Classification and characteristics of NdFeB magnets: It can be divided into bonded NdFeB and sintered NdFeB. Bonding is actually injection molding, while sintering is vacuum and heating at high temperatures!
NdFeB magnets are by far the strongest permanent magnets. Material grades are N35-N52; Various shapes can be processed according to specific requirements: round, square, perforated, magnetic tile, magnetic rod, convex, trapezoidal, etc.; Despite these advantages, the surface is prone to rust, so it usually needs to do some protective surface treatment: nickel plating, galvanizing plating, gold plating, epoxy plating, etc.
The applicable ambient temperature of ordinary NdFeB magnets is below 80 degrees, but there are several that can withstand high temperatures of 200 degrees. Mainly used in electronic appliances, packaging, motors, toys and automotive machinery.
How do magnet manufacturers process magnets and what are the processing techniques
The main raw material for the production of NdFeB magnets
The main raw materials are rare earth metal neodymium, rare earth metal fault, pure iron, aluminum, ferroboroalloy and other rare earth raw materials.
Production process
The production process of NdFeB magnets, in layman's terms, is this: the materials are mixed and smelted, and then the smelted metal blocks are broken into small particles. The small particles are put into the mold and pressed into shape, and then sintered out, which is the blank. The shape is generally square or cylindrical. Taking the block as an example, the size is generally concentrated in length and width of 2 inches, thickness of about 1-1.5 inches, thickness.
It is the magnetization direction (high-performance magnets are oriented, so there is a magnetization direction). Then, according to the actual needs, the blank is cut to the required size and shape. Cut magnet, chamfer, after cleaning, plating, magnetizing, and that's it.
Processing technology:
There are basically two types: slicer cut or wire cut.
The microtome is to cut the diamond inner hole cutting blade with a thickness of about 0.3mm, and cut the magnet to the required size according to the requirements. But this method is only suitable for simple square shapes and cylindrical shapes. Since it is cut by an inner hole, the size of the magnet cannot be too large, otherwise it cannot be placed in the blade. Another method is wire cutting. Generally used to cut tiles, and large size products.
Punching: small holes, generally drilled with vibrating diamond grinding wheel drill bits. Large holes, using the way of sleeve holes, which can save material costs.
Dimensional accuracy of NdFeB products
The dimensional accuracy of the product, which is relatively economical, is around ( +/- ) 0.05mm. In fact, the existing processing methods can fully achieve the accuracy of ( +/- ) 0.01. However, electroplating is generally required, and cleaning is required before plating. The corrosion resistance of this material is very poor, and the pickling process will clean away the dimensional accuracy. Therefore, a truly electroplated product. The accuracy is not at the level of pure cutting and grinding operations.
orientation
NdFeB is an oriented magnet. Simply put, the actual effect is that a square magnet has the largest magnetic field strength only in the orientation direction, and the magnetic field strength in the other two directions is much smaller. When you suck several magnets together, the oriented touching iron can only be sucked in one direction, and cannot be sucked together arbitrarily. The work of this orientation is carried out when the blank is pressed.
This reason also limits the size of the magnet blank, especially the height of the magnetization direction (-generally the working direction, that is, the direction of the NS pole). At present, the more reasonable height size of the magnetization direction is generally not more than 35mm. High performance, generally not more than 30mm.
In this way, what if you need a magnet with a large size in the direction of magnetization? You can superimpose several magnets, this effect is similar to the series connection in the electric field. Of course, this way has little meaning in actual use, and it is rarely used.
