Bonded magnets appeared in the 1970s. At that time, SmCo had reached commercialization. The market for sintered NdFeB permanent magnets is very good, but it is difficult to precisely process into special shapes, and cracks, breakages, edges and corners loss are likely to occur during processing, and they are not easy to assemble, which restricts its application. In order to solve this problem, the permanent magnet is crushed and mixed with plastic, and then molded in a magnetic field. This is probably the most primitive manufacturing method for bonded magnets. Bonded ndfeb magnets are widely used due to the advantages of low cost, high dimensional accuracy, large freedom of shape, good mechanical strength, and light weight. The following are its main application products.
Ⅰ. Digital product hard disk drive magnets (HDD)-this is currently the largest application field of bonded ndfeb magnets
Ⅱ. Transmission motors for printers of office OA products, motors for scanners, synchronous feed motors for copiers (STP), magnetic rollers for laser printers, etc.
Ⅲ. Automotive motors and magnetic sensor products include EPS power steering sensor magnets, wiper motors, window shutter motors, seat adjuster motors, etc.
Ⅳ. Other types of industrial and household motors mainly include various types of servo motors, motors for electric tools, air-conditioning and refrigeration motors, etc.
Due to the huge difference in magnetic properties and molding, the use of bonded ndfeb magnets and sintered NdFeB magnets does not have a big overlap. Bonded ndfeb magnets are mainly used in the fields of hard disk optical drive spindle motors and low-power micro-special motors, while sintered NdFeb magnets are more used in fields such as high-power drive motors.