At present, gravure plate making mainly includes: direct etching gravure, electronic engraving gravure, laser engraving gravure, electron beam engraving gravure, etc.
Direct etching gravure is a process of drying gravure grid on carbon paper sensitized by dichromate, and then drying the continuous positive adjustment map. Then the image on the carbon paper is transferred to the roller, and the plate is made by developing, filling and etching. Direct etching gravure is mainly controlled by manual work, so the stability of plate making, the uniformity of field density, the repeatability of reprint and the clarity of characters are poor. It is generally only used for ordinary plastic flexible packaging printing.
Electronic engraving gravure is to use electronic engraving machine to carve gravure cylinder directly. It is through the scanning head to scan the original, get the density light signal, after photoelectric conversion into electrical signal, after a series of processing by the electronic computer, it is transmitted to the output end, driving the electronic engraving head to carve on the copper drum, and make gravure printing plate.
Laser engraving gravure uses laser engraving machine to carve gravure cylinder, while electron beam engraving gravure uses electron beam gravure engraving machine to carve gravure cylinder.
According to the depth of the original, the scanning head of the Gravure Engraving machine converts it into electrical signals of different sizes one by one. Through the different vibration strength of the diamond engraving needle, the depth and depth of the dots are engraved on the surface of the cylinder, corresponding to the bright part of the original, the mesh point is shallow and small, and corresponding to the dark part of the original, the dot is deep and large. Because the level reproduction of image is achieved by the change of dot size and depth, electronic engraving gravure can truly reflect the original level. Its plate making stability, field density uniformity, reprint repeatability is excellent, printed text is very clear.
The cost of laser engraving gravure and electron beam engraving gravure is too high. Although the two methods of engraving the plate quality is very high. But at present, it is still used less, most gravure is still mainly electronic engraving.
In order to ensure the quality of electronic engraving gravure, the size and depth of engraving mesh are specified in the industry standard. However, the size and depth of the mesh hole are affected by the machine type (products of different companies), the number of mesh wires, the old and new degree of the cutter, the angle of the cutter, the thickness of the copper layer (the hardness of the copper layer is 180-210 Vickers) and the product quality requirements. In the industry standard, only 70 line / cm, 130 ° angle of cutter and new cutter are taken as examples.
(manufacturer of antistatic aluminum foil bag, fruit bag, daily chemical packaging bag, packaging roll film manufacturer of Beite (China) packaging Co., Ltd.)