In daily production, there are generally three production processes for NdFeB magnets, namely sintering process, bonding process and injection molding process.
The sintered NdFeB magnet process is to grind the magnetic material into powder through air flow, and then put it into a smelting furnace to melt it into a whole material with specified specifications. The NdFeB magnets produced by this process have very high coercive force, and their magnetic energy product is more than ten times that of ordinary ferrites.
The price of NdFeB produced by this process has a certain standard and will not differ too much.
After it is produced and formed, it can be cut into products of different shapes as needed, but its surface has high chemical activity, so it must be electroplated on the surface, and zinc-nickel plating is commonly used.
Compared with the finished NdFeB process and sintering process, the price of bonded NdFeB is higher, mainly because it is integrally formed, completed in one process, and no other cutting process is required. It is a permanent magnet made by adding NdFeB powder and mixing it with some other materials through compression, extrusion or injection molding technology.
The injection molding technology of NdFeB magnets is the most demanding of all processes. The NdFeB produced by this process is expensive. It requires extremely fine and precise molds to put NdFeB powder into it to make finished products with complex shapes. Most of the finished products are very thin.
The surface of sintered NdFeB permanent magnets is generally required to be smooth and reach a certain precision, and the surface of the magnets delivered in blanks needs to be surface ground.
Common grinding methods for square NdFeB permanent magnet alloys are:
Flat grinding, two end surface grinding, inner circle grinding, outer circle grinding, etc.
Coreless grinding and double-head flat grinding are commonly used for cylindrical magnets.
Multi-station grinders are used for tile magnets, fan-shaped magnets, and anisotropic magnets.
