How is a magnet magnetized?

Magnets that are created from particular earth elements such as neodymium magnets, before their magnetic energy is activated, are first mined, melted, ground, pressed, and sintered. During pressing, the particles in the magnets are aligned to give them a designated direction or pole. However, it is during magnetization that the magnets are given their magnetism and, until that happens, these demagnetized magnets are often referred to as bullets.

The process in which a magnet is magnetized begins with the activation of the properties of these bullets. This is done through a device called a magnetizer, which is equipped with a coil wire and an electric current that, when switched on, emits an external magnetic field and thus activates the magnetism in the bullets.

Methods of magnetizing a magnet

A magnet is magnetized using two methods: static magnetization and pulse magnetization. The former generally creates smaller magnetic fields, while the latter is generally used for stronger magnetization.

The method of magnetization is determined by various characteristics of the magnet, such as material, strength, and shape. Sometimes, manufacturers and others who handle magnets in an industrial environment may want magnets without magnetization for the following six reasons:

  1. For workers, it may be difficult, impossible, or dangerous, to assemble the desired product if a magnet is magnetized in the factory, due to its attraction to steel parts or attraction/repulsion with other magnets.

  2. In shipping, permanently magnetized magnets can affect, damage, or even destroy other items such as packages, bank records, credit cards, and watches, among others.

  3. Large, permanently magnetized magnets can damage or crush the body parts of people moving the goods.

  4. If a magnet is magnetized in the factory, it can affect navigational instruments, especially on aircraft, when moved, which is why laws govern the shipment of magnetized magnets.

  5. Magnetized magnets can pick up magnetically permeable dirt, which is present almost everywhere. This dirt is often in the form of very small, long, pointed needles, which rotate vertically towards the surface due to the action of the magnetic field. They are very difficult to see, and if they get into the hands of handlers, they act like splinters that are painful and difficult to locate and remove. This magnetic dirt, once on the magnet, is very difficult to clean, as it will simply move around a cleaning cloth.

  6. Manufacturers often need to control the magnetization process due to factors other than full magnetization, such as the effects of the magnetic pattern on the "grip". In some cases, this effect is desirable, such as for magnetic clutches, but often it is detrimental, causing inefficiency, noise, and vibration.

In addition, to complete magnetization, some other magnetization operations are often necessary, so measurements must be made to ensure that the magnetized magnets meet the requirements of their intended use. In other cases, mistakes are sometimes made in magnetization, handling, or assembly, which lead to demagnetization of the magnet.

Anyone might think that magnets are naturally magnetic, but it is interesting to discover that nowadays a magnet is carefully and professionally magnetized, from the coatings and shape to its magnetic properties.

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