Sand Mill Machine｜Sand Mill For Paint

Many factories and enterprises spent tens of thousands of yuan to buy a sand mill for paint. After using it for less than two months, various problems occurred in the sand mill. The rotors and stators have been worn so badly that many types of equipment are almost paralyzed and can no longer be used. What is the reason for this? How to buy a machine with the most cost-effectiveness?

The standard for judging the quality of a sand mill generally starts from two aspects:

1. The material used in the manufacture of the sand mill.
2. The manufacturer’s process for producing the sand mill.​​

how to judge the quality of the material?

First of all, we have to manufacture the sand mill under normal use, but the sand mill is still largely damaged. The main reason for the lack of wear resistance must be the material problem of the machine:

l In order to reduce the cost and sales price of the machine, the manufacturer of the sand mill generally chooses low-grade raw materials, so it is also very important to choose a high-quality sand mill manufacturer.

l For the same material, the processing technology is different, and the hardness of the sand mill will be different, whether it is high wear-resistant alloy steel or polymer, cemented carbide, polyurethane, and ceramics. But not all high wear-resistant alloy steels, cemented carbides, polyurethanes, and ceramics are created equal. Under normal circumstances, the higher the processing cost, the better the quality.

The quality of the material is generally difficult to judge accurately by intuition. But we also can’t do destructive testing. Under normal circumstances, a test machine can be judged immediately. For example, discoloration when grinding white, and when grinding those special raw materials such as carbon black iron-red titanium cyan blue, the fineness does not meet the requirements, and the gloss is not good. This is because the originally selected sand mill and the materials you are grinding are not reasonable. According to the viscosity, hardness, color, and fineness of the grinding materials, different grinding inner barrels, grinding media, and zirconium bead diameters should be selected.

The cost price of high-quality materials is definitely much higher, so the price of the whole machine should also increase a lot. Relatively speaking: the higher the price, the better the quality of the machine! So, will the price of domestic machines and the quality of imported machines be just a slogan? no! In addition to process improvement, there is one more important point – the essential difference between high-quality domestic machines and imported machines! That is the material of the grinding inner barrel and the grinding medium, the complexity of the grinding structure, the sealing method, the size of the motor and the quality of the motor, etc.

If the material is not good enough, the following problems often occur:

1. The fineness is not enough
2. The gloss is not bright enough
3. Easy to change color
4. The purity of the finished product is not enough
5. Reduced efficiency
6. Increase energy consumption

Of course, when choosing the material of the grinding medium and the grinding inner barrel, you should actually provide you with the material of the grinding medium and the material of the grinding inner barrel according to the viscosity, hardness, required fineness, and chromaticity of the grinding material, etc. Choose the best sander for you

For example, the advantage of alloy steel is that the price is relatively cheap, but it may have a certain impact on the color of the material. For example, polyurethane is soft and hard. If your material has a high hardness and can be adapted to work at high temperatures, then polyurethane can be very It is suitable for your choice, which can greatly reduce the wear on the inner barrel and sand grinding disc of the sand mill, and greatly improve the service life of the sand mill.

If the only disadvantage of the higher-end silicon carbide grinding inner barrel is fear of freezing and expansion, that is, if you forget to put water in winter, the inner barrel will freeze and crack.

The material of ceramics is expensive but has a wide range of applications, which does not affect the grinding quality, including grinding fineness, whiteness, wear, etc. so the so-called “what you pay for what you pay for” is essentially the difference between these materials. Unless you’re producing very low-end paint and paint products and you don’t plan to produce good quality paint in the short term, it’s still a good idea to get it right the first time!

Sand mill is one of the key pieces of equipment for fine material preparation. It is also called bead mill or ball mill. It is also called agitated ball mill (a combination of agitating shaft ball mill) abroad.

In principle, sand mills, ball mills, and mixers all use the grinding medium to give it enough kinetic energy under the action of the high-speed rotation of the dispersing blades, so that the impact and extrusion between the grinding medium and the grinding material will generate shear force. To the grinding effect. With the high-performance cooling system and automatic control system, the sand mill can realize continuous processing and continuous discharging of materials, which can greatly improve production efficiency.

There are many types of sand mills, and they have gone through different stages of development from birth to maturity. With the continuous iterative innovation of technology, grinding equipment with different styles and principles have gradually appeared on the market to meet different production needs.

According to the layout of the grinding drum, it can be divided into vertical sand mills and horizontal sand mills. These are two very common styles. Next, we will learn more about the characteristics, advantages, and working principles of the two sand mills.

The vertical sand mill is mainly composed of a feed system, grinding drum, grinding disc, transmission, and electric control system.

Working principle of vertical sand mill

When the vertical sand mill is working, most of the grinding cylinder is filled with grinding media, which is made of ceramics or special materials, and the shape is spherical particles of different sizes. Add the material from the bottom of the vertical silo and mix it with the grinding medium. The stirring shaft is driven by the transmission system to stir the mixture of materials and media at an appropriate speed. Due to the friction and collision between the grinding media, the material is ground, and after a certain residence time, a slurry with a particle size distribution meeting the requirements is obtained.

The horizontal sand mill mainly has the following components: machine base, main shaft components, grinding device, cooling device, control system, auxiliary device, etc. It is a continuous production ultrafine grinding and dispersing machine with a horizontal cylinder, which is widely used It is used for grinding fluid slurry in paint, coating, ink, electronics, ceramic materials, and other industries.

Horizontal sand mill working principle

The horizontal sand mill uses a material pump to feed the solid-liquid phase mixture that has been pre-dispersed and wetted by the mixer into the cylinder. The material and the grinding medium in the cylinder are stirred by a high-speed rotating disperser so that The solid particles and the grinding media produce stronger collision, friction, and shearing effects with each other to achieve the purpose of accelerating the grinding of fine particles and dispersing aggregates. After grinding and dispersing, the material passes through a dynamic separator to separate the grinding media and flows out of the discharge pipe. The horizontal sand mill is especially suitable for dispersing and grinding products with high viscosity and fine particle size requirements.

Vertical sand mill VS horizontal sand mill

The application of sand mills in the industrial field is becoming more and more extensive, and people’s research on them is becoming more and more in-depth. Whether it is a vertical sand mill or a horizontal sand mill, its structure is constantly being improved, and only by understanding the characteristics of the two pieces of equipment can we choose a cost-efficient product that meets the production requirements according to the needs.

Manufacturing difficulty

From the perspective of manufacturing difficulty, the vertical sand mill does not require the use of mechanical seals, so it is easier to manufacture and the manufacturing cost is correspondingly lower.

Material

In terms of materials, vertical sand mills generally use ordinary materials, while horizontal sand mills generally use tungsten carbide metal materials with better materials.

In terms of manufacturing difficulty and manufacturing cost, vertical sand mills have more advantages. In addition, the vertical sand mill does not take up space, and the operation is very convenient, which is suitable for materials with various viscosities. If you have a small budget or do not have high requirements for the fineness of the material, the vertical sand mill will be a very cost-effective choice.

Compared with the vertical sand mill, the horizontal sand mill has a relatively high price, but its advantages are also obvious.

Grinding fineness

From the perspective of grinding fineness, the grinding effect of horizontal sand mills is often better, which can meet the fineness requirements of the product. This difference is limited by the structure of the vertical sand mill.

The grinding medium (beads) in the vertical sand mill is affected by gravity and tends to accumulate to the bottom of the grinding cavity, resulting in a less uniform particle size distribution of the ground material, resulting in a better grinding effect at the bottom than at the top. This is like a bucket of stones, the stones on the bottom of the bucket are ground finer than those on the top of the bucket.

The horizontal sand mill can well overcome the influence of gravity on the medium. Because the feed of the horizontal sand mill is generally from the left to the right, the grinding force of the material in the barrel is the same, the particle size distribution of the output material will be more uniform, and the grinding fineness is generally up to 1μm.

The cost

When shutting down, the grinding media (beads) of the vertical sand mill gather at the bottom of the grinding chamber. When the machine is turned on, the blades will have strong friction with the beads. Because the grinding beads are too concentrated, it is very easy to break the beads. The horizontal type has a lower probability of such a situation.

Scope of application

Vertical sand mills are more suitable for manufacturing products that require relatively low product requirements but require high output. A horizontal sand mill is suitable for some grinding products with higher precision and fineness.

At present, sand mills are developing in the direction of large batches, refinement, high purity, and low energy consumption. Equipment maintenance is the key to extending the life of mechanical products, and it is also related to the stability and efficiency of production. Understand the common faults of sand mills and their solutions to reduce production losses caused by unnecessary equipment downtime.