How to distinguish the paste plate and drag bad in gravure printing
Gravure printing often encounter paste plate and drag bad failure, these two failures show the phenomenon, the causes and solutions are different, but there are many people, including some articles published in professional printing magazines, these two failures are mixed up, so it is easy to mislead people who just contact gravure printing. 1. show the phenomenon of different drag bad from a certain part of the image began to appear gradual, gradually disappear, the shape like The animal, often referred to as trailing. The paste version is different, it is in the edge of the text overflow and the width of the text is basically the same, the ink color is lighter than the text, the shape of the indeterminate graphics. 2. different reasons for the generation of dragging bad cause is the squeegee
Gravure printing often encounter paste plate and drag bad failure, these two failures show the phenomenon, the causes and solutions are not the same, but there are many people, including some articles published in professional printing magazines, these two failures are mixed together, so it is easy to mislead people who just contact gravure printing.
1. Showing different phenomena
Dragging bad is a gradual change from a certain part of the graphic, gradually disappear, the shape of the animal, often called dragging tail.
The paste version is different, it is in the edge of the text overflow and the width of the text is basically the same, the ink color is lighter than the text, the shape of the variable graphics.
2. Different reasons for generation
The reason for the production of bad drag is impurities between the scraper and the printing plate, and extended to the back of the ground knife. Scraper scrape through the printing plate on the graphic part, impurities and ink contact, scraper scrape out force production text part, impurities behind the blade, contact with the printing plate, the graphic drag bad.
The paste version is mainly due to the scraper and the printing plate into an arc contact, that is to say, the knife is very tight, air pressure is also large, scraper scraping through the graphic part of the printing plate, a long time under pressure of the blade has the tendency to straighten, which is allowed in the elastic range. When the squeegee moved out of the graphic part, the blade touches the shoulder of the network, it will be like a ball hitting the wall rebound, so the blade in moving out of the graphic part of the printing plate, and the graphic contact of that part of the squeegee will be sideways to let, can not scrape the plate clean, under the action of printing pressure, the ink will spill out of the graphic part, resulting in paste plate.
3. Different solutions
Production encountered in the graphics drag bad fault, generally just use bamboo chopsticks gently scraped on it.
When encountering the problem of paste plate, it is necessary to solve by loosening the knife and reducing the air pressure.
4. Common points of the two kinds of failure
Ink viscosity is relatively low, dragging bad and paste plate failure are prone to occur, therefore, appropriate to improve the ink viscosity to eliminate the occurrence of the above two failures have a great role.
Rotary printing press to die-cutting machine
Printing plant in a rotary blitz printing machine can be converted into a die-cutting machine, converted into a die-cutting machine overprint accurate, uniform pressure, die-cutting speed, simple operation, low labor intensity, can be used for die-cutting 450g / m square below the printed parts. The machine can also be used to press the concave protrusion, also has the advantages of accurate overprinting, high pressure, fast speed, etc..
Specific modification steps are as follows:
First, the ink hopper assembly will be removed as a whole. To ensure the safety of the use of modified equipment, another machine can make a glass shield, cover the plate table. The shield should be designed to open the form, in order to facilitate the operation of loading plates.
Then, the embossing cylinder lining removed, with a thickness of about 0.50 mm stainless steel skin wrapped. According to the different thickness of the printed parts, the steel skin can be lined with PS plate, polyester sheet base or paper, to ensure that the thickness of the printed parts themselves plus the total thickness of the impression cylinder liner does not exceed 1.20mm.
Then, the die-cutting plate is installed, and a round and flat die-cutting machine is successfully modified.
Indentation and forming quality of corrugated boxes
In the production of corrugated cartons, except for some cartons with high requirements for forming quality, which have to be put on high-speed automatic packaging lines, the process route is basically to slit, crease, open bad and open corners, form and nail boxes. Among them, creasing plays a key role in the quality of corrugated boxes.
The role of creasing is to enable corrugated cardboard to be folded into boxes according to design requirements. The structure of corrugated cardboard is different from that of ordinary cardboard. Therefore, in order to ensure that the creasing line is clear and does not damage the cardboard, that it is easy to fold and shape, that the corners are well-defined after folding, and that the flute line is straight and the box is straight, great care is taken in the arrangement of the creasing knife line and in the selection of the creasing knife line. Especially for thicker corrugated board, the quality of the indentation, the size of the box and the position of the indentation have a lot to do with each other.
For longitudinal creasing, when the creasing line falls at the peak or valley of the corrugated core, the quality of the creasing is generally better and the size of the box can be easily guaranteed. However, if the indentation line falls between the flute peak and the flute valley, that is, at the half-waist, it is difficult to guarantee the quality of the indentation, and the forming size of the carton will often be deviated.