Alignment positioning in screen printing means that each part of a printed pattern is accurately printed in a desired sheet area (or dot) by controlling a Printing Plate for each color. Whether or not the overlay is accurate depends on each step of the entire printing process. To obtain accurate registration, you must carefully complete the work of each step. The following are some of the steps to complete the registration. If you can do these steps carefully, the printer can obtain accurate registration positioning without any problems. The steps are: First, the net should be as tight as possible; second, prepare and affix the printing plate ; third, the printing plate should be placed in the same position of the substrate each time; and the substrate should be placed in the same position each time; If yes, printing should be done at the same temperature (because the substrate or other material may shrink or expand at different temperatures).
In order to obtain accurate register positioning, various technologies and equipments are used in screen printing. For paper, cardboard, and other thin substrates, it is recommended to place one or two wrappers, liners, and book paper under the printing plate. These pads can be glued to the surface with tapes, tapes, and other adhesives. In this way, prepress preparation for proper overprinting is done. When printing a monochrome job, one thing the printer must do is draw a reference line on the offset paper, that is, use a pencil to draw two perpendicular lines under and on one side of the offset paper. In printing, the substrates are to be placed as guides against them.
The register rails can be referenced to the printing machine or referenced to the offset paper. There are usually three rails. In general, the substrate is based on the next register rail plus the left (or right) registration rail.
For thinner substrates, a simple register guide can be used. This guide rail is made of folded tape, plastic tape, and then fastened to the required point of the offset paper or table. A more precise method of achieving a precision of about 1/8 inch (0.31 cm) for leveling the substrate is to cut a V-shaped groove above the offset paper and fold it back in the opposite direction of the substrate to form a registration cover. . If these register caps are made long enough, they will facilitate the removal of the substrate from the printing plate because the registration cap has a tendency to peel off the substrate from the plate.
When the substrate is approximately 1/16 inch (0.16 cm) thick or thicker, iron rails, cardboard rails, or plastic rails are recommended. These guides can be made on their own or they can be purchased from screen printing suppliers. Parts can be cut from angle steel or from T steel. Flat parts can be cut by hinges to create the ideal guide rails because they already have drilled holes. Figure 39 shows a common simple guide rail that can be fixed to the table with two small screws (usually tack). After the guide rail is in the designated position, tighten the screw.
Most commercial rails are about 1/16 inch (0.16 cm) thick or thicker. To print thin substrates, you must use cardboard for the screen base and leave a slot in the base for the rails. The top of the rail should be level with or lower than the surface of the printing substrate. In addition, the guide rails should have no sharp points and do not damage the screen. It is also necessary to prevent the guide rail from rubbing the screen. It is recommended to stick tape to the part where the screen contacts the guide rail. When printing on other materials mentioned later, screens and printing plates should also be protected to prevent damage.
When printing on a thicker substrate, the screen plate must be adjusted so that its spacing from the table is comparable to the thickness of the substrate. There is also a method for changing the distance between the screen plate and the table surface by inserting a spring between the hinge bar (or screen) and the table surface. By tightening the nut on the top of the hinge, a spacing suitable for the thickness of the substrate can be obtained. If there is no spring, it can be cut, drilled, and then placed in the middle of the hinge rod and table with the same material and the same thickness as the substrate. Of course, the front of the screen should also be mated to the same height to prevent the front of the screen plate from being too low. This can be achieved by tightening the front pad.
Sometimes it is necessary to print difficult-to-register materials such as silk and irregularly shaped materials, such as silk fabrics, sweatshirts, etc. These substrates cannot insert a solid material as a pad, and sometimes print several colors. It is also necessary to attach a clear plastic sheet or drawing sheet to the Table Top. In operation, first print the pattern to be printed on the paper, and then place the substrate on the transparent paper under proper position with the printed pattern as a reference; position the transparent paper to fold it up and print the desired pattern on the substrate. This pattern can be accurately registered.
The side splint is very easy to load on the printing device and is also easy to remove. This method is often used for registering when there are many print runs. This method can eliminate uneven prints and side gaps caused by loose hinges or other reasons. The side splint registration method keeps the screen plate in the correct position on the table each time. Eliminate the effect of the screen plate being too low or moving under the pressure of the squeegee. Another way to eliminate the side gap is to load a 3/8 inch (0.95 cm) alignment pin on the edge of the lower screen frame on the screen plate. A hole of the same size as the locating pin is drilled on the tabletop for use when the screen plate is too low, the locating pin may also be in the hole in the table.
When printing on glass or other smooth materials, it is necessary to maintain the off-gauge gap between the screen plate and the printing plate, and the contact between the plate and the substrate occurs only when the squeegee blade presses. If you want to maintain a certain gap, you can stick enough tape under the frame.
For multi-color printing, accurate registration positioning is required, especially when image duplication is performed in halftone. In the case of multicolor printing, slight deviations in one of the plates will damage the final result of the printing. This printing type is easier to control with mechanical operation than manual operation. Because the machine has automatic adjustment function.
It is worth noting that it is necessary to conduct a careful inspection of each color before starting printing. To check the size of the image and the colors that have been printed, check that each Color Plate is able to register. The inspection method may be a method of proofing on transparent paper. Then check whether each color plate can register with light or windows. Only the proofs are registered, and the printed registration is guaranteed.
In order to obtain accurate register positioning, various technologies and equipments are used in screen printing. For paper, cardboard, and other thin substrates, it is recommended to place one or two wrappers, liners, and book paper under the printing plate. These pads can be glued to the surface with tapes, tapes, and other adhesives. In this way, prepress preparation for proper overprinting is done. When printing a monochrome job, one thing the printer must do is draw a reference line on the offset paper, that is, use a pencil to draw two perpendicular lines under and on one side of the offset paper. In printing, the substrates are to be placed as guides against them.
The register rails can be referenced to the printing machine or referenced to the offset paper. There are usually three rails. In general, the substrate is based on the next register rail plus the left (or right) registration rail.
For thinner substrates, a simple register guide can be used. This guide rail is made of folded tape, plastic tape, and then fastened to the required point of the offset paper or table. A more precise method of achieving a precision of about 1/8 inch (0.31 cm) for leveling the substrate is to cut a V-shaped groove above the offset paper and fold it back in the opposite direction of the substrate to form a registration cover. . If these register caps are made long enough, they will facilitate the removal of the substrate from the printing plate because the registration cap has a tendency to peel off the substrate from the plate.
When the substrate is approximately 1/16 inch (0.16 cm) thick or thicker, iron rails, cardboard rails, or plastic rails are recommended. These guides can be made on their own or they can be purchased from screen printing suppliers. Parts can be cut from angle steel or from T steel. Flat parts can be cut by hinges to create the ideal guide rails because they already have drilled holes. Figure 39 shows a common simple guide rail that can be fixed to the table with two small screws (usually tack). After the guide rail is in the designated position, tighten the screw.
Most commercial rails are about 1/16 inch (0.16 cm) thick or thicker. To print thin substrates, you must use cardboard for the screen base and leave a slot in the base for the rails. The top of the rail should be level with or lower than the surface of the printing substrate. In addition, the guide rails should have no sharp points and do not damage the screen. It is also necessary to prevent the guide rail from rubbing the screen. It is recommended to stick tape to the part where the screen contacts the guide rail. When printing on other materials mentioned later, screens and printing plates should also be protected to prevent damage.
When printing on a thicker substrate, the screen plate must be adjusted so that its spacing from the table is comparable to the thickness of the substrate. There is also a method for changing the distance between the screen plate and the table surface by inserting a spring between the hinge bar (or screen) and the table surface. By tightening the nut on the top of the hinge, a spacing suitable for the thickness of the substrate can be obtained. If there is no spring, it can be cut, drilled, and then placed in the middle of the hinge rod and table with the same material and the same thickness as the substrate. Of course, the front of the screen should also be mated to the same height to prevent the front of the screen plate from being too low. This can be achieved by tightening the front pad.
Sometimes it is necessary to print difficult-to-register materials such as silk and irregularly shaped materials, such as silk fabrics, sweatshirts, etc. These substrates cannot insert a solid material as a pad, and sometimes print several colors. It is also necessary to attach a clear plastic sheet or drawing sheet to the Table Top. In operation, first print the pattern to be printed on the paper, and then place the substrate on the transparent paper under proper position with the printed pattern as a reference; position the transparent paper to fold it up and print the desired pattern on the substrate. This pattern can be accurately registered.
The side splint is very easy to load on the printing device and is also easy to remove. This method is often used for registering when there are many print runs. This method can eliminate uneven prints and side gaps caused by loose hinges or other reasons. The side splint registration method keeps the screen plate in the correct position on the table each time. Eliminate the effect of the screen plate being too low or moving under the pressure of the squeegee. Another way to eliminate the side gap is to load a 3/8 inch (0.95 cm) alignment pin on the edge of the lower screen frame on the screen plate. A hole of the same size as the locating pin is drilled on the tabletop for use when the screen plate is too low, the locating pin may also be in the hole in the table.
When printing on glass or other smooth materials, it is necessary to maintain the off-gauge gap between the screen plate and the printing plate, and the contact between the plate and the substrate occurs only when the squeegee blade presses. If you want to maintain a certain gap, you can stick enough tape under the frame.
For multi-color printing, accurate registration positioning is required, especially when image duplication is performed in halftone. In the case of multicolor printing, slight deviations in one of the plates will damage the final result of the printing. This printing type is easier to control with mechanical operation than manual operation. Because the machine has automatic adjustment function.
It is worth noting that it is necessary to conduct a careful inspection of each color before starting printing. To check the size of the image and the colors that have been printed, check that each Color Plate is able to register. The inspection method may be a method of proofing on transparent paper. Then check whether each color plate can register with light or windows. Only the proofs are registered, and the printed registration is guaranteed.
Haoxin Ceramics Industrial Co., Ltd. , http://www.czhxceramics.com