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How are neodymium magnets magnetized?

Rare earth magnets include neodymium magnets. Because they are permanent magnets, they may endure a very long time indeed. It is the most widely used rare earth magnet and is composed of an alloy of neodymium, boron, and iron. Commercially accessible, it is the strongest permanent neodymium magnet and is inexpensive for the typical individual.

To help you make an educated selection for your next project, we at ROBO Magnetic feel it is crucial to understand our neodymium magnets’ physics and share this information with you. To achieve the highest possible strength, neodymium magnets are shaped so that their magnetization points in a specified direction. To better understand the significance of magnetic direction, let’s take a closer look!

What Is Magnetizing?

A high magnetic field must be applied to a magnet to turn it into a neodymium magnet. The magnetic domain structure is restructured, and the neodymium magnet retains its magnetization when this field is applied (Br). Isotropic magnetization means that the remanent magnetization is aligned with the magnetic field. On the other hand, an anisotropic neodymium magnet can only be magnetized in the direction of its anisotropy.

A brief current pulse is sent via a conductor or coil to magnetize. A magnetization machine, a strong capacitor, and a controller generate the brief pulse. The duration of the current pulse required for various materials varies. A material’s resistivity may be used to forecast how the magnetic pulse would appear. A very resistive material may need a few microseconds of magnetization, whereas more conductors may need many hundred microseconds to be magnetized. A neodymium magnet’s volume is an important factor in the current pulse’s duration.

Eddy Currents are generated in an electrically conducting substance during the magnetizing process. This creates a magnetic field in the opposite direction of what is applied.

In addition to variable pulse durations, different materials need diverse magnetic field strengths. Material coercive force determines the magnetic field strength required for magnetization, an inherent characteristic of the material. Standard inductors, i.e., solenoids, may provide axial and diametrical magnetization. Radial, multiple-pole, or any other complicated magnetization, on the other hand, must be performed in a magnetization fixture specifically designed for that purpose.

Methods of Magnetizing Neodymium Magnets

To “magnetize” is to “increase the magnetism of a magnet with inadequate magnetism” or “magnetize” a magnetic material. Direct current is sent via a magnetized coil when an item is positioned in its magnetic field. As a result, there are several methods for magnetization. Our manufacturing employs pulse magnetization for efficient magnetization.

Pulse magnetization is based on the notion of creating a brief, intense magnetic field by pulsing a current through a coil. Permanent magnets with strong coercivity or multi-pole magnetization may benefit from this technique. Various permanent magnets, including neodymium, may be magnetized using this device, which is extensively utilized in manufacturing and using permanent magnet materials. In terms of efficiency and dependability, it’s an excellent choice. It’s easy to use and has no specific power needs, so it’s perfect for construction sites of all sizes.

The following are the stages in the magnetization process:

  1. Our operators will check whether the electroplated neodymium magnets are complete before magnetizing. Unqualified faults, such as an unfinished magnet form or an uneven coating, will be eliminated from neodymium magnets.
  2. We can determine whether a spacer is required for a neodymium magnet based on its size and grade, or we may work with the client to develop bespoke spacers based on their specific needs.
  3. N and S poles are labeled to differentiate them for specific customers’ needs.
  4. Our magnetizers will pay close attention to the magnetization axis while doing their work.
  5. Each magnet will be tested for magnetic flux by our operators after the magnetization process. There are two ways to ensure that the neodymium magnets are saturated and that the magnetization orientation is proper.

Magnetizing Direction

The first stage in obtaining magnetism in permanent magnet materials like neodymium magnet is determining the direction of magnetization. Neodymium magnets and magnetic assemblies may be identified by their north and south poles. The crystal structure of permanent magnets is the primary source of their magnetic characteristics. For example, an external magnetic field may greatly enhance the magnet’s magnetic characteristics, and these qualities will not be lost when the magnetic field is removed.

The following are possible directions for magnetization:

Axial Magnetization Direction

The neodymium magnet’s axial magnetization is oriented perpendicular to its axis. Axially magnetized magnets have their magnetic field oriented on an axis. It’s the most common sort of magnetization out there. Axial magnetization in a cylindrical magnet means that the magnet’s magnetic poles are on a flat surface. To put it another way, if you want a neodymium magnet to be more effective, it should be magnetized in this direction.

Diametrical Magnetization Direction

Diametric magnetization occurs along the neodymium magnet’s length or diameter, while axial magnetization occurs along its length. If the neodymium magnet is cylindrical, the poles are located on the curved side of the neodymium magnet. Neodymium magnets are more effective when their curved side is close to the substance they’re designed to attract.

Radial Magnetization Direction

Radial magnetization is a kind of magnetization in which the neodymium magnet’s magnetic field is focused on its outer and inner diameters. For ring-shaped neodymium magnets, it is often utilized.

Common Magnetizing Direction

Disc or cylinder neodymium magnet

The axial magnetization of neodymium discs places the poles on the circular surface by default. Diametrical magnetization is a term used to describe the magnetism that runs perpendicular to the diameter of certain of our neodymium disc magnets.

Ring neodymium magnet

One of the poles (N or S) is on the outer surface of the neodymium magnet, while the other is on the inner lateral surface, which is why rings are magnetic. Large-scale production is required since each unique magnetization device must be custom-built for each specific size and kind.

Arc neodymium magnet

It is possible to magnetize the arc neodymium magnet in four different orientations.

  • The magnetization direction is in the thickness
  • The magnetization direction is tangent
  • The outer arc is N pole
  • The outer arc is an S pole

Multi-pole Magnetization

Multi-pole magnetization necessitates using specialized magnetization heads with prepared windings to generate the requisite magnetic field dispersion.

What Kind Of Adverse Situations Will Be Encountered During Magnetization?

  1. Magnetization faces the wrong way. In this case, N and S pole magnetization directions have been provided in the incorrect spot. We make neodymium magnets this way to maximize their strength. To make neodymium magnets as powerful as possible, we would have to make them so they can be magnetized in any direction.
  2. Another problem occurs when the magnetization is not completely saturated. Consequently, the neodymium magnet cannot provide the requisite magnetic field strength due to its low strength and poor magnetization. The neodymium magnet may not be as powerful as predicted if the magnetization is not saturated.

What Is Saturation Magnetization?

An object’s magnetization reaches its maximum saturation point when this value is reached. Because of the possibility of domain walls shifting and magnetization rotating inside individual domains as the external magnetic field intensifies, a magnetic body’s interior is generally split into any number of domains (single-domain state). This stage is known as magnetization saturation. The magnetization value at this period is known as saturation magnetization if the simple magnetization axis and the external magnetic field direction match.

The Principle Of Magnetization Unsaturated.

Because saturation is an internal phenomenon, measuring the amount of saturation in material might be difficult. But several first-order procedures may signal saturation. It’s possible to look at the non-working face of the workpiece (the face that isn’t being used) and see whether any magnetic fields are “leaking” through. Indicators of saturation, such as leakage, point to the need for a thicker workpiece. Alternatively, you may try increasing the thickness of the workpiece and see what happens. A noticeable increase in attractive force may be obtained by increasing the thickness of the workpiece by a factor of two. However, the initial workpiece was already saturated at that time. A workpiece’s cost, mass, and simplicity of manufacture will all be impacted if its thickness is increased.

Magnetic efficiency may be reduced by saturation, which can have a detrimental effect on design.

The limit of a material’s ability to transmit magnetic flux is said to be “saturation.” Using a pipe analogy works well since there is a limit to the amount of material that a pipe can transport and a limit to the magnetic field that a substance can convey.

The amount of induced magnetism that a substance may have is finite. A material is considered saturated when no more internal magnetism can be generated inside it.

The material’s magnetic properties and the strength and direction of the applied magnetic field all have a role in the fluid saturation state.

Saturation effects thinner pieces more than thicker ones.

The effective, attractive force between a neodymium magnet and a workpiece is reduced due to not completely magnetic saturation in the workpiece.

Note on Magnetization

  1. Forced air, water, and low-temperature stable cooling are only a few cooling options available throughout the magnetization process. This will help to avoid the effect of temperature that directly affect saturation.
  2. When the magnetizer’s capacitor is functioning, the peak pulse current is very high, and the capacitor’s current performance requirements to survive the impact is extremely high.
  3. Magnetizing power supply efficiency, stability, and high precision are critical in manufacturing. Similarly, the machine measures the magnetic flux of the permanent neodymium magnet material once it has been magnetized.
  4. When the peak value of the pulsed magnetic field exceeds 3 to 5 times the coercive force (Hc) of the magnetized material in the magnetizing coil, saturable magnetization is performed. An instantaneous magnetic field of more than 30,000 may be formed by pairing it with an appropriate magnetizing coil. The magnetizing effect is greater for high coercivity neodymium magnets.
  5. Coil’s horizontal center and neodymium magnet’s horizontal center are the optimal places to place the neodymium magnets.
  6. If you use a magnetizer, ensure the voltage repeatability is good and the capacitance is steady. Capacitors made of foil currently have the best stability.

Conclusion

It is our aim that this article will help you better comprehend magnetization and its many processes. If you’re interested in learning more about neodymium magnets, we suggest you check out ROBO Magnetic page for more information.

Since 2006, ROBO Magnetic has been engaged in magnets’ research, development, production, and distribution. Neodymium magnets are just a few of the high-quality permanent neodymium magnets available from this supplier.

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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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