The choice of magnetic product cleaning method?

The placement of magnetic products in the cleaning tank has a great relationship with the cleaning quality, and its placement is also related to the size, shape and structure of the workpiece. Generally speaking, the overlapping stacking of workpieces, or too much stacking at one time will affect the cleaning effect.

 Although NdFeB magnetic materials have different shapes, most of them are small parts. It can be placed on a nylon net and shaken and cleaned in the cleaning tank, which helps the dirt on the surface of the workpiece to fall off, and is also conducive to the destruction of the water film of the workpiece with blind holes, making it easy to produce cavitation effects in the blind holes. Another way of placement is to directly flatten the workpiece on the bottom plate of the cleaning tank (that is, the radiation plate of the ultrasonic transducer), so that the workpiece is subjected to strong ultrasonic impact. Practice has proved that this method of directly placing the workpiece on the bottom plate for cleaning has the best cleaning effect and the highest efficiency.

What precautions should be taken during the transportation of magnets?

Pay attention to the humidity in the room, which must be maintained at a dry level. The temperature should not exceed room temperature; when storing products in the black block or rough state, oil can be properly applied (ordinary engine oil is enough); electroplated products should be stored in a vacuum seal or isolated from the air to ensure the corrosion resistance of the coating; magnetized products should be closed Store together and in a box to avoid picking up other metal objects; magnetized products should be stored away from disks, magnetic cards, tapes, computer monitors, watches and other objects that are sensitive to magnetic fields. The magnet should be shielded when transported in a magnetized state, especially air transport must be completely shielded.


What is a strong magnet?

 Powerful magnets refer to NdFeB magnets. Its magnetic properties greatly surpass those of ferrite magnets, alnico, and samarium cobalt. NdFeB magnets can absorb 640 times their own weight, so NdFeB magnets are often called powerful magnets by outsiders.


How to demagnetize the powerful magnet?

 According to the use of strong magnets, a certain method can be formulated for demagnetization.

High temperature demagnetization method: The main operation of the high-temperature demagnetization method is to put the magnet into a high-temperature furnace for heating. After high-temperature treatment, the magnetism of the strong magnet will be removed. However, during the heating process, the high temperature will directly cause the structure of the object inside the magnet. Drastic changes occur, so this method of demagnetization is generally used for scraped and recycled magnets.

Vibration demagnetization method: The operation of this method is very simple. It is to vibrate the powerful magnet strongly and violently. After the operation of the vibration, the internal structure of the magnet changes, thereby changing the physical properties of the magnet. Generally speaking, the effect of this demagnetization method is adopted. Not big, only a small amount of demagnetization can be used temporarily.

Magnet AC demagnetization method: This demagnetization method is to put the magnet into a space that can generate an AC magnetic field. After the AC magnetic field is disturbed, the internal structure of the magnet will be disrupted, so that the effect of demagnetization can be achieved. This method is relatively common. The method of demagnetization.

The above three methods are effective for the demagnetization of strong magnets, but in general we still prefer the AC demagnetization method. It has a better demagnetization effect than the high temperature demagnetization method and vibration demagnetization method, and the efficiency is also high. It is the most widely used in industrial production at present. method.


How to test the coating quality?

The quality of the coating directly affects the service life of NdFeB coatings. The main methods for testing the quality of NdFeB coatings are:

Appearance visual inspection the appearance is mainly observed with the naked eye, and it is best observed under natural light (sunlight, non-direct sunlight), or under a fluorescent lamp with an illumination equivalent to 40W. There should be no blistering, peeling, partial failure to coat, uneven color tone, stains, water stains, etc.

Coating thickness measurement

Drop test (mainly for galvanized products)

Cross-cut test (generally used for nickel-plated products)

Cold and heat test

PCT pressure test

SST salt spray test

Constant temperature and humidity test, etc.


What should be paid attention to when measuring the particle size distribution of NdFeB powder with laser particle size analyzer?

NdFeB particles have strong magnetism, and the average particle size is generally measured by the air-permeable method. At present, it is mainly used for the dry laser particle size analyzer to measure the particle size distribution. NdFeB powder has spontaneous combustion characteristics in the air. When the ambient temperature is slightly higher or its concentration reaches a certain level, it will spontaneously ignite. It often ignites the vacuum cleaner pipeline and filter and burns the vacuum cleaner. The following measures to prevent spontaneous combustion should be adopted:

use inert gas such as high-pressure nitrogen as the gas source;

replace the vacuum cleaner tube with a smooth polyethylene tube so that particles do not deposit in the tube;

choose Water filtered vacuum cleaner.


Which motors will use NdFeB magnetic tiles?

NdFeB is a permanent magnet material and an indispensable part of permanent magnet motors. Rare earth permanent magnet motors are the largest application field of NdFeB magnets, accounting for about 70% of the total magnets. The coil motors (VCM) account for 40% to 50%, so the computer industry is the largest user of permanent magnet motors. Common permanent magnet motors are: permanent magnet DC motor, permanent magnet AC motor. Permanent magnet DC motors include: brushed DC motors, brushless motors, stepper motors, etc. Permanent magnet AC motors include: synchronous permanent magnet motors, permanent magnet servo motors, etc.


How to apply NdFeB magnetic tiles in brushless motors?

Everyone knows that NdFeB magnetic tiles or NdFeB radial magnetic rings are as important as the human heart in motor products. After the current is energized, the magnetic field generated by the coil drives the NdFeB magnetic tiles or NdFeB radial magnetic rings. Ring magnetic field, so the magnetic field strength of NdFeB magnetic tiles or NdFeB radial magnetic rings is very important for motor operation efficiency. Let us first look at the advantages of brushless motors:

Brushless, low interference the brushless motor removes the brush, and the most direct change is that there is no electric spark generated when the brushed motor is running, which greatly reduces the interference of electric sparks on remote control radio equipment.

Low noise and smooth operation the brushless motor has no brushes, the friction force is greatly reduced during operation, the operation is smooth, and the noise will be much lower. This advantage is a huge support for the stability of the model operation.

Long life, low maintenance cost and fewer brushes. The wear of brushless motors is mainly on the bearings. From a mechanical point of view, brushless motors are almost maintenance-free motor. When necessary, only need to do Some dusting maintenance will do. Brushless motor, as the name implies, definitely does not need the original carbon brush. A magnetic field that rotates around the geometric axis of the motor is formed around the winding coil. This magnetic field drives the permanent magnet steel on the rotor to rotate, and the motor rotates. The performance is related to factors such as the number of NdFeB magnetic tiles, the magnetic flux intensity of the NdFeB radial magnetic ring, and the input voltage of the motor. The brushless electronic governor really determines its performance. A good electronic governor needs to have the single-chip microcomputer controls the overall control of program design, circuit design, complex processing technology and other processes, so the price is much higher than that of brushed motors.

What is the performance comparison between ferrite and NdFeB?

Appearance: The ferrite is loose and has no metallic luster. Generally, it is not electroplated, and it is usually black. NdFeB basically needs to be electroplated, otherwise it is easy to rust. The surface has a silvery white metallic luster. Magnetic force: According to the investigation data, the ferrite magnetic force is usually 800-1000 Gauss, and the density is 5 (g/cm3). In the state of bare magnets, the magnetic force of NdFeB can reach about 3500 Gauss. The density is 7.5 (g/cm3). In terms of performance: the temperature resistance and stability of ferrite are very good. In contrast, the ordinary temperature resistance of NdFeB is only 80 degrees. And the price is also cheap. NdFeB: NdFeB has the characteristics of small size, light weight and strong magnetism, and its magnetism is completely different from that of ferrite. In terms of price: ferrite is usually cheap, and many are calculated on a piece-by-piece basis. The price is affected by the shape, size, and processing difficulty of the ferrite. NdFeB: Now the price of NdFeB changes almost every day, depending on the grades you need to use and special requirements.


How to preserve NdFeB magnetic materials?

Do not approach NdFeB magnets to electronic equipment, because the magnet itself has positive and negative poles, and there is a circuit loop. If it is closed, it will affect the electronic equipment and control loop and affect the use.

Do not store the magnet in a humid environment to avoid its oxidation, resulting in changes in appearance, physical properties and magnetic properties.

People who are sensitive to metal objects will have rough and red skin if they get close to the magnet. If the above reaction occurs, please do not touch the magnet.

Do not put magnets close to floppy disks, hard drives, credit cards, tapes, credit cards, TV picture tubes, etc. If a magnet is brought close to a device such as a magnetic recorder, it will affect or even destroy the recorded data.

Pay attention to the following aspects:

Do not place magnets near strong currents;

The magnet cannot be baked on the fire, after high temperature;

The magnet cannot be knocked and violently vibrated;

Small magnets cannot be placed together with large magnets;

The hoof magnet should also add a piece of soft iron to the two poles to connect the two poles, and invert the north and south poles of the adjacent magnets;

Small magnets (such as magnetic needles) cannot be placed together with large magnets.

When storing NdFeB magnets, the requirement for the environment is to dry, and to prevent the NdFeB magnets from encountering chemicals such as acids and bases, so as not to affect the NdFeB magnets, corrosion, rust, etc. Phenomenon. Therefore, placing NdFeB magnets on a layer of wood has a good effect on avoiding moisture. Always be very careful when storing magnets, as the magnets will stick together and can pinch your fingers. There is also the possibility of damage to the magnet itself (knocking off corners or knocking cracks) due to collisions when the magnets are attracted to each other.



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