In addition to regular shape with moderate size, sintered rare earth magnet is hard to directly achieve required shape and dimensional accuracy at one time due to the technical limitations in the magnetic field orientation pressing process, thereby, machining is an unavoidable process to the sintered magnet. As a typical cermet material, sintered rare earth magnet is considerable hard and brittle, then there are merely cutting, drilling, and grinding can be applicable to its machining process among conventional machining technology. Blade cutting typically utilize diamond coated or CBN coated blade. Different blade thickness and cutting edge position correspond to distinct notch depth and geometric tolerance requirements. Wire cutting and laser cutting are well suited to the machining of special shaped magnet, but accused of low production efficiency and high processing cost in the meanwhile. Drilling process of sintered magnet is primarily adopted diamond and laser. It is necessary to select trepanning process when the inner hole of the ring magnet larger than 4mm. As the by-product in trepanning process, trepanned core can be used for manufacturing other suitable smaller magnet and thus significantly enhance material utilization ratio. Grinding wheel for grinding process can be classified into metal-based and resin-based. Grinding wheel for copy grinding is produced on the basis of the grinding surface.
Bonded magnet is able to reach near net-shape manufacturing, thus exhibit superior material utilization ratio, very small processing volume and losses. Injection molded magnets are nearly free of subsequent machining and need only fix injection molding gate and flashes. For compression molded magnet, accuracy of dimension and geometric tolerance in pressing surface is guaranteed by tooling, especially ring magnet. Its height direction regularly processed a grinding process to fulfill higher accuracy.