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NdFeB magnets are produced by powder metallurgy process. They are a kind of powder material with strong chemical activity. There are tiny pores and cavities inside them, which are easily corroded and oxidized in the air. After the material is corroded or the components are damaged, the magnetic properties will be attenuated or even lost over time, thus affecting the performance and life of the whole machine. Therefore, strict anti-corrosion treatment must be carried out before use.   At present, the anti-corrosion treatment of NdFeB generally adopts electroplating, chemical plating, electrophoresis, phosphating and other methods. Among them, electroplating is the most widely used as a mature metal surface treatment method.   NdFeB electroplating uses different electroplating processes according to the different product use environments, and the surface coatings are also different, such as zinc plating, nickel plating, copper plating, tin plating, precious metal plating, etc. Generally, zinc plating, nickel plating + copper + nickel plating, nickel plating + copper + chemical nickel plating are the mainstream processes. Only zinc and nickel are suitable for direct plating on the surface of NdFeB magnets, so multi-layer electroplating technology is generally implemented after nickel plating. Now the technical difficulties of direct copper plating of NdFeB have been broken through, and direct copper plating and then nickel plating is the development trend. Such a coating design is more conducive to the thermal demagnetization index of NdFeB components to meet customer needs. The most commonly used coatings for NdFeB strong magnets are zinc plating and nickel plating. They have obvious differences in appearance, corrosion resistance, service life, price, etc.:   Polishing difference: Nickel plating is superior to zinc plating in polishing, and the appearance is brighter. Those who have high requirements for product appearance generally choose nickel plating, while some magnets are not exposed and the requirements for product appearance are relatively low. Generally, zinc plating is used.       Difference in corrosion resistance: Zinc is an active metal that can react with acid, so its corrosion resistance is poor; after nickel plating surface treatment, its corrosion resistance is higher.   Difference in service life: Due to different corrosion resistance, the service life of zinc plating is lower than that of nickel plating. This is mainly reflected in the fact that the surface coating easily falls off after a long time of use, causing oxidation of the magnet and thus affecting the magnetic properties.   Hardness difference: Nickel plating is harder than zinc plating. During use, it can greatly avoid collisions and other situations that may cause corner loss and cracking of NdFeB strong magnets.   Price difference: Zinc plating is extremely advantageous in this regard, and the prices are arranged from low to high as zinc plating, nickel plating, epoxy resin, etc.   When choosing NdFeB strong magnets, it is necessary to consider the use temperature, environmental impact, corrosion resistance, product appearance, coating bonding, adhesive effect, and other factors when choosing the coating.    

Many customers may have a question: do magnets of the same performance and volume have the same suction force? It is said on the Internet that the suction force of NdFeB magnets is 640 times its own weight. Is this credible?   First of all, it should be made clear that magnets only have adsorption force on ferromagnetic materials. At room temperature, there are only three types of ferromagnetic materials, they're iron, cobalt, nickel, and their alloys. They have no adsorption force on non-ferromagnetic materials.   There are also many formulas on the Internet for calculating suction. The results of these formulas may not be accurate, but the trend is correct. The strength of the magnetic suction is related to the magnetic field strength and the adsorption area. The greater the magnetic field strength, the larger the adsorption area and the greater the suction.   The next question is, if the magnets are flat, cylindrical, or elongated, will they have the same suction force? If not, which one has the greatest suction force?       First of all, it is certain that the suction force is not the same. To determine which suction force is the greatest, we need to refer to the definition of the maximum magnetic energy product. When the working point of the magnet is near the maximum magnetic energy product, the magnet has the greatest work energy. The adsorption force of the magnet is also a manifestation of work, so the corresponding suction force is also the greatest. It should be noted here that the object to be sucked needs to be large enough to completely cover the size of the magnetic pole so that the material, size, shape, and other factors of the object to be sucked can be ignored.   How to judge whether the working point of the magnet is at the point of maximum magnetic energy product? When the magnet is in a state of direct adsorption with the material being adsorbed, its adsorption force is determined by the size of the air gap magnetic field and the adsorption area.    Taking a cylindrical magnet as an example, when H/D≈0.6, its center Pc≈1, and when it is near the working point of maximum magnetic energy product, the suction force is the largest. This is also in line with the rule that magnets are usually designed to be relatively flat as adsorbents. Taking the N35 D10*6mm magnet as an example, through FEA simulation, it can be calculated that the suction force of the adsorbed iron plate is about 27N, which almost reaches the maximum value of magnets of the same volume and is 780 times its own weight.   The above is only the adsorption state of a single pole of the magnet. If it is multi-pole magnetization, the suction force will be completely different. The suction force of multi-pole magnetization will be much greater than that of single-pole magnetization (under the premise of a small distance from the adsorbed object).     Why does the suction force of a magnet of the same volume change so much after being magnetized with multiple poles? The reason is that the adsorption area S remains unchanged, while the magnetic flux density B value through the adsorbed object increases a lot. From the magnetic force line diagram below, it can be seen that the density of magnetic force lines passing through the iron sheet of a multi-pole magnetized magnet is significantly increased. Taking the N35 D10*6mm magnet as an example, it is made into a bipolar magnetization. The suction force of the FEA simulation adsorbing the iron plate is about 1100 times its own weight.     Since the magnet is made into a multi-pole magnet, each pole is equivalent to a thinner and longer magnet. The specific size is related to the multi-pole magnetization method and the number of poles.        

The main reasons why magnetic materials are magnetic can be attributed to the following points: Magnetic materials, the raw materials used in neodymium magnet production, exhibit magnetism due to the alignment of their atomic structure. At the core of their behavior are electrons, which act as tiny magnetic dipoles. In other materials, these dipoles cancel each other out. However, in neodymium magnetic materials, a significant number of these dipoles align in the same direction, creating a unified magnetic field.   Neodymium magnets, the strongest type of permanent magnets, have exceptional magnetism due to their unique composition and density of neodymium magnet material. They are made from a blend of neodymium, iron, and boron, which, when processed and magnetized, form a crystal structure capable of sustaining a strong magnetic force. This structure allows for the concentration of a magnetic field in a compact area, resulting in the remarkable neodymium magnet force observed in various applications.     The production process further enhances this magnetic capability. During neodymium magnet production, the material is sintered and aligned in a magnetic field to ensure maximum dipole alignment. This precise manufacturing process contributes to the magnet's high coercivity and strength.   These characteristics make neodymium magnets essential for applications ranging from electric motors to renewable energy devices. Their great magnetic properties originate from the atomic level, amplified by advanced production techniques and material density, ensuring reliable and powerful performance.

Correct selection of permanent magnet motor power   Demagnetization is related to the power selection of the permanent magnet motor. Correctly selecting the power of the permanent magnet motor can prevent or delay demagnetization. The main reason for the demagnetization of the permanent magnet synchronous motor is excessive temperature, and overload is the main reason for excessive temperature.   Therefore, when selecting the power of the permanent magnet motor, a certain margin should be left. According to the actual load situation, about 20% is generally more appropriate.     Avoid heavy load starting and frequent starting   Cage-type asynchronous starting synchronous permanent magnet motors should avoid heavy-load direct starting or frequent starting.   During the asynchronous starting process, the starting torque is oscillating. In the starting torque trough section, the stator magnetic field has a demagnetizing effect on the rotor poles. Therefore, try to avoid heavy-load and frequent starting of asynchronous permanent magnet synchronous motors.   Improved design   1. Properly increase the thickness of the permanent magnet   From the perspective of permanent magnet synchronous motor design and manufacturing, the relationship between armature reaction, electromagnetic torque and permanent magnet demagnetization should be considered.   Under the combined effect of the magnetic flux generated by the torque winding current and the magnetic flux generated by the radial force winding, the permanent magnet on the rotor surface is prone to demagnetization.   In the case of the motor air gap remaining unchanged, the most effective way to ensure that the permanent magnet does not demagnetize is to appropriately increase the thickness of the permanent magnet.   2. There is a ventilation slot circuit inside the rotor to reduce the rotor temperature rise   If the rotor temperature rises too high, the permanent magnet will lose its magnetism irreversibly. When designing the structure, a ventilation circuit can be designed inside the rotor to directly cool the magnetic steel. This not only reduces the magnetic steel temperature, but also improves efficiency.

The food processing industry is a rigorous and high-quality field, and ensuring food safety and quality is very important. Neodymium rod magnets are widely used in food processing as a key tool to remove possible ferromagnetic impurities such as metal fragments, iron filings, and magnetic particles. The following are the applications and advantages of neodymium rod magnets in the food processing industry:   Food production line   Neodymium rod magnets are usually installed in food production lines, in the flow of raw materials, or finished products. These production lines include bakeries, confectionery factories, meat processing plants, beverage production, etc. Neodymium rod magnets are able to capture metal impurities such as nails, screws, iron filings, etc., ensuring that these impurities do not enter the final product.   Raw material handling   In the food manufacturing process, raw materials may include iron ore, grains, spices, etc. Neodymium rod magnets are used to remove ferromagnetic impurities from these raw materials to ensure the composition and quality of the food.     One of the most important advantages of using neodymium rod magnets is ensuring food safety. By removing metal impurities, neodymium rod magnets help prevent metal fragments from entering food products, reducing potential hazards in food.     In addition to protecting food quality, neodymium rod magnets also help protect production equipment. Preventing metal impurities from entering equipment can reduce maintenance and repair costs and extend the life of equipment.

The biggest risk in the use of permanent magnet motors is demagnetization caused by high temperature. As we all know, the key component of permanent magnet motors is neodymium magnet, and neodymium magnet is most afraid of high temperature. It will gradually demagnetize under high temperature for a long time. The higher the temperature, the greater the risk of demagnetization.   Once a permanent magnet motor loses its magnetism, you basically have no choice but to replace the motor, and the cost of repair is huge. How do you determine whether a permanent magnet motor has lost its magnetism?   1. When the machine starts running, the current is normal. After a period of time, the current becomes larger. After a long time, the inverter will be reported to be overloaded.   First, you need to make sure that the inverter selected by the air compressor manufacturer is correct, and then confirm whether the parameters in the inverter have been changed. If there are no problems with both, you need to judge by back electromotive force, disconnect the head from the motor, perform no-load identification, and run no-load to the rated frequency. At this time, the output voltage is the back electromotive force. If it is lower than the back electromotive force on the motor nameplate by more than 50V, it can be determined that the motor is demagnetized.     2. After demagnetization, the running current of permanent magnet motor will generally exceed the rated value.   Those situations where overload is reported only at low or high speed or occasionally reported, are generally not caused by demagnetization.   3. It takes a certain amount of time for a permanent magnet motor to demagnetize, sometimes several months or even one or two years.   If the manufacturer selects the wrong model and causes current overload, it does not belong to motor demagnetization.   An important indicator of permanent magnet motor performance is the high temperature resistance level. If the temperature resistance level is exceeded, the magnetic flux density will drop sharply. The high temperature resistance level can be divided into: N series, resistant to more than 80℃; H series, resistant to 120℃; SH series, resistant to more than 150℃. The motor's cooling fan is abnormal, causing the motor to overheat. The motor is not equipped with a temperature protection device. Ambient temperature is too high. Improper motor design.

Demagnetization may be caused by a variety of factors, including: high temperature, physical shock or long-term time-induced natural decline in magnetism.   Specifically, when a permanent magnet is subjected to high temperatures, the magnetic dipoles inside it lose their ordered arrangement, causing the magnetism to weaken or disappear.   For example, the Curie temperature of permanent magnets is relatively low, and once their maximum operating temperature is exceeded, the magnets will gradually demagnetize.     In addition, physical shock may also cause demagnetization of permanent magnets because the shock may change the arrangement of magnetic dipoles, destroying the magnetic domain structure and thus affecting the magnetic properties.   Over time, even if a permanent magnet is not subjected to significant physical shock or high temperatures, its magnetism may naturally decay, because the arrangement of the magnetic dipoles may gradually become disordered, resulting in a weakening of the magnetism.   This depends on the external conditions the magnet encounters and the properties of the permanent magnet itself.

The magnetic arc industry is set to thrive in the coming years, driven by advances in the design of permanent magnet motors and the growing demand for neodymium magnets from a wide range of industries.    Magnet Arcs in Motor Design   Permanent magnet motors rely on arc magnets to create consistent magnetic fields in rotors, enabling smoother and more efficient operation. With the increasing adoption of electric vehicles and industrial automation, the demand for high-quality arc magnets is growing. The shift toward renewable energy systems, including wind turbines, is also increasing this demand.   Wholesale Supply and Customization   Wholesale markets for neodymium magnets, including neodymium arc, are expanding rapidly. All manufacturers require magnets that meet high quality and dimensional standards for different uses. Companies like Huajin are equipped to provide customized solutions, addressing specific needs in motor production, medical equipment, and consumer electronics.     Key Applications Driving Growth   Electric Vehicles: Arc magnets are integral to the lightweight, high-performance motors that power modern EVs. Renewable Energy: Permanent magnet generators in wind turbines utilize arc magnets for consistent energy conversion. Industrial Tools: Precision tools and machinery benefit from the reliable strength of neodymium arc magnets.   For businesses seeking dependable supply and innovation, Nanjing Huajin Magnet Co., Ltd. offers unmatched expertise in the production of high-performance neodymium magnets. With a focus on customization, quality, and scalability, Huajin is poised to support the evolving demands of this dynamic industry.     For more details about our products and solutions, explore our offerings on neodymium magnets and their applications. Let's shape the future of magnetic technology together!          

As a high-performance magnetic material in modern industry, NdFeB permanent magnets promote the progress of contemporary technology and society and are widely used in various fields. How to judge the advantages of permanent magnet products: 1. Magnetic properties; 2. The size of the magnet; 3. Surface coating.   1. Magnetic properties：First, the key to the decision is to control the magnetic properties of the raw materials during the production process.   Raw material manufacturers can choose mid-range or low-grade sintered NdFeB according to business needs. In accordance with the national standards for purchasing raw materials, our company only sells high-grade NdFeB.   The quality of the production process also determines the performance of the magnet.   Quality control during production is important.     2. Magnet shape, size and tolerance: Utilize various shapes of NdFeB magnets, such as round, special-shaped, square, arc-shaped, trapezoidal. Different sizes of materials are processed by different machine tools to cut rough materials, the technology and machine operator determine the accuracy of the product.   3. Surface coating treatment: The coating quality of the surface coating, zinc, nickel, nickel-copper-nickel electroplating copper and gold and other electroplating processes. The product can be electroplated according to customer requirements.   The quality of NdFeB products can be summarized as a good grasp of performance, dimensional tolerance control, and appearance inspection and evaluation of the coating. Tests such as the Gaussian surface of the magnetic flux of the magnet; dimensional tolerance, which can be measured with a vernier caliper; coating, coating color and brightness and coating bonding strength, and the appearance of the magnet surface can be observed to be smooth, with or without spots, and with or without edges and corners, to evaluate the quality of the product.

When we want to clearly state the purchase demand for a neodymium magnet, there are several key points that need to be clarified: performance requirements, shape and size, magnetization direction, and surface treatment requirements. The purchaser is advised to provide drawings of the magnet. Below we take NdFeB permanent magnets as an example to explain in detail.   1. Performance requirements:   That is, the requirements for the grade of magnets. There are many suppliers in the magnetic material industry, and each neodymium magnet factory has different definitions and performance ranges for the same grade. When communicating the brand, it is recommended that both the supply and demand parties clarify the remanence Br and intrinsic coercivity Hcj of the corresponding brand, so that it is not easy to cause deviations. (If the purchaser is not clear about the product brand, then some auxiliary judgment indicators such as surface magnetism, tension, magnetic flux/magnetic moment, etc.) We usually offer a neodymium magnet grades chart in our catalog.   In addition, according to factors such as the working environment of the magnet, indicators such as remanence and coercivity temperature coefficient can be further clarified. If there are clear requirements for indicators such as magnetic flux, the detection equipment and detection method should be agreed as the judgment standard.     2. Shape, size and magnetization direction:   When describing the purchasing requirements, the neodymium magnets shapes and size requirements of the magnet must be clear, such as 6.0mm (+0.05/-0.05). For simple products, provide basic length, width and height dimensions and tolerances; for magnets with complex shapes, the contour and other angle requirements need to be provided more clearly. It is recommended to provide suppliers with clear drawings.   In addition, the magnet also needs to mark the product's orientation direction (NS pole) and magnetization method (single pole or multi-pole charging), as well as the magnetization angle, etc.   3. Surface treatment requirements:   The purchaser needs to specify the surface treatment method of the magnet, including coating method (electroplating, chemical plating, electrophoresis, vapor deposition, etc.), coating material (zinc, nickel, copper, aluminum, epoxy resin, etc.), and coating thickness.   If there are requirements for salt spray or other tests, the setting of the test conditions, the placement time, and the judgment criteria after the test need to be agreed upon.   4. Other requirements:   Such as: appearance requirements, other testing requirements (such as aging tests, etc.), packaging requirements, transportation requirements, etc.

When choosing a magnetic filter to fit the different shapes of injection molding machines and extruder hoppers, there are several key factors to consider:   1. Hopper shape and size: First, the shape and size of the magnetic filter should match the hopper of the injection molding machine or extruder. For hoppers of different shapes, such as round, square, or other special shapes, the design of the magnetic filter also needs to be adjusted accordingly to ensure that it can fit tightly on the hopper and effectively capture iron impurities.   2. Magnetic strength: The magnetic strength of the magnetic filter is an important consideration when choosing. The magnetic strength should be strong enough to adsorb and capture iron impurities in the hopper, but not too strong to avoid damage to the hopper or the magnetic frame itself. Therefore, when choosing a magnetic filter, it is necessary to determine the appropriate magnetic strength based on the type and amount of iron impurities that may be present in the hopper. All the magnetic filters produced by our factory are made of neodymium magnet material, with magnetic field strength ranging from 8000-14000GS, which can be applied to different needs.   3. Use environment: The working environment of the injection molding machine and extruder may be different, such as temperature, humidity, and dust. Therefore, when choosing a magnetic filter, it is necessary to consider whether it can work properly in this environment. For example, for high temperature or high humidity environments, you should choose a magnetic stand that is resistant to high temperatures and waterproof and moisture-proof!   4. Maintenance and cleaning: The magnetic filter may require regular maintenance and cleaning during use. Therefore, when choosing a magnetic filter, the convenience of its maintenance and cleaning should be considered. For example, some magnetic filters may be designed to be easy to disassemble and clean, which will help reduce maintenance time and costs.   In summary, when choosing a magnetic filter with different hopper shapes for injection molding machines and extruders, it is necessary to consider multiple factors such as hopper shape and size, magnetic strength, use environment, and convenience of maintenance and cleaning.    Communicating with a permanent magnet supplier when choosing a magnetic rack is recommended to ensure that the selected magnetic filter can meet the actual production needs.  

Multi-pole magnetic ring is a kind of ring magnet widely used in the field of motors. The characteristic of multi-pole magnetic ring is that there are many magnetic poles on one magnet, which is usually achieved by using professional magnetizing equipment. Through technological innovation, the stability and assembly problems of the user end are solved. It has become the first choice for servo motors such as power tools and EPS power steering motors.   Multi-pole magnetic rings can be divided into neodymium iron boron multi-pole magnet rings, ferrite multi-pole magnetic rings, rubber magnetic multi-pole magnet rings, and samarium cobalt multi-pole magnet rings according to different materials. Among them, the first three are more common on the market.     Among the above multi-pole magnetic ring materials, the one with the strongest magnetic force is the multi-pole magnetic ring made of NdFeB magnet material. NdFeB magnet is known as the "king of magnets" among magnets. It has a very high remanence and is mainly used in high-performance permanent magnet motors and sensors. In addition, according to different processes, NdFeB multi-pole magnetic rings are divided into sintered NdFeB multi-pole rings and bonded NdFeB multi-pole magnetic rings. The cost of rubber magnetic multi-pole rings and ferrite multi-pole magnetic rings is relatively low, but the magnetic force will be relatively weak.     The most widely used products at present are circular magnetic grids, water pump motors, sweepers, etc. The multi-pole magnetic ring made of samarium cobalt material is the most temperature-resistant multi-pole magnetic ring. The maximum temperature of this material can reach 350 degrees. It is the best magnet used in high-temperature environments. As for the number of poles of the multi-pole magnetic ring, it is also customized according to customer requirements. The highest number of magnetization levels can reach hundreds of poles or even more.   The application of multi-pole magnetic rings is not limited to high-performance permanent magnet motors and sensors, but also includes automobiles, CNC machine tools, household appliances, computers, robots and other fields, showing its important role in the development of automation, precision and permanent magnet motor design, manufacturing technology and control technology.