Special Shaped Magnets

Due to the technological limitation of magnetic field orientation process, sintered magnet is difficult to achieve the shape and dimensions of practical application at once, therefore, machining process of blank is inevitable. Chinese magnet manufactures fully learned the processing superiority from ceramic and crystal industry, then taken processing levels to extremes. Rare earth permanent magnets made by powder metallurgy are typically hard and brittle cermet material, there are only cutting, punching and grinding can be utilized to the machining process of the rare earth permanent magnet among conventional processing technology. What about special shaped magnet?

▲ About Special Shaped Magnets

Special shaped magnet has irregular shape and mainly serve to specific demands. With the development of consumer electronics to the functional complexity and miniaturization, permanent magnet which often works as a key component is also required to adopt this trend. Irregular shaped magnets are mainly limited to special Neodymium magnets and special Samarium Cobalt SmCo magnets. The machining process of irregular shaped magnet is much more complex than conventional shape magnet. Thus often requires combining several different processing technology.

▲ New update in 2021: Laser Cutting

Besides lower processing efficiency, internal stress caused by conventional machining technology will generate a certain impact on microstructure and magnetic properties of sintered magnet. Ultrathin sintered Neodymium magnets in magnetic wireless charging devices have been experiencing an explosive growth from 2020. Magnet manufacturers tried every means to enhance capacity and cost performance, then laser cutting developed rapidly under this opportunity. Laser machining is to cut or weld workpiece by high power laser. For laser cutting, it has the merit of no contact, cutting force, and deformation in comparison with other frequently-used process technologies. In addition, laser cutting also has superior machining efficiency, accuracy, and quality. Laser cutting is relatively simple to use which need only to import cad drawings into equipment. Laser cutting has become a new selection to machine special shaped magnet with thinner thickness.

▲ Product Classifications of Special Shaped Magnets

● Special Shaped Neodymium Magnets

Special shaped magnets refer specially to the magnets with irregular shape which primarily serve for specific demands. Injection molded magnets are ideally suited for special shaped magnets, but maximum energy product (BH) max of routine isotropic injection NdFeB molded magnets are limited to 60kJ/m3 which cannot satisfy most of special shaped demands. Sintered magnets are generally difficult to satisfy net shape directly owing to technology limitations in production process, thus machining process is essentially impossible to be avoided. Therefore, sintered Neodymium magnets are always criticized by its machinability but special shaped Neodymium magnet still can be achieved via grinding or wire cutting process, hence its cost and production time are inevitability and significantly higher than conventional block magnets, bar magnets, ring magnets, disc magnets, rod magnets, arc magnets, countersunk magnets, and sphere magnets. Chinese Neodymium magnets  manufacturers have already formed a clear division of labor over the years, thus processing enterprises fully learned processing experience from crystal industry and always trying to introduce the latest processing technology. With the process of functional complexity and miniaturization accelerates, consumer electronics exist large demand for special shaped Neodymium magnet. Laser cutting has become a new selection to machine special shaped Neodymium magnet with thinner thickness.

● Special Shaped SmCo Magnets

Sintered magnets are produced via powder metallurgy process and generally criticized by their machinability, especially sintered Samarium Cobalt magnets. Sintered SmCo magnets can be classified into 1:5 type Samarium Cobalt magnets and 2:17 Samarium Cobalt type magnets base on the alloy composition, then 1:5 type and 2:17 type are also known as the first generation and second generation of rare earth permanent magnets, respectively. 1:5 type SmCo magnets have relatively better mechanical properties and malleability compared with 2:17 type SmCo magnets, then more easily to process SmCo micro magnet, thin-wall ring SmCo magnets, and special shaped SmCo magnet. Sintered SmCo magnets are still playing an irreplaceable role in higher temperature and high temperature stability areas which sintered Neodymium magnets are not possible. Then miniaturization and functional complexity process of some certain application also generates large demands for special shaped SmCo magnet. 

---The End---