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Arc magnet manufacturers

Neodymium magnets are one of the most used magnets today. The application of these magnets is endless, especially with technological advancements. These magnets come in different types but the most commonly used ones are those which come in the shapes of a bar and an arc. Today, we’ll be talking about one of its types – arc magnets.

What are Arc Magnets?

First, we need to understand what neodymium magnets are. Neodymium is the fourth member of the lanthanide rare-earth element group. The periodic chart, it has the atomic number 60. Despite not naturally occurring in metallic form or unmixed with other lanthanides, neodymium is the 27th most abundant element in the Earth’s crust. They are the most well-known rare earth magnets and are composed of neodymium, boron, and iron alloy. Neodymium magnets are the strongest commercially available magnets and are the third generation of rare earth permanent magnets. Neodymium is especially antiferromagnetic and demonstrates magnetic properties in its pure form, but only at temperatures lower than 19 K (254.2 °C; 425.5 °F). They are ranked according to the output intensity of magnetic fields, demagnetization resistance, temperature coefficients, and the highest working temperature that is advised. In grading these, a stronger magnet would be indicated by a greater number. However, all neodymium magnets demonstrate extraordinary magnetism as compared to all other types of magnets, regardless of grading. Neodymium magnets are incredibly strong due to their high saturation magnetization and resistance to demagnetization. One of the key advantages of the NdFeB magnet is its ability to perform the same job with a smaller magnet than with a larger one. As a result, the overall size of the equipment may be reduced while the cost may also be dropped.

They are mostly used in the electronics, motor, and industrial industries. They are utilized in mobile phones, laptops, audio and visual systems, and hard disk drives in electronics. Motors and electric vehicles, as well as anti-lock brake systems, rely significantly on these magnets. They are utilized in the industrial sectors to make on-off buttons, magnetic separators, filters, generators, and even safety and security systems. Other applications for neodymium magnets include magnetic resonance imaging scanners, magnetic treatment, and dentures.

Neodymium arc magnets often referred to as Neodymium curved magnets, are a special type of sintered Neodymium magnet. The magnets are cylinder-shaped with a small curvature in the body, making them perfect for cylinder-shaped materials and pipework. Arc magnets have specific uses and are in some events customized to fit the purpose and demands of their uses.

Components and Differences Between ‘Normal’ Magnets

Because neodymium magnets are much stronger than ordinary magnets, employing neodymium arc magnets may generate more force and power in the things they occupy. The magnetic field generated by neodymium arc magnets is used to convert electrical currents into mechanical power. Curved magnets in either commonly used axial flux motors or radial flux motors can be altered into a skewed shape in order to reduce torque ripple, vibration, and noise caused by cogging torque. Eddy currents, which are electric current swirls caused by a changing magnetic field within a conductor (self-inductance), often cause demagnetization and a rise in temperature in the permanent magnet. This demagnetization and rise in temperature lower the motor’s operational efficiency. Laminated arc magnets, which are created by connecting many thin magnet pieces together, may significantly minimize eddy current loss while retaining the original structure and performance of the motor. Most times, the magnetization of arc magnets occurs through a diametrical direction and is almost always used with other pieces of arc magnets. Moreover, if an axial flux motor is being utilized, a specific amount of chord magnetized magnet should be inserted between conventional axially magnetized magnets to build a Halbach array. After, one should achieve more appropriate magnetic field strength and distribution for a certain axial flux motor.

The difference and applications between a normal bar-shaped neodymium magnet and a neodymium arc magnet are the high specificities an arc magnet has. As mentioned above, many factors can affect an arc magnet’s magnetization, use, and even fit to a machine. Because of this, it should be noted that pure radially magnetized neodymium arc magnets are extremely difficult to manufacture.

Where are they used?

Nearly all permanent magnet (PM) motors, generators, and magnetic coupling devices employ neodymium arc magnets for the rotor and stator. The formula of the magnet drives electrical currents, making them ideal for use in other dairy products such as power tools, refrigerators, and washing machines.

Neodymium arc magnets are also heavily used as motor magnets in the great majority of cases. Furthermore, the shape and structure of the magnet have a great influence on motor performance in addition to the magnetic performance and surface protective treatment. Avoiding cogging torque, which is brought on by the interaction of the magnet and the stator teeth, is difficult for slotted motors. Arc magnets are highly used in motors because of many reasons. Neodymium arc magnets have high remanence, high speed, large output torque, and high power. Because of this, the motor where the magnets are being used will have higher efficiency. Other than that, neodymium arc magnets also have high normal coercivity. Therefore, the motor’s functioning point is quite near its maximal magnetic energy. The thermal coefficient of coercive force is also relatively high in these magnets. Hence, a motor utilizing neodymium arc magnet/s will have good resistance to overload, demagnetization, anti-aging, and low-temperature resistance. Because of these properties, motors have improved working efficiency and have larger magnetic energy. Other properties include smaller dynamic loss, smaller losses in eddy current, and good temperature stability even in high temperatures. These are due to a superior curve of rectangularity of demagnetization, a better resistivity of permanent ferrite, and a small temperature coefficient. Arc magnets can also be used to make clutch-like assemblies known as magnetic couplings. The magnets generate a smooth force that is utilized to transfer or regulate mechanical power, therefore powering the object. Magnetic power is represented in liquid pumps and propeller systems by a physical barrier between the marine and non-marine atmospheres, eliminating the need for draft seals, which degrade fast due to these components.

How are they manufactured?

Neodymium arc magnets are always machined from blank due to technological limits in the magnetic field orientation molding process. As mentioned above, arc magnets have high specificity for their applications. To avoid any misunderstanding of the dimensions and positions, clients must sometimes provide a clear drawing with detailed specifications, tolerance and additional requirements if any. Other factors to specify include their inner and outer radius, and diameter. circumference, thickness, angle, length, etc. Hence, engineering drawing is important and necessary for the production of arc-shaped magnets. Manufacturing these magnets requires high levels of knowledge and skill. On top of that, they also require unique and special machinery because of the strong magnetism that neodymium magnets hold.

Manufacturing these magnets takes many steps. Most of the time these steps are:

  1. Proportioning
  2. Smelting
  3. Crushing
  4. Pulverizing
  5. Magnetic shaping
  6. Isostatic pressing
  7. Vacuum sintering and tempering
  8. Wire cutting and other processing
  9. Electroplating
  10. Magnetizing

Curved magnets are often machined via wire-cutting or copy grinding. Wire-cutting is well-suited to the machining of special-shaped magnets, but it is also criticized for its low production efficiency and high processing costs. Copy grinding, on the other hand, offers a competitive edge in terms of efficiency and cost but falls short in terms of dimensional application. Magnet producers should use machining techniques that are appropriate for the form, dimension, material utilization ratio, production efficiency, and processing cost.

After arc magnets are manufactured, they can be installed in different ways for magnetizing. One is where the arc magnet is magnetized individually, then inserted into the shell, and finally assembled as a whole. Another way is where the arc magnet is already incorporated and glued into the shell. It is ten magnetized and then assembled as a whole. A third way is having the arc magnet incorporated and glued, but assembled first and then magnetized. These installations canstill vary greatly but most depend on the process of gluing, assembling, and applying the magnetization.

Where can we find suppliers?

Neodymium arc magnets are very accessible nowadays. But, it is best to seek manufacturers and suppliers who are knowledgeable on the matter. As mentioned, arc magnets have specific designs and purposes. A manufacturer/supplier who is able to understand where the magnet shall be used and is able to explain other requirements should be a top consideration. Apart from that, one should also consider the shipping/transportation and accessibility requirements of the magnets. Requesting and buying specially designed magnets may come with many certificates and processes, so it would be better if the manufacturer/seller is also experienced with deals and has a good history with transactions.

ROBO Magnetic sells different types of magnets and has a proficient level of understanding and skill about magnets. You may inquire through /+86-574-88790219.


Article by

ROBO Magnetic Product Team

We are the manufacturer with 16 years of experience in custom neodymium magnets.

Need A Quote? Get in touch with us directly.

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