Application of bead mill in the printing ink industry

Sand mill is also called bead mill. A type of grinding and dispersing equipment for solid-liquid phase dispersion of powdery materials and liquid materials. As the grinding medium, a sand mill was initially used, so it was called a sand mill; later, glass beads were used, so it was also called a bead mill. The grinding media currently used are sand grains with rounded corners, beads made of various glass or wear-resistant materials, steel balls, and steel shavings. This kind of wet ultrafine grinding equipment is widely used in the dispersion and grinding of pigments in the ink production process.

bead mill

A rotating shaft is axially inserted into the vertical or horizontal cylinder, and several grinding discs, rings, or pins are installed radially on the rotating shaft. The cylinder is filled with grinding media with a particle size of 0.6-2mm. The simplified version is equipped with a jacket with cooling water in the middle to absorb and dissipate the heat generated during the grinding and dispersing process. The material is pumped into the barrel, together with the grinding medium, it is strongly stirred by the high-speed rotating grinding disc, and it is thrown along the disc to the wall of the cylinder and back again. The slurry flow reciprocates between the discs so that the solid material is gradually evenly dispersed in the liquid material. middle. The method of unloading varies with the viscosity of the material. Generally, the suspension can be used to flow out through a screen with slit holes, and the width of the holes is 1/2-1/3 of the grinding medium. The bead mill is a device that uses hard and wear-resistant zirconium beads, glass beads, etc. to rotate in a closed cavity to grind pigments.

sand mill

Different types of ink used bead mills in different structures

Intaglio ink production generally uses pin rods (5-50 liters) or disc bead mills (10-100 liters).

Rotary offset printing inks generally use vertical rod type (5—130 liters) or horizontal disc type bead mills (60 to 500 liters), while the production of ultra-high viscosity sheet-fed inks often uses high energy density cone bead mills or three roll mills.

Inkjet inks (inks and pigment solvent-based inks) generally use high-energy-density pin-type (horizontal or vertical) bead mills and turbo-centrifugal nano-bead mills.

The new bead mill is the main grinding and dispersing equipment in the ink production process. The bead mill is a fully enclosed grinding equipment with automatic feeding, automatic temperature, and pressure control devices, and can carry out continuous production operations.

When the bead mill is running, the rotor agitates the meson (beads) to move at a high speed, and the high-speed running medium and the grinding cavity plays a role of dispersion through impact, friction, and shear. The vertical bead mill is a fully enclosed type, which can continuously grind and disperse granular and non-granular solid materials in liquid.

sand mill

The structure and characteristics of the bead mill are:

①For grinding different varieties, the computer can input the pump flow rate, heating time, grinding chamber pressure, material temperature, and other technical data in advance according to the characteristics of the variety, and then the computer can automatically control it according to the input program.

②The annular groove on the stator can meet the different requirements of the product, and the high-precision special isolation groove can be used for the special viscosity.

③The temperature, pressure, feed pump flow rate of the rotor and stator are automatically displayed, and there are protection devices such as temperature and pressure.

④The grinding efficiency and dispersion degree can be obtained by adjusting the flow rate of the feed pump and the filling amount of the beads.

⑤Due to the use of special and latest technical materials, the grinding area and the isolation area are particularly wear-resistant, and will not affect the hue of the material.

⑥Bead mills usually have safety self-locking and alarm devices, and some faults can be automatically eliminated.

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Source: Franli

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