The magnetism of sintered NdFeb material mainly comes from its crystal texture which is easy to be magnetized, it can obtain extremely high magnetism under the action of external strong magnetic field, and its magnetism will not disappear after the disappearance of external magnetic field, so magnetization is the key step to obtain the magnetism of sintered NdFeB material. In the production and preparation of sintered NdFeB materials, magnetization is the last step before the finished product is delivered, but in the magnetic powder pressure into the blank has decided the NdFeB blank magnetic field orientation, the direction of the coming magnetization.

Magnetic field orientation

Magnetic materials are divided into isotropic and anisotropic magnets. The magnetic properties of isotropic magnets are the same in all directions and can be attracted together arbitrarily; the magnetic properties of an anisotropic magnets vary in different directions, the direction in which the best magnetic properties can be obtained is called the magnetic field orientation. A block sintered NdFeB magnet has the strongest magnetic field only in the orientation direction, and much less in the other two directions.

Magnetic materials in the production process of orientation process is anisotropic magnets, sintered NdFeB is generally used magnetic field orientation molding pressing, so it is anisotropy, so before production needs to determine the orientation direction, the upcoming magnetization direction. Powder magnetic field orientation is one of the key technologies for manufacturing high performance NdFeB.(bonded NdFeB is isotropic and anisotropic.

Directions and methods of magnetization

Magnetization is the process of applying magnetic field to the sintered NdFeB permanent magnet along the direction of magnetic field orientation and  gradually increasing the magnetic field intensity to reach the technical  saturation state.

Generally, sintered NdFeB has block, cylinder, ring and segment, and other forms, and then we will talk about their respective magnetization direction.

                                                           In addition to the ordinary single-pole magnetization, the sintered NdFeB also can be magnetized according to the actual needs of the multi-pole, that is, after the magnetization in a plane can appear multiple N, S poles. Due to the special design of the specification size and pole head of the magnetizing fixtures, there will be additional magnetizing fixture costs.

Magnetizing machine is a tool for magnetizing and magnetizing magnets of magnetic materials or magnetic devices. If the magnetized magnetic field can’t reach the technical saturation magnetic field, the Br and Hcj of the permanent magnet can’t reach their due values.

Then how to determine the energy of a magnetizing machine? Firstly the size and size of magnetization tooling are determined according to the size and magnetization direction of the magnet for the magnetized product, then calculate the size of the magnetic field in the center of the tooling, the size of the tooling’s magnetic field should be 3-5 times the coercivity of the magnet, after that the magnetization current is calculated,the capacity of the energy storage capacitor of the magnetization machine is determined according to the current and the voltage of the magnetization, and the energy of the magnetization machine is finally determined.

The basic principle of magnetization is to magnetize magnetic objects by placing them in a magnetic field formed by a coil of direct current, there are mainly direct current magnetization and pulse magnetization, technical details will discuss later.