Different printing mechanisms
In flexographic printing, the ink is transferred to the printing plate by an anilox roller and then transferred to the printing substrate, while the gravure printing is directly inked by the plate cylinder and then transferred to the printing substrate. Therefore, the amount of ink used for flexo printing is determined by the anilox roller, and the amount of ink applied to the gravure is determined by the printing plate.
Due to the limitations of the processing technology, the number of anilox roller lines cannot reach a particularly high level before, so the flexographic printing dots are larger and the cable lines are slightly thicker, which is still not comparable to gravure printing. At the same time, since the depth and density of the cell depth are the same in each section of the anilox roller, for the dark colored screen version, the solid part and the hanging part must be separated, otherwise it can only be false in the field and the color is light. Or dirty spots often appear on the part of the net, and the printing effect cannot be taken into account at both the field and the net.
Gravure printing has relatively few limitations in this regard, but for a large area of ​​small-scale dot-dot dark screens, the field part and the hanging part should also be separated, otherwise the hanging part is prone to pitting, which is also difficult to control. . Therefore, relative to offset printing, relative to offset printing, there may be an increase in the number of printing plates regardless of flexo printing or gravure printing, and it cannot simply be said that there are fewer gravure printing plates, and flexographic printing must increase the number of printing plates. The number of color plates depends on the original image, but also depends on the customer's requirements, the degree of acceptance, and the printer's technical level and equipment level.
Different ease of operation
The common faults of flexo printing are relatively few. The main faults are white dots in the field, dirty dots on the network cable, and the occurrence of other faults is relatively small. Therefore, in general, flexo printing is a more economical printing process.
The gravure printing has more random failures, mainly including knife-line dragging, water-blocking patterns, and zebra pattern. The operation is relatively complicated, so the reject rate is relatively high.
However, the gravure printing machine has a short ink path and is highly hand-operable, so the change time is relatively short. Flexo printing requires a security version before printing, and requires a mechanical hanging plate, plus ink path length, so the change time is relatively long, but for larger orders, because the probability of failure is greatly reduced, so the completion of the order The time is relatively short and the yield is high.
Substrate substrate is different
In plastic flexible packaging printing, there are many films that can be used as substrates.
Gravure machine can print PE, CPP, 0PP, PET, 0N and other films.
Flexo printing machine can print PE, CPP, 0PP and other films.
In particular, for the stretch material PE, the gravure can only print materials that are relatively thick and have more low-pressure material. Flexo printing, on the other hand, can be used to print materials of various thicknesses and proportions. This is mainly due to the different printing mechanism of the two: the gravure printing adopts the unit type printing method, which will result in inconsistent deformation rate of the printing material after passing through the drying box and multiple guide rollers, resulting in overprint deviation: the use of satellites for flexographic printing machines Arrangement, there is only one impression cylinder, the deformation rate of printing materials in each color group is the same, so the overlay accuracy is high.
When different packaging users select printers, in addition to examining the manufacturer's equipment and technical capabilities, they should also consider the substrates they have selected, and choose the right ones to obtain satisfactory prints.
Different contributions to environmental protection
Flexographic inks are alcohol inks, and gravure inks are mostly benzene inks. Flexo printing in this area has unparalleled advantages. Although in recent years, gravure inks have also tried alcoholic inks, the effect is not particularly satisfactory, and inks suitable for printing ON and PET must be benzene inks. Therefore, in a short period of time, it is not realistic for gravure to completely reform. In short, in the field of flexible packaging printing, there are different markets for gravure printing and flexo printing. If appropriate choices can be made, it is not difficult to obtain satisfactory print products. The key is that the packaging users must have their own characteristics of the two printing methods. Have some understanding, do not blindly pursue something that cannot be achieved, and do not mention the requirements of super-standards. Whether it is a printer or a packaging user, the pursuit of satisfactory packaging is the ultimate goal.
The advantages and disadvantages of gravure printing and flexo printing
An important advantage of the flexographic printing system is that the contact between the printing plate and the tape is only in the convex area, which allows the second color to be printed on it when the first color is half dry, and does not require a gravure printing. As in the machine, the ink must dry completely between the two color groups. Flexo printing allows a certain degree of "wet-on-wetting" printing. The drying length can be as short as a few centimeters, so that the 8-10 color printing group can be distributed around a large center roll. This large drum becomes a common impression cylinder for all printing groups, thus ensuring the necessary rigidity for accurate overprinting and printing of extensible films.
In gravure printing, there must be a certain line pressure on the engraving drum, and the material belt is mechanically tensioned. The ink must be completely dry before it enters the next printing group. Each printing color group must be completely dry. The length of the color group is larger than that of the color group. From the perspective of energy saving, this process has a higher cost.
This, in turn, leads to an increased difficulty in the protection of registration accuracy, and thus requires the installation of an electromechanical electromechanical adjustment device (registration control device). Another issue relates to the processing of printing plates. The gravure cylinder is expensive, but at the same time it is very strong, can be used for long-lived, can be reused without change in the value of the adjustment. On the other hand, a flexo-printed plate is easily mounted on or removed from the cylinder, and its dimensions can be made the same as the area of ​​an effective printed graphic. For small prints, small plates can be irrelevant to the size of the rollers. In gravure printing, however, the entire drum needs to be prepared both in width and in the circumferential direction (the current electromechanical system reduces this advantage: the small printing surface requires less engraving time). It has often been seen before that the flexo never had the fourth decimal point accurate. However, due to technological advancement, significant advances have now been made in obtaining infinitely variable repetition lengths. However, it is still not as significant as the gravure progress.
In flexographic printing, the contact pressure of the ink roller with the plate, and the contact pressure between the platen and the tape must be at a minimum. This means that the equipment must be operated very accurately. The adjustment device must have a fine-tuning mechanism. The central roller of a 6-color machine should allow an eccentricity of 8,000 to 10,000 millimetres. The difference in thickness must be less than two-tenths of a millimeter, and the runout of 3 to 5 dry cents per minute between the ink roller and the printing plate will impair the printing quality.
In the past, people always believed that flexographic printing would never reach the level of fine text that could be expressed satisfactorily, such as Japanese and Chinese texts. However, with the adoption of ultra-fine mesh and laser technology, flexo printing has entered the past and has been Think of it as a gravure market. Thanks to the brand-new design of the press manufacturer, gravure printing in parts of the United States, Europe and Southeast Asia regained its vast territory. They have effectively changed the status of the industry, giving them the following advantages over flexo printing:
If an 8-color (central impression cylinder) Cl-type printer is used, it takes at least one and a half hours to change the printing plate, match colors, and re-enter production conditions, while a single 8-color intaglio printing press requires only 30 Minutes, including cleaning, adjustment, color matching, and registration.
Another major advantage of gravure printing is its ability to handle 2.5 micron PE films, lightweight materials such as 5 micron aluminum foil, up to 46 mil plastisols, light tin plates, thick aluminum foil and major industrial products. In addition, the use of extended dryer, which can be cold and heat sealing, hot melt wax, wire cutting, flat pressure and round pressure wire molding, wire cutting and indentation and wiring compound.
Comparing the above gravure printing and flexographic printing systems, the following points can be summarized:
1. Printing quality: In general, gravure printing is preferred.
2. Control registration: Flexo printing is easier when no control device is used.
3. The cost of the printing plate: Comparing the same printing areas, the costs are comparable.
4. Printing plate storage: It is easy to deal with flexo plates. It can be removed from the plate cylinder and laid flat for later use. The intaglio cylinder needs a lot of space and expensive transportation equipment.
5. Plate life: The gravure metal roller has a long life.
6. Ink: The size and depth of the ink hole are variable, which undoubtedly provides better halftone control for gravure printing.
7. Structure: Many types of solvents and resins can be used for gravure printing. The rollers that come in contact with the ink and glossy oil are not damaged, and the rubber and photosensitive resin are damaged.
8. Repeated text length: In flexographic printing, the repeat length is limited by the size of the gear teeth.
9. Maximum number of prints: In flexographic printing, the maximum number of prints is 8 colors. In gravure printing, 10 to 12 color groups can be arranged. If you leave enough room in advance, you can expand the color group even after installation.
1O. Drying: In flexographic printing, a simple-structured drying system sometimes limits the speed of printing. In gravure printing, the dryer of each color group can be sized based on speed, solvent solids, and the like.
Source: Export Goods Packaging
In flexographic printing, the ink is transferred to the printing plate by an anilox roller and then transferred to the printing substrate, while the gravure printing is directly inked by the plate cylinder and then transferred to the printing substrate. Therefore, the amount of ink used for flexo printing is determined by the anilox roller, and the amount of ink applied to the gravure is determined by the printing plate.
Due to the limitations of the processing technology, the number of anilox roller lines cannot reach a particularly high level before, so the flexographic printing dots are larger and the cable lines are slightly thicker, which is still not comparable to gravure printing. At the same time, since the depth and density of the cell depth are the same in each section of the anilox roller, for the dark colored screen version, the solid part and the hanging part must be separated, otherwise it can only be false in the field and the color is light. Or dirty spots often appear on the part of the net, and the printing effect cannot be taken into account at both the field and the net.
Gravure printing has relatively few limitations in this regard, but for a large area of ​​small-scale dot-dot dark screens, the field part and the hanging part should also be separated, otherwise the hanging part is prone to pitting, which is also difficult to control. . Therefore, relative to offset printing, relative to offset printing, there may be an increase in the number of printing plates regardless of flexo printing or gravure printing, and it cannot simply be said that there are fewer gravure printing plates, and flexographic printing must increase the number of printing plates. The number of color plates depends on the original image, but also depends on the customer's requirements, the degree of acceptance, and the printer's technical level and equipment level.
Different ease of operation
The common faults of flexo printing are relatively few. The main faults are white dots in the field, dirty dots on the network cable, and the occurrence of other faults is relatively small. Therefore, in general, flexo printing is a more economical printing process.
The gravure printing has more random failures, mainly including knife-line dragging, water-blocking patterns, and zebra pattern. The operation is relatively complicated, so the reject rate is relatively high.
However, the gravure printing machine has a short ink path and is highly hand-operable, so the change time is relatively short. Flexo printing requires a security version before printing, and requires a mechanical hanging plate, plus ink path length, so the change time is relatively long, but for larger orders, because the probability of failure is greatly reduced, so the completion of the order The time is relatively short and the yield is high.
Substrate substrate is different
In plastic flexible packaging printing, there are many films that can be used as substrates.
Gravure machine can print PE, CPP, 0PP, PET, 0N and other films.
Flexo printing machine can print PE, CPP, 0PP and other films.
In particular, for the stretch material PE, the gravure can only print materials that are relatively thick and have more low-pressure material. Flexo printing, on the other hand, can be used to print materials of various thicknesses and proportions. This is mainly due to the different printing mechanism of the two: the gravure printing adopts the unit type printing method, which will result in inconsistent deformation rate of the printing material after passing through the drying box and multiple guide rollers, resulting in overprint deviation: the use of satellites for flexographic printing machines Arrangement, there is only one impression cylinder, the deformation rate of printing materials in each color group is the same, so the overlay accuracy is high.
When different packaging users select printers, in addition to examining the manufacturer's equipment and technical capabilities, they should also consider the substrates they have selected, and choose the right ones to obtain satisfactory prints.
Different contributions to environmental protection
Flexographic inks are alcohol inks, and gravure inks are mostly benzene inks. Flexo printing in this area has unparalleled advantages. Although in recent years, gravure inks have also tried alcoholic inks, the effect is not particularly satisfactory, and inks suitable for printing ON and PET must be benzene inks. Therefore, in a short period of time, it is not realistic for gravure to completely reform. In short, in the field of flexible packaging printing, there are different markets for gravure printing and flexo printing. If appropriate choices can be made, it is not difficult to obtain satisfactory print products. The key is that the packaging users must have their own characteristics of the two printing methods. Have some understanding, do not blindly pursue something that cannot be achieved, and do not mention the requirements of super-standards. Whether it is a printer or a packaging user, the pursuit of satisfactory packaging is the ultimate goal.
The advantages and disadvantages of gravure printing and flexo printing
An important advantage of the flexographic printing system is that the contact between the printing plate and the tape is only in the convex area, which allows the second color to be printed on it when the first color is half dry, and does not require a gravure printing. As in the machine, the ink must dry completely between the two color groups. Flexo printing allows a certain degree of "wet-on-wetting" printing. The drying length can be as short as a few centimeters, so that the 8-10 color printing group can be distributed around a large center roll. This large drum becomes a common impression cylinder for all printing groups, thus ensuring the necessary rigidity for accurate overprinting and printing of extensible films.
In gravure printing, there must be a certain line pressure on the engraving drum, and the material belt is mechanically tensioned. The ink must be completely dry before it enters the next printing group. Each printing color group must be completely dry. The length of the color group is larger than that of the color group. From the perspective of energy saving, this process has a higher cost.
This, in turn, leads to an increased difficulty in the protection of registration accuracy, and thus requires the installation of an electromechanical electromechanical adjustment device (registration control device). Another issue relates to the processing of printing plates. The gravure cylinder is expensive, but at the same time it is very strong, can be used for long-lived, can be reused without change in the value of the adjustment. On the other hand, a flexo-printed plate is easily mounted on or removed from the cylinder, and its dimensions can be made the same as the area of ​​an effective printed graphic. For small prints, small plates can be irrelevant to the size of the rollers. In gravure printing, however, the entire drum needs to be prepared both in width and in the circumferential direction (the current electromechanical system reduces this advantage: the small printing surface requires less engraving time). It has often been seen before that the flexo never had the fourth decimal point accurate. However, due to technological advancement, significant advances have now been made in obtaining infinitely variable repetition lengths. However, it is still not as significant as the gravure progress.
In flexographic printing, the contact pressure of the ink roller with the plate, and the contact pressure between the platen and the tape must be at a minimum. This means that the equipment must be operated very accurately. The adjustment device must have a fine-tuning mechanism. The central roller of a 6-color machine should allow an eccentricity of 8,000 to 10,000 millimetres. The difference in thickness must be less than two-tenths of a millimeter, and the runout of 3 to 5 dry cents per minute between the ink roller and the printing plate will impair the printing quality.
In the past, people always believed that flexographic printing would never reach the level of fine text that could be expressed satisfactorily, such as Japanese and Chinese texts. However, with the adoption of ultra-fine mesh and laser technology, flexo printing has entered the past and has been Think of it as a gravure market. Thanks to the brand-new design of the press manufacturer, gravure printing in parts of the United States, Europe and Southeast Asia regained its vast territory. They have effectively changed the status of the industry, giving them the following advantages over flexo printing:
If an 8-color (central impression cylinder) Cl-type printer is used, it takes at least one and a half hours to change the printing plate, match colors, and re-enter production conditions, while a single 8-color intaglio printing press requires only 30 Minutes, including cleaning, adjustment, color matching, and registration.
Another major advantage of gravure printing is its ability to handle 2.5 micron PE films, lightweight materials such as 5 micron aluminum foil, up to 46 mil plastisols, light tin plates, thick aluminum foil and major industrial products. In addition, the use of extended dryer, which can be cold and heat sealing, hot melt wax, wire cutting, flat pressure and round pressure wire molding, wire cutting and indentation and wiring compound.
Comparing the above gravure printing and flexographic printing systems, the following points can be summarized:
1. Printing quality: In general, gravure printing is preferred.
2. Control registration: Flexo printing is easier when no control device is used.
3. The cost of the printing plate: Comparing the same printing areas, the costs are comparable.
4. Printing plate storage: It is easy to deal with flexo plates. It can be removed from the plate cylinder and laid flat for later use. The intaglio cylinder needs a lot of space and expensive transportation equipment.
5. Plate life: The gravure metal roller has a long life.
6. Ink: The size and depth of the ink hole are variable, which undoubtedly provides better halftone control for gravure printing.
7. Structure: Many types of solvents and resins can be used for gravure printing. The rollers that come in contact with the ink and glossy oil are not damaged, and the rubber and photosensitive resin are damaged.
8. Repeated text length: In flexographic printing, the repeat length is limited by the size of the gear teeth.
9. Maximum number of prints: In flexographic printing, the maximum number of prints is 8 colors. In gravure printing, 10 to 12 color groups can be arranged. If you leave enough room in advance, you can expand the color group even after installation.
1O. Drying: In flexographic printing, a simple-structured drying system sometimes limits the speed of printing. In gravure printing, the dryer of each color group can be sized based on speed, solvent solids, and the like.
Source: Export Goods Packaging
Mexican Dinnerware,Restaurant Dinnerware,Exclusive Dinnerware
Guangyang Porcelain Art Factory , http://www.gddinnerset.com