The micro-gravure coating method uses a gravure roll, the gravure roll surface is mounted on bearings, partially immersed in the feed pan, and the rotating shaft picks up the coating,

After quantification by a flexible rigid scraper, the coating liquid is taken away by the reverse motion substrate to achieve uniform thin layer coating.

The direction of rotation of the microgravure coating gravure roll is opposite to the direction of movement of the film base, and coincidence means that there is no backing roll to press the base onto the gravure roll. If the running direction of the film base is consistent with the direction of the gravure roll, the material will be separated, one part goes to the film base, and the other part stays on the gravure roll.

The advantages of micro gravure coating are as follows

1) Very thin coating can be applied to very thin materials, since there is no back pressure roller, there are no defects such as offset printing and wrinkles on the coating surface;

2) Since the doctor blade touches the anilox roller lightly, the wear of both the doctor blade and the anilox roller is relatively small;

3) The diameter of the micro-groove roller is small, light in weight, and it is convenient to replace the micro-groove roller with different coating amounts;

4) Reverse coating can obtain relatively smooth coating, and the coating amount is evenly distributed.

Light-shielding film for dimple coating, various optical films, materials for lithium batteries, various adhesive tapes for lamination,

Film film, protective film, etc.

Disadvantages and solutions of micro-gravure coating machine

The causes of micro-gravure coating defects are the same as other coating methods: the cleanliness of the coating environment, the stability of the coating system, the cleanliness of the equipment environment, the stability of the coating system, the accuracy of equipment manufacturing and installation, the speed and tension control accuracy , material uniformity, substrate uniformity, etc. In addition, it is also affected by the structure of the gravure roll itself, the capillary number Ca, the speed of the film base, the wrap angle, the degree of cleaning of the gravure roll, etc.

Common disadvantages in the micro-gravure coating process include horizontal lines, thin vertical lines, vertical lines, ribs, air entrainment, decoating, uneven coating or difficult to control thickness, electronics, poor leveling, etc.

stripes

Causes: runout error of gravure roller; motor vibration; other mechanical vibrations; gravure roller, coupling, bearing, and motor shaft are not concentric; bearing wear is severe; vehicle speed and roll speed are unstable; film road tension is uneven.

Solution: Correct installation of gravure roll and doctor blade system; elimination of vibration due to motor and environment

move; replace bearings on time; improve the accuracy of the entire coating machine transmission system.

Thin vertical road

Causes: The speed of the vehicle is too fast, the roller is too slow, the ratio is large; the pressure of the scraper is high or the blade is not installed flat

The whole; the substrate tension is small and the control accuracy is poor; the wrap angle is small

Solution: adjust the appropriate ratio; adjust the initial pressure of the scraper and install the blade correctly; adjust the tension

Size; suitable wrap angle.

Vertical road

Causes: The material bubbles on the gravure roll and air entrainment form relatively large bubbles; high viscosity;

High roller speed, high vehicle speed; the gap and coating wet thickness ratio is too large, and the coating is thin.

Solution: Install a suitable baffle on the feeding tray to eliminate air bubbles in the material; low viscosity; low roller speed,

Low speed; thick wet cover thickness.

Uneven coating or difficult to control thickness

Causes: scraper wear, or uneven pressure; speed and roll speed instability; speed and gravure roll rotation

The speed does not match; the size of the wrap angle is inappropriate; the gravure roll or the wetting roll is deformed; the mesh number of the gravure roll is selected incorrectly; the viscosity, surface tension, and solid content of the material change.

Solution: replace the new blade, adjust the appropriate pressure; improve the accuracy of the entire coating drive system; adjust

Adjust the ratio; adjust the wrap angle; place the gravure roller vertically to replace the wet roller; choose the appropriate mesh number of the gravure roller; the material unity.

Little spot

Cause: The surface tension of a certain part of the substrate is different, resulting in a non-wetting point; the material contains impurities or

Precipitates; there is solid ion accumulation in the mesh and partly removed to form naked spots; the porosity of the substrate.

Solutions: substrate uniformity; vacuum filtration.

Poor leveling

Causes: The viscosity and surface tension of the material are not suitable; the choice of solvent is too single and the volatilization speed is too fast;

Substrate does not match surface tension of material; coating is too thin.

Solution: adjust the viscosity surface tension; use a variety of mixed solvents; improve the surface tension of the substrate

Force, reduce the surface tension of the material; replace the gravure roller to increase the mesh number.