The polishing machine performance characteristics and purchase acceptance

The polishing machine is an important equipment for surface finishing of packaging products such as cartons and cartons. It plays a very important role in improving the surface properties of printed products, improving the wear resistance, stain resistance and water resistance of printed products. . For printing and carton enterprises, choosing a polishing machine with excellent structure, stable performance, convenient operation, high production efficiency and wide applicability, and good energy saving, is of great significance to the scientific and rational organization of production. Therefore, correctly understanding and understanding the structure and characteristics of polishing equipment and mastering the procurement control essentials of the polishing machine are an important part of improving production efficiency and product quality.

1 Type of coating machine

The glazing machine is divided into three types: printing machine on-line glazing unit, special glazing machine and printing machine structure. Among them, the multi-color printing machine inline coating machine, the structure has 4 colors, 5 colors, 6 colors plus 1 color or 2 color glazing unit, which can use water or local UV coating, but also can be oil type and solvent Type of glazing; both high-brightness coatings and matt (matte) coatings, as well as drying equipment, high production efficiency, stable quality, showing a good production advantages of multi-color printing presses, improve The market competitiveness of color prints. The common coating machine has a simple structure, convenient operation, and low equipment investment. It is a common coating machine for coating and printing, and has wide product adaptability. It is a device suitable for large, medium and small printing and carton factories. The special glazing machine is divided into two types: manual feeding and automatic feeding. Some of them can not only coat the entire area but also can be used for partial glazing. Reasonable choices should be made according to the actual production conditions of the factory to increase production efficiency. In addition, the use of printing machines can also be partial or full-width glazing, the principle of which is used to receive bright oil or bright light using the printing plate, through the mechanical imprinting of the layout of the bright oil or bright light transfer to the surface of the print.

2 coating structure and characteristics

The glazing structure is divided into an anilox roller scraper type structure, a three-roll direct coating type structure, a scraper roller coating structure, an immersion reverse coating type structure, a cavity type scraper structure, a trailing knife coating structure, and an air knife coating structure. And blade coating structure and so on. Due to the different machine structures, the production efficiency and the quality of the coating are also different.

1) Anilox roller scraper structure

The anilox roller scraper type structure is similar to the flexographic printing machine, and its structure has two rollers, three rollers and four rollers. Among them, three-roll coating is to add a rubber coating roller between the anilox roller and the backing roller. It is required that the viscosity of the coating coating should be appropriately lower, which can facilitate uniform coating. Therefore, it is better than the two roller type. The coating quality of the machine is good. In addition, four-roller machines have great adaptability to coating viscosity and fluidity, and have more uniform coating and good quality. Because the anilox roller is transferred to the light coating by a regular cell, the transfer amount of the coating is almost constant, and the coating coating obtained on the surface of the printing article is relatively uniform and stable. However, if you want to change the thickness of the coating, you should change the different specifications of the anilox roller.

2) Three-roll direct coating structure

The structure consists of a metering roller, a discharge pipe, a coating roller, a doctor blade and a backing roller. The coating amount of the printing product is determined by the gap between the metering roller and the coating roller, and the adjustment is convenient. The three-roll coating structure is simple and can be coated on both sides. For double-sided coating, coating is performed by feeding from the lower chute and the upper conveyor. The structure machine has high production efficiency and less consumption of printed sheets, which is a common coating method.

3) Scraper roller coating structure

The roll-squeegee structure of the coating roller can be the same as or opposite to the direction of sheet feeding, and its speed can also be adjusted to meet the coating requirements. Scraping roller coating is the simplest type of glazing method. The coating roller coats the excess coating on the paper when it is applied, and then the scraping roller scrapes the excess coating to keep the paper surface in the desired condition. Coating, and get a uniform coating quality effect.

4) Immersion reverse coating structure

This machine is generally composed of storage tanks, feeding rolls, leveling rolls, coating rolls, and backing rolls. The gap between the rollers coated by the reverse roller of this type of machine has a greater influence on the quality of the coating coating, and the gap size can be flexibly and conveniently adjusted. In addition, the use of automatic circulation on-machine coatings can help ensure the quality of the printed product.

5) Chamber scraper structure

The structure is measured by the anilox roller polishing oil, two blades on the anilox roller to form a closed cavity, and due to the short cycle of the structure of the oil, coating oil can be reduced volatility, the structure of the light quality The effect is good, it is relatively easy to clean, it is a kind of advanced glazing structure.

6) Drag blade coating structure

When the light is on the structure, the printed sheet is closely attached to the surface of the rubber layer of the backing roller. When the backing roller is rotated through the polishing trough, under the action of the edge of the dragging blade, the surface of the printed sheet can obtain a uniform coating. Drag coater coating structure can also be used for double-sided coating, and is more suitable for high-speed coating. The coating has high concentration, smooth coating, and good coating quality.

7) Air knife coating structure

It is the coating roller to apply the coating material on the surface of the printed sheet. When the printed sheet passes between the backing roller and the air knife, the gas flow is injected from the air knife to form an angle with the printed surface, and the surface of the printed sheet is coated with an excessive amount of coating oil. Blow it into the recovery tank to make the surface of the printed sheet even. The amount of coating applied by the air knife depends on its position with the print sheet, the feed speed, and the viscosity of the coating material. The coating oil applied to the paper surface of the coating roller should be kept to a minimum, and a good glazing effect can be obtained. Air knife coating can obtain a flat and smooth coating on the uneven base paper, and has good adaptability to the original paper glossiness, coating oil concentration and viscosity. However, if a solvent-based coating is used for coating, the organic solvent in the coating will easily contaminate the production environment and increase the loss of the coating due to the gas flow on the air knife. Therefore, the structure is only suitable for the use of water-soluble coatings. Glazing coating.

8) blade coating structure

Squeegee coating is the use of a scraper to scrape the excess paint on the surface of the sheet (after coating the tank) on the backing roller to form a uniform and moderate coating on the paper surface. This coating structure has the problem that the control precision of the coating amount is not high, the coating is prone to streaks, and is generally suitable only for low speed coating production.

3 Structure and characteristics of printing machine on-line coating machine

There are two kinds of structure of on-line glazing of the printing machine, one is that the glazing unit and the mechanism of the printing machine are the same, use the fountain solution system to apply the coating with roller coating; the second is the use of anilox roller and scraper structure, The thickness of the coating coating is controlled by anilox rollers and doctor blades. Multi-color printing presses that cooperate with two coating units are usually coated with roller coating and then coated with an anilox roller. The use of printing machines for on-line glazing has the advantages of high speed, high production efficiency and low production cost, which can reduce the intermediate production links and the loss of printed products, and can better improve the quality of products and increase economic efficiency. The use of printing machine on-line coating can not only polish the entire print, but also polish the local layout of the print. The on-line coating unit can be produced with both on-line offset production and gravure and flexo printing machines for instant printing and glazing. However, the aircraft equipment investment is relatively high, suitable for large and medium-sized factories for high-end, bulk product printing and polishing.

1) Structure and characteristics of ordinary polishing equipment

The processing object of the ordinary polishing machine is the print of flatbed paper, and its main structure consists of a feeding plate (or paper feeding structure), a transmission structure, an electrical control device, a coating structure, a conveyor belt, a drying device, an exhaust device, and a delivery paper. Devices and so on. Due to the different characteristics of the coating material, the ordinary coating machine has a thick paper type (also known as a special type) polishing machine and a general-purpose type coating machine that can adapt to a thick and thin paper. Thick paper machine mostly semi-automatic structure, generally suitable for the ration of 200g/m2 above the amount of printed sheets. General-purpose polishing machine is generally a fully automatic structure, and has good adaptability to the coating of thick and thin sheets. The drying mode of the special glazing machine has two structures: solid conduction heating and radiation heating and drying.

2) Structure and characteristics of printing machine polishing

The use of lithographic, letterpress (including flexo, stickers) printer can also be partial or full-width glazing, the glazing is the use of ink and rubber rollers to transfer gloss oil, with PS version (plano) and blanket; The surface of the printed sheet is coated with a copper, zinc plate, rubber plate, or resin plate, and the pressure of the platen or plate is used to transfer the varnish of the blanket or plate surface onto the printed sheet. Due to the slow drying speed of the printing machine, the coating thickness of the coating has certain limitations. The gloss of the coating on the printed product is not as good as the coating effect of the special coating machine. It is generally suitable for ordinary prints with low quality requirements. The glazing.