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How to buy ring magnets

What are ring magnets?

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The ring magnets are ring shaped magnets, which can produce interactive north and south poles after magnetization. The number, position and size of each pole are not obvious because there are usually no marks on the boundary of the poles.
In terms of surface treatment, zinc plating, nickel, nickel copper nickel, or epoxy resin coating are used.

Most of the ring shaped magnets are magnetized axially, that is, the two end faces are strong magnetic surfaces. A small number of customers will also use radial magnetization. According to experience, the general height dimension The ones with larger diameters are more radially magnetized, which are often used in the fields of motors and automation equipment.
Ring magnets are very versatile. They are usually used in scientific experiments. For example, when demonstrating magnetic repulsion, a magnetic ring is passed through a wooden pole. When the same magnetic poles are in contact with each other, they will not touch, as well as magnetic levitation, motors, electroacoustics, salvage, medicine, etc., a lot.

Classification of rare earth ring magnets

Classified by material

  • (1) Alloy permanent magnet materials: including rare earth permanent magnet materials (NdFeB Nd2Fe14B), Samarium Cobalt (SmCo), Aluminum Nickel Cobalt (AlNiCo).
  • (2) Ferrite permanent magnet material (Ferrite).

Type of magnet

Magnets are divided into permanent magnets and soft magnets. Permanent magnets add strong magnetism to make the spin of magnetic materials and the angular momentum of electrons in a fixed direction, while soft magnets add electricity. (also a method of adding magnetic force) when the soft iron is removed by equal current, the magnetism will gradually lose.
Hang the middle point of the bar magnet with a thin line. When it is still, its two ends will point to the South and north of the earth. The end pointing to the north is called the north pole or N pole, and the end pointing to the south is the guide pole or S pole.
If we think of the earth as a big magnet, the geomagnetic north pole of the earth refers to the south pole, and the geomagnetic South Pole refers to the North Pole. Between magnets, the magnetic poles of the same name repel each other and attract the other. Therefore, the compass repels the south pole, the North Pole repels, and the compass and compass attract.

Multipolar magnetic ring

Multipole magnetic ring is a kind of ring magnet widely used in the field of motor. It means that a magnet is charged with many magnetic poles, more than 2 poles. It is generally magnetized by professional magnetizing coils, and each kind of magnetizing coil is normally charged with a kind of magnetic ring.

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According to different materials, multi pole magnetic ring can be divided into NdFeB multi pole magnetic ring, ferrite multi pole magnetic ring, rubber multi pole magnetic ring and samarium cobalt multi pole magnetic ring.
Among the above multipolar magnetic ring materials, the strongest one is the multi-stage magnetic ring made of NdFeB magnet material. Among the magnets, NdFeB magnet is known as “magneto” and has high remanence. In the multipolar magnetic ring, the same specification and magnetic pole, its magnetic force is also the strongest. It is mainly used in the field of high performance permanent magnet motor and sensor. In addition, according to the different process, the NdFeB multi pole magnetic ring is divided into sintered NdFeB multi pole magnetic ring and bonded NdFeB multi pole magnetic ring.
The cost of rubber magnetic multipole ring and ferrite multipole ring is relatively low, but the magnetic force is also relatively weak. At present, the most widely used products are circular magnetic grid, water pump motor, sweeper, etc.
Samarium cobalt multi pole magnetic ring is the most temperature resistant multi pole magnetic ring. The maximum temperature of this material can reach 350 degrees, which is the best magnet used in high temperature environment at present.
As for the number of poles of the multi pole magnetic ring, it is also different according to different customers. The maximum number of poles can be more than 100.

How does the multipole magnetizing coil magnetize the multipole of the magnetic ring?

The multipole magnetizing coil is mainly used to magnetize the multipole rotor magnet of the motor. The shape of the magnet is mainly ring-shaped, so it is often called the rotor magnetic ring of the motor. Because this kind of magnet involves multipole magnetization, we need to use this multipole magnetizing coil to realize it, so our magnet manufacturer will involve the cost of a magnetizing coil (clamp) when quoting, which is such a return Yes, some people will ask, how does the multipole magnetizing coil magnetize the magnetic ring multipole?

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After the multi pole magnetizing coil is processed, when the magnetizing voltage is loaded, the magnetizing coil will form a plurality of solenoid type magnetizing pole heads, and the magnetizing coil will be covered with the magnetic ring to be magnetized. Because the winding direction of the coils on the adjacent magnetizing pole heads is opposite, the magnetizing magnetic field with N and S poles alternately will be formed on the magnetic ring to complete the magnetization.

Bonded NdFeB ring magnet

Bonded NdFeB ring magnet is a magnet made by mixing NdFeB magnetic powder and binder through “pressing molding” or “injection molding”. The size precision of bonded magnet is very high, and it can be made into a relatively complex shape of magnetic element device, and has the characteristics of one-time molding and multipolar orientation. It can be injected into one with other supporting parts during molding.

What are the main characteristics of bonded NdFeB ring magnets?

  • 1. The magnetic properties of bonded NdFeB are much higher than that of ferrite;
  • 2. The bonded NdFeB ring magnet has better dimensional accuracy than sintered NdFeB because it is formed in one step without post machining;
  • 3. Bonded Nd-Fe-B ring magnets can be multi pole magnetized;
  • 4. The working temperature is high, TW = 150 ℃;
  • 5. Good corrosion resistance

Sintered NdFeB Ring Magnet

Sintered neodymium iron boron permanent magnets are smelted after airflow milling. They have high coercivity and extremely high magnetic properties. Its maximum magnetic energy product (BHmax) is more than 10 times higher than that of ferrite. Its own mechanical properties are also quite good, it can cut and process different shapes and drill holes. The maximum working temperature of high-performance products can reach 200℃.
Because of its material content, it is easy to cause corrosion, so the surface must be treated with different coatings according to different requirements. (Such as zinc, nickel, environmentally friendly zinc, environmentally friendly nickel, nickel copper nickel, environmentally friendly nickel copper nickel, etc.). Very hard and brittle, with high resistance to demagnetization, high cost/performance ratio, not suitable for high working temperature (>200℃).

Radial sintered NdFeB ring magnets

The motor is driven by a powerful permanent magnet, the most widely used is sintered neodymium magnet. At present, the radial (multipole sintered NdFeB) magnet has replaced the traditional assembly block or arc magnet and become the mainstream magnet of micromotor.
Radial (multi pole sintered NdFeB) magnetic ring is a relatively mature product, which can significantly improve the output characteristics of the motor and reduce the loss of the motor. They are made by a new technology, hot press. The hot pressing process includes milling, hot pressing and hot deformation. Compared with common sintered materials, magnetic field oriented molding and sintering are not needed. This is due to the radial deformation of the material. They can be magnetized into multipole, deflected multipole and radial monopole (monopole magnet means that the magnet has only one pair of North and south poles).
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What are the advantages of radial ring magnets?

  • 1. Reduce a large number of assembly costs;
  • 2. High dimensional accuracy;
  • 3. Reduce the air gap of motor to improve power density;
  • 4. Reduce the pole number and the deflection angle of the cogging torque;
  • 5. The flux waveform can be controlled by rectangle to sine;
  • 6. Excellent temperature stability, corrosion resistance and time stability;
  • 7. Reduce motor noise.

Four advantages of multipolar sintered Nd-Fe-B ring magnet

  • 1. High flux density of sky;
  • 2. Realizing the high efficiency utilization of rare earth permanent magnet;
  • 3. Non magnetic material rotor shaft reduces motor weight without reducing magnet performance;
  • 4. Make motor design smaller and lighter.

Which motors can use multipole radial ring magnets?

Such as electric tools, synchronous motor, stepping motor, DC brush less motor, peripheral motor, spindle motor, steering control motor, etc.
Radial ring magnet size range?

  • D16 x D12 x H<15
  • D70 XD x h, wall thickness: 2-7mm, height < 50

Magnet grade: N35-N42, N35H-N42H, N35SH-N42SH, N33UH-N35UH
The angle of magnet of inclined magnet: the smaller the angle is less than 45 °, the easier it is to produce; the magnet in 45 ° direction is mainly used for driving system; and the motor adopts magnet of about 10 °.
Radial ring magnet will be the development trend of motor magnet in the future. However, even with proven technology, it can not replace traditional arc or bread motor magnets, why?

  • 1. Radial magnets are expensive because the cost of tools and coils is required in most cases.
  • 2. The bonded magnet with outer diameter less than 20 mm has greater comprehensive advantages.
  • 3. Due to the size limitation, some large diameter magnets can only be realized by segmented magnets.
  • 4. If there are too many magnets, radial rings are a good solution.
  • 5. If the magnet is quadrupole, it is best to assemble the arc magnet into a ring.

Sintered ferrite ring

Sintered ferrite magnetic ring can not only be magnetized in general (axial and radial one pair of poles), but also can be magnetized in multiple poles, that is, a plane or side of multiple poles, we call it multipole magnetic ring, because this product belongs to the sintering process, so it is also called sintered ferrite multipole magnetic ring.

Rubber ring magnet

Rubber is one of the ferrite magnetic material series. It is made of bonded ferrite powder and synthetic rubber through extrusion molding, calendering molding, injection molding and other processes. Flexible and twistable magnet. It can be processed into strips, rolls, flakes and various complex shapes. Rubber magnets are made of magnetic powder (SrO6Fe2O3), polyethylene (CPE) and other additives (EBSO, DOP), etc., and are manufactured by extrusion and calendering. The rubber magnetic material can be of the same sex or the opposite sex. It is made of ferrite magnetic powder, CPE and some trace elements, and can be bent, twisted and rolled. It can be used without more mechanical processing, and the shape can be trimmed to the required size. The rubber magnet can also be compounded with PVC, back glue, UV oil, etc. according to customer requirements. Its magnetic energy product is between 0.60 and 1.50 MGOe. Application areas of rubber magnetic materials: refrigerators, information signage racks, fasteners for fixing objects to metal bodies for advertising, etc., magnetic sheets for toys, teaching instruments, switches, and sensors. Mainly used in micro-motors, refrigerators, disinfection cabinets, kitchen cabinets, toys, stationery, advertising and other industries.

AlNiCo ring magnet

Aluminum Nickel Cobalt is the first permanent magnet material developed. It is an alloy composed of aluminum, nickel, cobalt, iron and other trace metal elements. According to different production processes, it is divided into sintered aluminum nickel cobalt (Sintered AlNiCo) and cast aluminum nickel cobalt (Cast AlNiCo). The product shapes are mostly round and square. The casting process can be processed into different sizes and shapes; compared with the casting process, sintered products are limited to small sizes, and the produced blanks have better dimensional tolerances than cast products, and their magnetic properties are slightly lower than cast products, but they can Workability is better. Among the permanent magnet materials, cast AlNiCo permanent magnets have the lowest reversible temperature coefficient, and the working temperature can be as high as 600℃. Alnico permanent magnet products are widely used in various instruments and other applications.

Samarium Cobalt ring magnet

SmCo ring magnet is divided into SmCo5 and Sm2Co17 according to the composition, which are the first and second generation rare earth permanent magnet materials respectively. Because its raw materials are very scarce and expensive, its development is restricted. Samarium cobalt (SmCo), as the second-generation rare earth permanent magnet, not only has a high magnetic energy product (14-28MGOe) and reliable coercivity, but also shows good temperature characteristics in the rare earth permanent magnet series. Compared with NdFeB, samarium cobalt is more suitable for working in high temperature environment (>200℃).

Magnetic field distribution of ring magnet

What is the magnetic field principle of ring magnet?
Ring magnet. The ring magnet made of hard magnetic material has no magnetism before magnetization. The position and number of magnetic poles depend on the way of magnetization. So the specific use, the number of poles depends on the customer.

What are the pole positions of common ring magnets?

Pole position:

  • 1. Some have one or more pairs of magnetic poles in the outer ring of the ring;
  • 2. Some have one or more pairs of magnetic poles in the inner ring of the ring;
  • 3. Some of them are on the top and bottom of the ring (one N, one S);
  • 4. Some magnetic poles are on a ring end face and have one or more pairs of magnetic poles.

The distribution map of the magnetic induction line of the circular magnet is also a hot topic for many netizens. The following section provides the distribution map of the magnetic induction line of the circular magnet for reference.
As mentioned earlier, the magnetic field distribution of the ring magnet is also related to your magnetization direction. The axial, radial, multipole and monopole magnetic field distribution will be different.

The distribution of magnetic induction line of ring magnet:

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Ring magnet uses

Ring magnets are widely used in scientific experiments, such as demonstrating magnetic repulsion force, passing magnetic rings through a wooden pole, when the same magnetic poles contact each other, they will not contact, as well as magnetic levitation, motor, electroacoustic, fishing, medicine, etc.

Production technology of ring magnet

The production process of ring magnet, generally speaking, is as follows: the materials are mixed and melted, and then the refined metal blocks are broken into small particles. Put the small particles into the mold and press them into shape. And then sintering. What is sintered is the blank. The shape is usually square or cylindrical. Take the square as an example, the size is generally concentrated in the length and width of 2 inches, and the thickness is about 1-1.5 inches. The thickness is the magnetization direction (high performance magnets are oriented, so they have magnetization direction). Then, according to the actual needs, the blank is cut into the required size and shape. Cut a good magnet, chamfering, cleaning, electroplating, magnetization, it can be.

Detailed introduction of the deep processing process and working procedure of sintered NdFeB magnet

The deep processing process of sintered NdFeB magnet is as follows:
Magnet blank – outer contour finishing – cutting – grinding – chamfering – electroplating – inspection, testing – finished products.

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  • The external profile finishing of magnet is usually completed by centerless grinder (cylindrical magnet) or surface grinder (square magnet), so that the blank magnet has a regular external profile and reaches the specified geometric size;
  • The cutting process is to use diamond internal slicer or wire cutting machine to cut the finished magnet into a shape and size close to the finished product;
  • The finishing grinding process is to use the surface grinder, double-sided grinder or other grinders to process the dimension and form and position tolerance of the magnet to the requirements of the finished product;
  • Chamfering is a pre-treatment process before electroplating. In order to reduce the uneven coating thickness caused by the relative concentration of current density on the edge of magnet in the electroplating process. Due to the small size and different shapes of sintered NdFeB magnets, the free rolling finishing process is most suitable for the mass chamfering of the products. Free rolling finishing technology includes vibration rolling finishing, eddy current rolling finishing, centrifugal rolling finishing and spindle rolling finishing. Among them, the vibration rolling finishing has been widely used by the deep processing factories of sintered Nd-Fe-B magnets for its high production efficiency and fast chamfering speed;
  • Electroplating is to form a protective layer on the surface of the magnet, which is usually realized by free barrel plating process. For larger magnets, hanging plating process is adopted. The coating of sintered Nd-Fe-B magnet can be divided into Ni plating, Zn plating, phosphating, electrophoresis, alloy plating, composite plating, etc. according to the use environment and appearance requirements of the magnet;
  • In addition to electroplating, physical vapor deposition (PVD) is also used as the surface protective layer of sintered NdFeB magnets. PVD can be divided into evaporation, sputtering and ion plating to form al, Zn and Cr coatings, while CVD can form nitride and carbide coatings of Ti and Cr. In addition, various kinds of surface protective coatings can be obtained by chemical passivation, electroless plating, hot dipping and thermal spraying;
  • The inspection and testing process is to test the dimension, form and position tolerance, appearance state, coating corrosion resistance, magnetic properties and other specified indicators of the finished magnet products.

Dimensional accuracy of ring magnet products

The dimension precision of NdFeB ring magnet is about (+ / -) 0.05mm. In fact, the existing processing means can reach the accuracy of (+ / -) 0.01. However, because NdFeB ring magnets generally need to be coated by electroplating, they need to be cleaned before electroplating. The corrosion resistance of this material is very poor, and the dimensional accuracy will be cleaned out in the pickling process. Therefore, the precision of a good electroplating product can not reach the level of cutting and grinding.

Orientation of ring magnets

Orientation: NdFeB ring magnets are oriented magnets. In short, the actual effect is that only the orientation direction of a square magnet has the highest magnetic field strength, and the other two directions have much lower magnetic field strength. When you draw several magnets together, the oriented magnets can only be drawn in one direction, not arbitrarily. The work of this orientation is carried out when the blank is pressed. This also limits the size of the magnet blank, especially the height of the magnetization direction (generally the working direction, that is, the direction of the NS pole). At present, the reasonable height of magnetization direction is generally no more than 35mm. High performance, generally no more than 30mm. So, what if you need a magnet with a large size in the direction of magnetization? You can stack several magnets together, and the effect is similar to the series connection in an electric field. Of course, this way in the actual use of little significance, the use of few.

How long does it take to produce ring neodymium magnets?

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  • First of all, it takes at least one day to prepare the raw materials and check whether they are qualified or not.
  • The second is drilling. The qualified blank is drilled with a punch. Metal drilling progress is slow, it takes 2 days. If it is a countersunk hole, then there is another process, that is, first straight hole and then countersink.
  • The third is slicing. After drilling, the blank is put into the slicer for slicing. It will take five days for 10000 magnets to be delivered without rush.
  • The fourth is chamfering. The cut black pieces are chamfered by chamfering machine (without chamfering, electroplating is impossible, or electroplating surface is easy to fall off). It will take one day
  • The fifth is electroplating. It takes 2 days for electroplating.
  • The sixth is magnetization and packaging, about one day.

That is to say, it takes 10-12 days for a normal disc magnet, 12-15 days for a disc punch, and 10-12 days for a square magnet to be formed by cutting three times.
I believe you have a certain understanding of the production cycle of the ring magnet after reading it. If you are a purchasing friend, I hope you don’t press too hard on the delivery date. If you are in a hurry, you will be in a mess. Give a delivery date acceptable to both parties.

Calculation formula of ring magnet weight

  • π * (a + b) (a-b) * C (thickness) * P (density) / 4000 (where a and B represent length and width respectively)

What are the precautions for the storage and transportation of magnets?

As a special product, how is the magnet transported? What should be paid attention to in transportation?
First of all, the storage of magnets, how do magnets store?
Pay attention to the humidity in the room. It must be maintained at a dry level. The temperature should not exceed room temperature; Black block or blank state of the product can be properly oiled (general oil can be); Electroplating products should be vacuum sealed or isolated from air storage, to ensure the corrosion resistance of the coating; Magnetized products should be sucked together and stored in boxes, so as not to suck up other metal bodies; The magnetized products shall be stored away from magnetic disks, magnetic cards, magnetic tapes, computer monitors, watches and other objects sensitive to magnetic fields.
How are the magnets transported? What should I pay attention to?

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There are two main problems in magnet transportation, one is how to protect the magnet, the other is how to prevent the damage of magnet magnetic field to the surrounding environment and personnel.
First of all, we must ensure that the environment in which the magnets are stored during transportation is dry. If the humidity is relatively high, it is easy to cause the magnets to rust. You can also use some anti rust oil on the surface of the magnet, which can prevent the magnet from rusting. For the magnet with electroplated coating, it should be transported in vacuum to prevent corrosion of electroplated coating.
In addition, the temperature of transportation must not be too high. Generally, demagnetization will occur when the magnet exceeds 80 degrees. Therefore, during transportation, try to keep it at room temperature. Secondly, in order to prevent collision between magnets during transportation, which may cause damage, it is better to separate magnets with wooden board. In the process of transportation, we must prevent the fierce collision. In the process of transportation, the operator should handle it with care.
Next, it is to solve the impact of magnetic field on the environment. First of all, try not to transport magnets together with computers, watches and other items sensitive to magnetic field. For the problem of how to shield the magnetic field, the simplest way is to wrap the magnet with iron sheet or carbon steel plate, and then arrange the magnetism of the magnet to form a good magnetic circuit inside. When choosing the means of transportation, maglev train and air transportation are good choices. However, the price will be higher. Moreover, if air transportation is carried out, the shielding of magnetic field will be more strict.

How can magnets be transported by air?

Often see netizens in the major forum post bar asked how to take a strong magnet on the plane, what measures need to be done? What are the requirements for packaging?
As the weak stray magnetic field interferes with the navigation system and control signal of the aircraft, the International Air Transport Association (IATA) lists magnetic goods as category 9 dangerous goods, which must be restricted during the collection and transportation. So now some of the air cargo with magnetic materials need magnetic detection, in order to ensure the normal flight of the aircraft. Magnetic materials, audio materials and other instruments containing magnetic accessories should be tested for magnetism.

Magnet air transport standard

According to the relevant provisions of iata902: if the maximum magnetic field intensity measured at 2.1m away from the measured object does not exceed 0.159a/m (200nt, i.e. 2mgs = 0.002gs), the article is not restricted as a magnetic material and can be treated as a general cargo.
If the maximum magnetic field intensity measured at 2.1m away from the object is more than 0.159a/m, but any magnetic field intensity measured at 4.6m away from the surface of the object is less than 0.418a/m, the goods can be collected and transported as dangerous goods.
If the magnetic field intensity at 4.6m away from the surface of the object is greater than 0.418a/m, then the object is not allowed to be transported by air.

How to meet the air transportation standard?

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In order to meet the above requirements of air transportation, it is necessary to demagnetize the magnets for air transportation. Although it is called demagnetization, it is not demagnetization of the magnets, but through special shielding packaging, so that the magnetism displayed on the package can meet the requirements of aviation safety transportation. Shielding packaging usually uses high magnetic conductivity materials, such as cold rolled sheet, galvanized sheet, etc. if the amount of magnetic materials is large, several layers should be packed. According to the principle of Faraday cage, after packaging, the magnetic field mainly circulates in the box, and there is little leakage. Outside the shielding package, the magnetic field is packed in cartons or wooden cases.

The packing of magnet in air transportation:

  • 1. The opposite magnetic poles of magnetron, illuminometer and other instruments and devices must be placed relatively.
  • 2. Permanent magnet materials must be equipped with magnetic armature or shielding to prevent compass instrument deviation caused by magnetic field.
  • 3. Each package of magnetic material must be correctly marked and labeled in accordance with Chapter 7 of IATA Dangerous Goods rules.
  • 4. Ensure that the magnetic field strength measured at 4.6 m (15 ft) from the surface of the package does not exceed 0.418 A / M (0.00525 Gauss) before shipment.
  • 5. It is suggested to pack large pieces in wooden cases.

Magnetic detection

The carrier of magnetic materials airlines or logistics companies will require customers to do magnetic testing, issued “air transport conditions identification report”, in order to ensure the normal flight of the aircraft. Generally, the air transportation appraisal can only be issued by a qualified professional appraisal company recognized by the Civil Aviation Administration of the country, and generally, samples need to be sent to the appraisal company for professional testing, and then the appraisal report needs to be issued. If it is not convenient to send samples, the professional personnel of the appraisal company shall conduct on-site testing, and then issue the appraisal report. The validity period of the appraisal report is generally used in this year, and it should be redone after the year.
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In magnetic testing, customers need to pack the goods according to the requirements of air transportation, and the testing will not damage the packaging of the goods. In principle, the testing does not open the box of the goods, but only tests the stray magnetic field on six sides of each goods. If the magnetic inspection of the goods is unqualified, special attention should be paid. First, with the consent of the customer, the magnetic inspection staff will be entrusted to open the box to check the goods, and then put forward relevant reasonable suggestions according to the specific situation. If the shielding can meet the requirements of air transportation, the goods shall be screened according to the client’s entrustment, and relevant fees shall be charged.
Understanding the magnetic field
In order to confirm the accuracy of the above contents, our company dialled the major mainstream logistics companies in the name of sending NdFeB high-intensity magnet, and obtained the following conclusions:
Send to China: mainstream logistics companies such as Shunfeng and Shentong do not accept air waybill for magnetic materials, they can only transport them by land; EMS, if the customer can issue “identification report of air transport conditions”, the express collector will determine whether they can receive them according to the situation.
Send abroad: EMS and SF will not accept the waybill of magnetic materials sent abroad (including Hong Kong, Macao and Taiwan), and will not accept the waybill no matter by land or air. DHL or UPS can be used overseas, but customers are required to do magnetic testing. Express companies can apply for testing business on behalf of DGM (different delivery places and testing institutions), and the cost is paid by customers.

Where can i buy ring magnets?

1. Trade Fair
One of the best places to find high quality rare earth ring magnet manufacturers from China is trade fair. You will have a chance to see what kind of rare earth ring magnets they can build and check process closely. At the same time, you can collect valuable information from face-to-face conversations with sales representatives, gain in-depth understanding of rare earth ring magnet company, and be able to compare various competitors immediately. According to where you are, I recommend some rare earth ring magnet exhibitions.

Of course, the budget of the trade show may be a headache.
2. Internet search

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Most suppliers of rare earth ring magnets in China have a good website (for example:, which is easy to find. Go to Google or social media, like LinkedIn, Facebook, etc. Checking their posts will give you a lot of information. Online forums are another place to exchange stories, ideas and experiences.
3. Proposal
Others in the permanent magnet industry may be willing to lead you to a leading supplier of rare earth ring magnets. Ask them to share their recommended manufacturers. Or you can tell people on the Internet what you’re looking for. You will contact several manufacturers of rare earth ring magnets, both offshore and overseas.

How to buy ferrite ring quickly and accurately?

Before purchasing ferrite magnetic rings, we should make clear the use of ferrite magnetic rings, such as the magnetic force does not need NdFeB magnets, which can resist infection, or be used for motors and sensors.
For example, purchasing ferrite magnetic ring is used for power supply internal, or wire, transformer, to know the performance index of ferrite magnetic ring, such as inductance, turn number, it is better to know the size of ferrite magnetic ring.
For example, if you buy ferrite magnetic rings for sound speakers, you need to know the size and performance of ferrite rings, and whether they need to be charged for delivery.
For example, to buy ferrite magnetic rings for DC motors or sensors, we should know the magnetization mode of the magnetic rings, whether it is multipole, tolerance, requirements for magnetic size, etc.
We provide ferrite magnetic rings with sintered ferrite magnetic rings, injection molded ferrite magnetic rings. If you have quotation, samples, and consultation questions, please contact us.

How to choose the specification and model of motor magnetic ring?

Everyone knows that the motor is made by the principle of electromagnetic induction, and the motor magnetic ring is an important part that affects the motor speed. The motor rotor determines the power and the quality of the performance of the motor. So how should we choose the motor magnetic ring? Let’s tell you how to choose the model of the motor magnetic ring. I hope it will help you.
How to choose the specifications and models of magnetic rings, there are often many customers who have just developed or just contacted how to choose the magnetic rings. Some problems about electromagnetic interference of electrical appliances and connecting wires are discussed, which lead to the failure of communication equipment. So how to choose the magnetic ring specification and model.
In the selection of injection molding magnetic rings, how large the wire is used, the inner hole must be noted, the line thickness and the inner hole of the magnetic ring must be just right, too big to penetrate, too small will leak magnetic field, and the injection mold should be slightly larger than the magnetic ring size, but do not gap too much, so that it is not easy to damage the mold during injection molding. If there is its frequency, the frequency is not up to, the line diameter is so large, then the outer diameter and inner hole are not changed, but the length should be selected a bit longer magnetic ring. Generally, the choice of magnetic ring has the priority of large outer diameter, small inner hole and long length. The more material the size of such ring is, the better.
The clip on type magnetic ring is how to select, clip on magnetic ring, compared with other magnetic ring models, is much better, easy to use, fast, it is made of two-piece magnetic core and plastic shell assembly, also known as the assembly type magnetic ring. Select such models, must be selected according to frequency, different frequencies choose different models. It can be directly buckled on the interference line without injection molding. In the case of large inner diameter, it can be repeatedly wound for 1-2 cycles, the more it is wound, the better the impedance effect.
The method of selecting flat magnetic ring, the inner hole of the flat magnetic ring is flat and wide, and the length and outer diameter of the ring appear flat, so it is called flat magnetic ring or flat magnetic ring. This type of model is generally used on the line arrangement. The selection is based on the width and thickness of the line. The width of the line and the flat magnetic ring must be consistent, and it does not meet the requirements of the thread, and it is too loose to meet its characteristics. Therefore, the lower line shall be measured with caliper first and then the selection shall be carried out.

The price of ring magnets

The price of ring magnet is composed of the cost of raw materials, slicing cost, hole punching fee, electroplating fee, magnetization and packaging fee. Among them, the cost of materials accounts for the largest proportion, so when customers purchase magnets, the general NdFeB manufacturers will recommend that customers choose the appropriate size and performance, which can save costs.
In terms of quality, there will be some irregular NdFeB manufacturers choose recycled materials and black leather materials to make products. In this way, the material cost will be greatly different, which is one of the main reasons for the difference in quotation of each magnet manufacturer.
In terms of product tolerance, many small magnet manufacturers do not have production quality inspectors, which will lead to the tolerance change of magnets.
On electroplating, some NdFeB manufacturers will send out a part of magnets to small electroplating plants for processing, so the cost will be very low, but the color and adhesion of the plating are very poor.
From the perspective of magnetization packaging, some NdFeB manufacturers do not choose magnets for saving work, and some products with missing side and corner are sent directly to customers, which are common problems.
Therefore, if you want to buy good quality, there are strict requirements for magnets, or suggest to visit the factory on the spot and choose a magnet manufacturer with good reputation, so it will be reassuring.

Is the price of high temperature resistant strong magnet higher than that of ordinary magnet?

Permanent magnet is divided into many kinds of magnets, including neodymium iron boron magnet, ferrite magnet, aluminum nickel cobalt magnet, etc. As far as the small edition knows, the temperature characteristics of various magnets are as follows:

  • Limit working temperature of neodymium iron boron (Curie temperature 312 ℃) 80-180 ℃
  • Strontium calcium ferrite (Curie temperature 450 ℃) limit working temperature 250 ℃
  • Samarium cobalt 1:5 (Curie temperature 750 ℃) limit working temperature 250 ℃
  • Samarium cobalt 2:17 (Curie temperature 825 ℃) limit working temperature 300 ℃
  • Aluminum nickel cobalt: (Curie temperature 860 ℃) limit working temperature 450 ℃
  • 1. Readers may not understand the limit operating temperature and Curie temperature. The so-called limit working temperature is that when the working temperature exceeds the limit temperature, the magnetic force will slowly drop. (at this time, the magnetic force is reversible, and when the temperature returns to normal state, then the magnetizer will be recharged immediately and then it will be revived in place immediately). Curie temperature refers to the rise of the magnet from the limit temperature or beyond the Curie temperature, and the magnetic force of the magnet is 0. (the magnetic force is irreversible at this time, even if the charger is used to fill the magnetic field, it will not be able to make up for it.)
  • 2. The conventional grades of NdFeB are n35-n52, n33m-n48m, n30h-n52h, n30sh-n45sh, n28uh-n38uh and n28eh-n38eh. The higher the number of the same series of brands, the higher the price, but the same stability resistance; the higher the price of different series brands and the same number, the higher the price in the future, and the stronger the temperature resistance, the stronger the performance; the market price of NdFeB blank materials is fluctuating, and it is really better than who is the price of which, the process cost of the current market and the factory should be combined.
  • 3. Samarium cobalt magnet and nd Fe-B magnet of the same performance size can be seen from the metal element ratio of the two above! The content of Fe in Nd Fe B is higher, and the content of rare earth elements is less, and the price of iron is very cheap. Therefore, the price of NdFeB is cheaper! The content of samarium and cobalt in samarium cobalt magnet accounts for about 70%, so the price is slightly higher, and the price is about twice as much as that of NdFeB.
  • 4. When it comes to the same performance (except for the temperature resistance), NdFeB has an absolute advantage over the aluminum nickel cobalt. According to the long history of the immersion magnet industry of small series, the price of aluminum nickel cobalt is more than twice as high as NdFeB.
  • In general, ignore the same performance. The higher the temperature resistance, the higher the price.

How to conduct long term business negotiation with Chinese rare earth ring magnet manufacturers

1. Contact your supplier
Once you have selected your injection tool supplier, contact them to start your first audit. If the budget allows, you can fly to China to better understand the manufacturing process of rare earth ring magnets. In addition, it allows you to inspect equipment to ensure that procedures and practices meet the standards you require. If it is difficult to transfer from the sales representative’s contact information to the factory visit, you can request an online audit to check their rare earth ring magnet manufacturing facilities and technology. Make sure that Chinese rare earth ring magnet manufacturing companies fully understand your inquiry sheet and have no problem in communication.
2. Negotiate preferential terms
As with any new business relationship, full due diligence must be carried out before entering into any agreements or remittances with suppliers of rare earth ring magnets in China. It’s better to start with a small one. If possible, negotiate preferential terms.

  • What are the shipping terms?
  • What are the terms of payment?
  • How much credit are they willing to provide?
  • How fast can they finish the project?

Browse through some hypothetical scenarios to see which terms apply to this situation. You don’t want to wait for an emergency.
3. Establish long term business relationship with rare earth ring magnet manufacturers in China
The key to ensure your production plan is to establish a solid cooperative relationship with your Chinese rare earth ring magnet supplier. The more history you have with them, the more loyal they see you, the more chips you have and the faster you turn around. You may get more favorable terms, negotiate flexible production plans, invest in future product development, or get preferential treatment. By adopting these strategies, it is easy to identify China’s rare earth ring magnet manufacturing partners and receive multiple offers within a few weeks of initial contact. These quotations should be based on a full understanding of our inquiry and save at least 35% from our current domestic production costs.
After reading this guide, I hope you can get a lot of information you need. If you are looking for a Chinese rare earth ring magnet manufacturer, or you want to know more about Chinese rare earth ring magnet manufacturers, we have many years of experience in rare earth ring magnets here. Please share your questions in the comments below or contact us. We are always at your service.

How to Verify a Chinese Ring Magnet Supplier Worthy of Long-Term Business

No matter where you are looking for suppliers, Google or some exhibitions, all good suppliers will have the following four characteristics:

a. The right balance between quality and price

20210320031630 52737 - How to buy ring magnets

You can always find cheap products in the market. But I bet you won’t buy from suppliers who are 15 percent cheaper than the industry’s lowest price. In business, you get what you pay. Adjust the budget on the premise of ensuring the quality of the products. The lowest price may be accompanied by poor quality and sometimes fraud.
A few days ago, a seller in South Korea sent us an inquiry for Nd-Fe-B ring magnets. We quoted him the price. But he thought it was very expensive, so he found a supplier and offered him a nd Fe-B ring magnet cheaper than ours. Three months later, we received his email saying he had purchased 200000 NdFeB ring magnets in total, but only 1800000 NdFeB ring magnets and some defective ones. He asked us for advice. I just want to say, don’t try to save a little money, and it’s a lot of loss.

b. Expertise of supplier sales personnel

I think a qualified salesman should be familiar with the products he sells. He knows its materials, the price differences between different materials, advantages and disadvantages, and the relevant certificates required for import and export. You ask a question, a good salesman will give you a variety of choices, let you choose the best, save your time. But a bad salesman may be hard to answer your question clearly.

c. Communication efficiency

Time is money, so effective communication is crucial. In international trade, communication relies mainly on e-mail. In some parts of the United States and the United States, the time difference is long, which may lead to slow response. This problem can be solved by using the common chat tool. Some Chinese suppliers may use WhatsApp or Skype, but they may not be able to view the information on time, and some do not use it at all.

20210320032313 20177 - How to buy ring magnets
I suggest you install a Chinese application like wechat on your phone. In Europe and America, not everyone uses Facebook to communicate, but in China, everyone uses wechat in their daily lives. They will reply to you at any time, even on weekends, Chinese people are working hard.

d. Responsibility – attitude to problems and Solutions

A responsible supplier treats all orders, regardless of size, equality. However, many suppliers are treating small orders (just reaching the minimum starting volume or below the minimum order volume) that they are only interested in doing one-time business with you. So they will give you a higher price and will not care about your order.
Buying existing brand products or customized products from China, especially a batch of products, from production to import to your country, may be a complex and time-consuming process. There are various challenges in the process, especially if you are importing from China for the first time. That’s why it’s more important to choose a responsible supplier.
Moreover, in the process of production, there will be some small challenges and obstacles. For example, the trademark is printed in the wrong location, or the required changes have not been changed, etc. Here, the key to ensuring everything goes well is the attitude of the supplier to deal with these issues. If a supplier escapes responsibility in case of a product problem or fails to compensate for the problem by solving the problem, he is certainly not a good supplier.
A good supplier understands the principle of win-win and is willing to take responsibility for his mistakes. He can make himself unprofitable because there are some unexpected problems, but he won’t let you suffer unreasonable losses. He will keep a positive attitude whether it is a large order or a small order because he wants to establish a long-term relationship with you.

How to Send Money to China for Lowest Cost?

When you need to pay to Chinese suppliers or travel agencies, you will doubt which payment method is the best way to solve the financial problem, so as to ensure safety and low processing cost.
China is also a country that strictly controls foreign exchange transactions. For any Chinese citizen, the maximum annual currency exchange limit is US $50000. How about US dollars or RMB? How to send the recipient in RMB?

Paypal (suitable for less than $500 payment )

How to transfer money to China by using PayPal?

PayPal is the most convenient way on a payment arrangement. It accepts debit card and credit card, so it’s easy to send money from any accounts of you.

And the process to send a PayPal payment is simple.

  •  You will need to register an account from
  •  Connect your Bank Card with PayPal.
  •  Ask your recipient to do so if they don’t have the PayPal account too.
  •  When both of your accounts are ready, you can send the payment then.

(P.S.: The PayPal account is in the format of the Email address.)

How much is the PayPal transfer fee?

PayPal has no handling charges for the sender and only charges handling fee for the beneficiary.

Please  check following transfer fee table of PayPal for easy reference (Based on the U.S. PayPal account sender):

Payment method: Country of recipient account: Fees (based on send amount)
$0.00-$49.99 USD $50.00-$99.99 USD $100.00+ USD
PayPal Cash/PayPal Cash + balance/a bank account linked to PayPal. Canada and Europe $0.99 USD $2.99 USD $2.99 USD
Any other country $0.99 USD $2.99 USD $4.99 USD
By a credit card, debit card or PayPal Credit. Canada/Europe $0.99 USD + 2.9% of the transaction amount + 0.3 USD $2.99 USD + 2.9% of the transaction + 0.3 USD $2.99 USD + 2.9% of the transaction amount + 0.3 USD
Any other country $0.99 USD + 2.9% of the transaction amount + 0.3 USD $2.99 USD + 2.9% of the transaction amount + 0.3 USD $4.99 USD + 2.9% of the transaction amount + 0.3 USD

Let’s take if you want to send USD 500 to China via PayPal (via debit card) for example, the handling fee is $4.99 + ($500×2.9%) + $0.3 = $19.79 USD.

Any tips to avoid PayPal transfer fee?

And PayPal offers a free transfer if both your account and recipient account are U.S. PayPal account, you can check the following screenshot from for reference.

pasted image 0 - How to buy ring magnets

But most of the Chinese suppliers create the PayPal account with a Chinese address when registering, and PayPal will also identify the country of the network IP visiting their website.

So a suggestion to lower down your PayPal transferring fee is to register PayPal account by your bank account rather than a credit/debit card. The bank account transfer is via bank ACH channel, and this system is hard to cheat. However, the debit card is easy to report a loss then stopping the money transferring to increase the risk for PayPal to charge an extra handling fee.

(* Fee cost from

How long is PayPal take to transfer money to China?

PayPal offers 2 different services when transferring money:

  • Standard Service: The fund will be transferred in 2 working days (meet postponement after 7:00 PM and weekend). Free of Charge.
  • Instant Service: The fund will be transferred within 30 mins — additional fee 1% of the amount and maximum charge USD 10.00.

In what amount makes PayPal fit for use to send money to China?

As PayPal accepts credit card payment, it is helpful when you are short of cash-flow for a higher amount of purchase.

However, PayPal provides 180 days of refund protection; the beneficiary will worry about cheating behavior. A cheater is easy to apply for a refund after the recipient provides courier information for a purchase.

So for Chinese suppliers, they prefer to receive a smaller amount (less than USD 500) from PayPal payment to reduce the risk of cheating loss, for more significant amount than USD 500, they probably will ask for other payment methods.

The Chinese beneficiary cannot directly use USD currency you transferred by PayPal. They will need to withdraw the USD (if you send in this currency) from PayPal and exchange to RMB. And PayPal is charging a high cost of USD 35.00 for every withdrawal, which also drives the recipients who don’t use PayPal frequently to reject the PayPal payment.

Western Union

(Trustpilot 7.9 points)

Western Union is a payment solution provider with a long history. They are trusted from 1871 and get a vast network of up to 500,000 agent locations.

How to transfer money to China by using Western Union?

Long ago, Western Union strictly required all of their transaction senders must present in one of their locations. After upgrading their service a lot of recent years, now you can make your payment through Online / In-Store / Mobile App, any way you can think of.

Anyway, they charge different handling fees for different sending ways. It seems that Western Union still has deep feelings for their counter operation, they charge a significantly lower fee for In-store than Online and Mobile App.

Operating a Western Union transfer is simple. The recipient even don’t need a banking account and they only need to provide information as below:

  •  Name: MU MU ZHANG (First Name: MU MU / Family Name: ZHANG)
  •  City: Ganzhou City
  •  Province: JiangXi Province
  •  Tel: 0086-130xxxxxxxx  

After you send the money, you will need to provide the following information to the recipient for collection:

  •  MTCN number: xxx-xxx-6789 (you will get it from Western Union system after made the transfer)
  •  Name of sender: Lucy Taylor
  •  actual amount: $5000
  •  beneficiary: MU MU ZHANG

If you transfer money to China, when the payment is made, and you provide all the information to your China recipients, they will take their ID card and go to one of WU agent locations in China, fill the form and get the cash.

How much is the Western Union transfer fee?

You can quickly check the handling fee of your transfer by price-estimator–Western Union official site.

And for easy comparison, we also work out several set handling fees as below for your quick reference, based on the method of sending to China & Online:

Send to China in Cash Online Order Online Order and Pay
and finish at a WU location (cheaper rate than direct In-store) by Bank Account
Remittance Amount Handling Transfer Handling Transfer
fee Time fee Time
500 5 USD in mins 25 USD 4 workdays
1000 7 USD in mins 26 USD 4 workdays
2000 8 USD in mins 36 USD 4 workdays
5000 15 USD in mins 65 USD 4 workdays

From the above comparison, sending cash is still more preferable by Western Union. And if you want to make the transfer by Debit card or Credit Card, PayPal rate is a better choice.
Meanwhile, Western Union allows to send money in minutes and by days, depends on the different rate of charge, for your selection. Also, it is a better way for the recipient to collect money by “Cash at WU location,” rather than to their bank account; otherwise it will charge a higher handling fee.

Any tips for ensuring the Western Union transfer is smooth?

Based on our experience, below are the points you need to pay attention when using Western Union to send money to China:

  • 1. Making sure the First Name and Family Name, which is essential for the success of a Western Union payment. Some customers cannot make the payment due to the mistake of the name.
  • 2. If you made something wrong on recipient information, go to WU location for correction.
  • 3. Western Union is not allowed for commercial purpose, do not show any business information on the transfer.
  • 4. One Chinese recipient (one person) can only receive no more than USD 50,000 (or equal value foreign currency) per year, please check with your recipient if they reach the quota.

Special notes when using Western Union to send money to China:

Western Union offers weak exchange rate as they also make money from it, so it is not recommended to arrange like send out USD but the recipient to get CNY in China, the exchange rate could be around 5% different than mid-market price.

When you send cash in a significant amount, the handling fee of Western Union will be much higher than Telegraphic Transfer service offered by the bank, so please compare the handling fee if you are sending an amount more than $5,000.

As Western Union also ask for high agent fee to their partner, lots of China banks have quit the cooperation with them, such as Agriculture Bank of China. So the WU agent location in China is rapidly decreasing from 2017, and the convenience for China recipient is no doubt being worse than before. Please check with your China supplier to make sure they are easy to make use of your WU payment first before you made it.

Telegraphic Transfer (T/T), Wire Transfer

Telegraphic Transfer (also known as Wire Transfer, Bank Transfer) is the most popular business to business payment method nowadays; it requires both sender and beneficiary to have a business Bank account for the transaction.

When you enter the bank to ask for an arrangement of Telegraphic Transfer to send money from the U.S. to China, they may tell you that what they offer is Wire Transfer. Don’t worry; they are the same thing. The Wire Transfer is a more official name for Telegraphic Transfer Payment. Wire Transfer is accomplished via the SWIFT system, and the SWIFT system is the only international channel you can send money to China bank account.

How to transfer money to China bank account by using T/T transfer?

When you are going to make the Wire Transfer, you need to know the following information  before you go to the bank:

  •  Beneficiary Name:
  •  Beneficiary Account:
  •  Bank Name:
  •  Bank Address:
  •  SWIFT Code:

And then you can fill the form in the Bank with the above information, and follow the bank instruction step by step to finish the process.

How much does it cost for sending by T/T transfer?

The handling fee for Telegraphic Transfer varies from different Bank. In our experience of working with thousands of buyers, we suggest making the transaction via a more prominent scale bank to ensure the transfer efficiency and reduce transfer fees. Bank charge is usually in the range of USD 20-50.

And it is recommended to leave the handling fee to be paid by the recipient. For order via T/T payment, there will be a higher charge which could be divided into two payments — deposit & balance. You can pay the 1st handling fee in balance, then the supplier will pay for another handling fee in deposit, so the supplier will feel fair to accept.

How long does T/T transfer take to China?

If you are making T/T from the U.S. to China, usually it takes 1-3 workdays for the money to arrive recipient’s account. If the money does not reach in time, you will need to check all the transaction information again to make sure there is no mistake.

Providing there are some problems in supplier account info, you need to ask your bank to cancel the transfer, and re-arrange transfer based on the correct information. Otherwise, the money would be blocked in the recipient bank side.

If you are sending money from European Countries to China, it will take 3-5 workdays. For people who are arranging from Southeast Asia countries like Malaysia and  Singapore to China, it only needs 1 day.

Special notes when using Telegraphic Transfer to send money to China:

  • 1. If you find your money still not reach the supplier that after 4-5 days, you will need to check the bank information again with the supplier and the bank. Providing there is a mistake in the information, go to your bank and ask for correction immediately.
  • 2. It is recommended to send wire transfer via more significant scale bank. They offer safer security for your money, and as they have a more substantial business scale in China, the handling charge and timing are also better.
  • 3. The SWIFT Code is the only correct code to send money to China. If the Bank asks you for Routing Number / BIC / IBAN, etc.,  you can conclude that this bank branch is not familiar with the wire transfer to China, try to find another more significant branch to ensure the smooth of your transaction.

SourceChina Permanent Magnet Manufacturer



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