Delivery term |
EXW, FOB, CIF |
|
Payment terms |
T/T |
|
Lead time |
New design drawing confirm within 3days, Sample mold within 20 days, bulk molds within 30 days, produce in bulk within 30 days |
FAQ:
Q: Are you a manufacture or a trading company?
A: We are a manufacture which located in Chengdu city and Yibin city, Sichuan, China.
Q: Can you customize the products?
A: Yes, we are professional to customize glass bottle, we can design the new drawings and open the new molds according to your requirement.
Q: Do you provide free sample?
A: Yes, for cooperation sincerity, we are glad to provide you samples for free, but for new customer, the express cost need to be paid.
Q: What is your MOQ?
A: Our only standard for MOQ is a 40 feet container.
Q: How long is your sample lead time, mold need time and production lead time?
A: New design drawing confirm within 3 days, sample mold within 20 days, bulk molds within 30 days, produce in bulk within 30 days
Glassware
Glass Teaware,Opal Glass Teaware,Borosilicate Glass Teaware,Glass Teapot
SICHUAN YIBIN GLOBAL GROUP CO.,LTD. , https://www.globalglassbottle.com