China Neodymium And Ferrite Magnets Manufacturer & Supplier 
Hall magnet ring is a kind of special and Hall components (sensors) together with the use of magnets, usually made of permanent magnet material, because the shape of the magnet is very often the shape of the ring, so it is also known as the Hall magnet ring, but also can be other shapes, today this article to answer the concern of the users of the Hall magnet ring whether you need to open the mold of the problem.
Hall sensor magnetic ring commonly used materials are ferrite and neodymium iron boron, the magnetic ring is designed into multiple pairs of poles (even pairs), such as 2 pairs of poles, 3 pairs of poles or 4 pairs of poles, etc., and each pair of poles contains two magnetic poles, N (North Pole) and S (South Pole). The magnetic ring rotates with the object to be detected (e.g., motor rotor) to form a time-varying magnetic field.
Whether or not you need to open a mold depends on the material, size, and number of magnetization poles you need.
Such as commonly used ferrite materials, such as sintered and injection molded ferrite, are required to produce molds, multi-pole magnetization but also have the corresponding magnetizing jig, but if the magnet supplier has this mold, then do not need to open the mold. Ordinary sintered NdFeB magnetic rings can be produced without molds, but injection molded NdFeB processing requires molds.
Developing a mold for a magnet ring requires some investment and time costs. If the expected volume production is large and the required size is not conventional, developing a mold may be an economically sound choice. However, if the volume of production is not large or a quick start-up is required, it may be more economical to consider existing close-to-size magnetic rings.
Our company is a professional supplier of magnetic rings for motors and sensors, we have many multi-pole ferrite rings and multi-pole neodymium rings, maybe we have what you are looking for.
Hall sensor magnet recommendations;
Hall plastic magnetic ferrite ring 8 poles 15 x 6 x 4.9 mm
Hall sensor 6 pole plastic magnet countersunk ring 8.5 x 2 x 4 mm
Injection molded magnetic ring with small hole 9.5mm x 1mm x 2mm
22 pole radial injection molded neodymium magnet ring Φ14mm
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