1Q: What are the requirements of flexo platemaking on film? In order to ensure that the film and the surface of the plate can be in close contact, a matte film must be used. When the plate is made, the matte surface of the film is in close contact with the surface of the plate.
Ensure that the density of the translucent zone of the film is less than 0.08, so as to make the plate material have better light curing, making the pattern more robust, clear, and reaching a certain hardness.
The opacity zone blackness requirement is greater than 4.0 to ensure smooth reproduction of the plate base area and relief pattern. Too low film density will make the embossing height of the plate not enough.
2Q: What is a photopolymerization relief printing plate made of photosensitive resin material by exposure and rinsing.
Solid type: printing plates made of pre-formed photosensitive resin plate, used for mechanical molding, good flatness, molding shrinkage, dimensional stability.
Liquid Curing Type: The printing plate made of liquid photosensitive resin as plate making material has poor dimensional stability, and the layout shrinkage is greatly affected by temperature and humidity.
3Q: What are the requirements for the light source of the flexographic plate?
The light source used is an ultraviolet light source, the wavelength of the UV-A light source is 320-400 nm, and the wavelength of the UV-C light source is 280-320 nm.
4Q: The composition and requirements of the platesetter and UV-A UV exposure system should be selected with Philips UVA-R UV lamps, equipped with high-quality ballasts and starters, and only the main circuit power supply must be connected during exposure. The lamp can be activated instantaneously to achieve even exposure. Light intensity can reach 10-18mW/cm2.
Plate version system, wash brush should be selected soft brush corrosion resistance and toughness, plate washing mode is divided into several types, drum type, inline type, platform type requirements adjust the level of paste table and brush surface Contact, otherwise there will be uneven flushing or embossing phenomenon; drum type: UV polishing using roller type plate, can reduce the size of the resin glazing deformation to a minimum; inline: domestic introduction The state-of-the-art flexo platesetter can set plate thickness, plate wash time, solvent concentration, and can be finally cleaned and pre-baked. The solvent of washing plate is divided into common type and environment-friendly type, the common type solvent is proportioned by tetrachloroethylene and n-butanol, the specific gravity is about 1.41, and the environmental protection solvent is generally imported from U.S. DUPONT.
Drying system, due to solvent plate, plate expansion and deformation, and showing a certain degree of stickiness, so the plate must be placed in a drying drawer at 60 °C temperature and dry for 90 minutes, making the plate back to the thickness of the plate.
Post-processing, using a UV-C light source for de-tacking, the de-tacking time is determined based on the intensity of the light source and the concentration of the solvent, and then the UV-A light source is used for final curing.
5Q: Why use a solvent recovery machine after washing the waste liquid, can be distilled at high temperature and recycled to save the solvent, so that there can be enough fresh solvent to supplement the wash plate, so that the solvent during the process of polishing is kept to an ideal concentration. The maximum boiling point of the recovery machine can be as high as 220° C., the boiling point of the common solvent is 160° C., and the cooling temperature is 90° C. The capacity of 62 L generally takes 5-6 hours to complete. The boiling point of the environmentally friendly solvent is 200°C, and the capacity of 62L can be completed in 4 hours. Since the recovery temperature is much higher than that of ordinary solvents, a vacuum cooling system is needed to speed up the recovery.
6Q: How to make proofing of proofing and offset printing is somewhat more difficult because there are too many variables from platemaking to color reproduction in flexographic printing. The current advanced method of proofing is the use of DuPont's Cromalin proofing system. The system uses special proofing paper and ink.
7Q: What should you pay attention to in the sticker? Clean the plate cylinder and the back of the plate with alcohol so that the double-sided adhesive tape remains well-adhesive.
When pasting, the sticker surface should be affixed to the plate because the curved feature ensures a good and convenient plate without bubbles. At the overlap of the tail end of the tape, cutting is performed.
Choose a brand of good quality adhesive tape such as tesa tape (TESA), according to different graphic lines and dots to choose the density of tape (soft and hard tape), according to the printing gap, sleeve thickness, thickness of the plate to confirm the thickness of the tape. Test its compressibility and recovery, conformability, and stickiness.
The relationship between the plate and the adhesive tape is "hard and soft". A thin and hard plate with a soft gasket foam tape can achieve a very good printing effect.
8Q: How to choose the printing media first according to the print:
1 carton version, thickness 3.94-7mm, hardness 35-42 (Shore A);
2 plastic bag version, thickness 2.28-2.84mm, hardness 50-60 (Shore A);
3 Soft pack and trademark version 1.14-1.70mm, hardness 60-70 (Shore A).
The following points should be noted when selecting the plate material:
1 Exposure latitude in platemaking, because the brand performance of current domestic platesetters cannot be unified, and the light intensity difference is large, so a higher exposure latitude is required;
2 The ability of network reproduction, generally the United States DUPONT version of the continuous network can achieve 1% - 95%, independent network 0.25mm, independent fine line O.175mm;
3 Plate material's own resilience, elasticity and toughness, good elasticity to facilitate pressure adjustment during printing;
4 The dimensional stability and solvent resistance of the plate can increase the plate life.
9Q: What are the common problems in platemaking? (1) The relief is too shallow and the text is unclear. Ultraviolet tube aging, back exposure and main exposure time, vacuum, film and darkness are not enough.
(2) The lines become thicker and the dots are brighter. Vacuum adsorption is not good, it is recommended to use frosted film.
(3) Plate cracks. When making a plate, the time for de-sticking is too long; if it is not properly stored during repetitive printing, black plates or opaque plastic bags should be used to protect the cleaned plate.
(4) The surface of orange peel. The main exposure time is too short and the proportion of the solvent in the plate wash is too high and should be controlled at 1.41.
Frequently asked questions are not the same in different environments, different equipment, and different operating personnel. However, the reasons for this happening are generally associated with the six-part template (back exposure, main exposure, washing, drying, de-bonding, and post-processing). It is related to the operation during printing (pressure effect, influence of ink).
First, for a new plate, back exposure and main exposure must be tested. According to general experience, the thickness of the substrate should be 1/2 of the thickness of the plate. The main exposure time is based on the results of the plate making at different times. The lines and the field take the longest time. The treatment before the main exposure can not be taken lightly, vacuum negative pressure should be 0.8Pa. At present, most plate-making companies use offset printing films, which are not conducive to vacuum suction. We hereby call for everyone to use matte films in order to reduce losses caused by vacuum suction.
The impact of platewashing is even greater, and the machine's brushes require flexibility and smoothness. If the proportion of solvent is too high, orange peel phenomenon will occur, thin lines, network points will be lost, if too low, the version is not easy to clean, the viscosity is not easy to reduce, pattern relief is not deep enough.
For the DUPONT version, its drying requires baking at 60°C for 2 hours. Otherwise, there will be platen edges, uneven thickness, elasticity and hardness cannot be fully recovered, and serious ghosting on the edges of the field will occur during printing. .
The post-treatment detackification was performed under UV-C 10 mW conditions for 5 minutes. The longer the detackification time due to the plate washing time and the solvent concentration, will cause the plate to crack. When printing, due to excessive ethanol or additives exceed the prescribed amount, will cause cracking.
Ensure that the density of the translucent zone of the film is less than 0.08, so as to make the plate material have better light curing, making the pattern more robust, clear, and reaching a certain hardness.
The opacity zone blackness requirement is greater than 4.0 to ensure smooth reproduction of the plate base area and relief pattern. Too low film density will make the embossing height of the plate not enough.
2Q: What is a photopolymerization relief printing plate made of photosensitive resin material by exposure and rinsing.
Solid type: printing plates made of pre-formed photosensitive resin plate, used for mechanical molding, good flatness, molding shrinkage, dimensional stability.
Liquid Curing Type: The printing plate made of liquid photosensitive resin as plate making material has poor dimensional stability, and the layout shrinkage is greatly affected by temperature and humidity.
3Q: What are the requirements for the light source of the flexographic plate?
The light source used is an ultraviolet light source, the wavelength of the UV-A light source is 320-400 nm, and the wavelength of the UV-C light source is 280-320 nm.
4Q: The composition and requirements of the platesetter and UV-A UV exposure system should be selected with Philips UVA-R UV lamps, equipped with high-quality ballasts and starters, and only the main circuit power supply must be connected during exposure. The lamp can be activated instantaneously to achieve even exposure. Light intensity can reach 10-18mW/cm2.
Plate version system, wash brush should be selected soft brush corrosion resistance and toughness, plate washing mode is divided into several types, drum type, inline type, platform type requirements adjust the level of paste table and brush surface Contact, otherwise there will be uneven flushing or embossing phenomenon; drum type: UV polishing using roller type plate, can reduce the size of the resin glazing deformation to a minimum; inline: domestic introduction The state-of-the-art flexo platesetter can set plate thickness, plate wash time, solvent concentration, and can be finally cleaned and pre-baked. The solvent of washing plate is divided into common type and environment-friendly type, the common type solvent is proportioned by tetrachloroethylene and n-butanol, the specific gravity is about 1.41, and the environmental protection solvent is generally imported from U.S. DUPONT.
Drying system, due to solvent plate, plate expansion and deformation, and showing a certain degree of stickiness, so the plate must be placed in a drying drawer at 60 °C temperature and dry for 90 minutes, making the plate back to the thickness of the plate.
Post-processing, using a UV-C light source for de-tacking, the de-tacking time is determined based on the intensity of the light source and the concentration of the solvent, and then the UV-A light source is used for final curing.
5Q: Why use a solvent recovery machine after washing the waste liquid, can be distilled at high temperature and recycled to save the solvent, so that there can be enough fresh solvent to supplement the wash plate, so that the solvent during the process of polishing is kept to an ideal concentration. The maximum boiling point of the recovery machine can be as high as 220° C., the boiling point of the common solvent is 160° C., and the cooling temperature is 90° C. The capacity of 62 L generally takes 5-6 hours to complete. The boiling point of the environmentally friendly solvent is 200°C, and the capacity of 62L can be completed in 4 hours. Since the recovery temperature is much higher than that of ordinary solvents, a vacuum cooling system is needed to speed up the recovery.
6Q: How to make proofing of proofing and offset printing is somewhat more difficult because there are too many variables from platemaking to color reproduction in flexographic printing. The current advanced method of proofing is the use of DuPont's Cromalin proofing system. The system uses special proofing paper and ink.
7Q: What should you pay attention to in the sticker? Clean the plate cylinder and the back of the plate with alcohol so that the double-sided adhesive tape remains well-adhesive.
When pasting, the sticker surface should be affixed to the plate because the curved feature ensures a good and convenient plate without bubbles. At the overlap of the tail end of the tape, cutting is performed.
Choose a brand of good quality adhesive tape such as tesa tape (TESA), according to different graphic lines and dots to choose the density of tape (soft and hard tape), according to the printing gap, sleeve thickness, thickness of the plate to confirm the thickness of the tape. Test its compressibility and recovery, conformability, and stickiness.
The relationship between the plate and the adhesive tape is "hard and soft". A thin and hard plate with a soft gasket foam tape can achieve a very good printing effect.
8Q: How to choose the printing media first according to the print:
1 carton version, thickness 3.94-7mm, hardness 35-42 (Shore A);
2 plastic bag version, thickness 2.28-2.84mm, hardness 50-60 (Shore A);
3 Soft pack and trademark version 1.14-1.70mm, hardness 60-70 (Shore A).
The following points should be noted when selecting the plate material:
1 Exposure latitude in platemaking, because the brand performance of current domestic platesetters cannot be unified, and the light intensity difference is large, so a higher exposure latitude is required;
2 The ability of network reproduction, generally the United States DUPONT version of the continuous network can achieve 1% - 95%, independent network 0.25mm, independent fine line O.175mm;
3 Plate material's own resilience, elasticity and toughness, good elasticity to facilitate pressure adjustment during printing;
4 The dimensional stability and solvent resistance of the plate can increase the plate life.
9Q: What are the common problems in platemaking? (1) The relief is too shallow and the text is unclear. Ultraviolet tube aging, back exposure and main exposure time, vacuum, film and darkness are not enough.
(2) The lines become thicker and the dots are brighter. Vacuum adsorption is not good, it is recommended to use frosted film.
(3) Plate cracks. When making a plate, the time for de-sticking is too long; if it is not properly stored during repetitive printing, black plates or opaque plastic bags should be used to protect the cleaned plate.
(4) The surface of orange peel. The main exposure time is too short and the proportion of the solvent in the plate wash is too high and should be controlled at 1.41.
Frequently asked questions are not the same in different environments, different equipment, and different operating personnel. However, the reasons for this happening are generally associated with the six-part template (back exposure, main exposure, washing, drying, de-bonding, and post-processing). It is related to the operation during printing (pressure effect, influence of ink).
First, for a new plate, back exposure and main exposure must be tested. According to general experience, the thickness of the substrate should be 1/2 of the thickness of the plate. The main exposure time is based on the results of the plate making at different times. The lines and the field take the longest time. The treatment before the main exposure can not be taken lightly, vacuum negative pressure should be 0.8Pa. At present, most plate-making companies use offset printing films, which are not conducive to vacuum suction. We hereby call for everyone to use matte films in order to reduce losses caused by vacuum suction.
The impact of platewashing is even greater, and the machine's brushes require flexibility and smoothness. If the proportion of solvent is too high, orange peel phenomenon will occur, thin lines, network points will be lost, if too low, the version is not easy to clean, the viscosity is not easy to reduce, pattern relief is not deep enough.
For the DUPONT version, its drying requires baking at 60°C for 2 hours. Otherwise, there will be platen edges, uneven thickness, elasticity and hardness cannot be fully recovered, and serious ghosting on the edges of the field will occur during printing. .
The post-treatment detackification was performed under UV-C 10 mW conditions for 5 minutes. The longer the detackification time due to the plate washing time and the solvent concentration, will cause the plate to crack. When printing, due to excessive ethanol or additives exceed the prescribed amount, will cause cracking.
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In addition to them,we also supply the cubing machines.
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