【 What kind of magnets are used in micro motors? 】 At present, most motor manufacturers use neodymium iron boron magnets for motor magnets and motor magnets. A few motor manufacturers also use samarium cobalt magnets and permanent magnet ferrites for motor magnets.
1. Samarium cobalt is resistant to high temperatures (400℃), has a bright metallic color, and is relatively expensive. Considering all factors, micro-dots rarely use samarium cobalt.
2. Ferrite permanent magnets are undoubtedly better than neodymium iron boron magnets in terms of high temperature resistance (around 400℃). However, to make ferrite magnets compatible with micro-motors and achieve precision, the manufacturing process is very expensive, and the scrap rate is also very high because they are prone to breakage or wear and chipping.
3. Permanent magnet motors using neodymium iron boron (NdFeB) magnets are small in size, lightweight, have a high torque-to-inertia ratio, high servo system response, high power and speed/weight ratio, high starting torque, and save electricity. Motor magnets are mostly tile-shaped, ring-shaped, or trapezoidal, and can be used in various motors, such as permanent magnet motors, AC motors, DC motors, linear motors, and brushless motors.
The following section introduces neodymium iron boron.
(1) People usually use the attraction and repulsion of magnets to drive, and generally choose radially symmetrical magnetized tile-shaped magnets to form a ring. Sintered neodymium iron boron is an anisotropic material and cannot be molded into the slightly complex magnetization direction desired by the customer in one step.
(2) Neodymium iron boron (NdFeB) magnets are also divided into sintered NdFeB and bonded NdFeB, with bonded NdFeB being more widely recognized in the industry. Currently, some manufacturers can also produce radial magnetization of bonded NdFeB magnets, but there are many requirements for size and grade (surface magnetic strength), and the magnetic properties also have process requirements for stability and consistency. At the same time, the mold coils and magnetization fixtures are very expensive. Unless it is a supplier with stable quality, very few manufacturers will choose bonded NdFeB. However, if your company is a manufacturer of high-quality micro motors, then bonded NdFeB is definitely your first choice for various types of magnets.
