Radially oriented anisotropic NdFeB ring magnets
MPCO has developed a unique hot extrusion process to produce Radially oriented anisotropic NdFeB ring magnets.
Unlike sintering, this process does not rely on a magnetic field for radial orientation.
Our process starts with raw material powders manufactured by rapid quenching of the prescribed alloys into nanocrystalline flakes.
These flakes are hot pressed to the theoretical density and then hot extruded to ring-shaped magnets.
During this advanced hot extrusion process, randomly oriented crystal grains go through preferential grain growth and rotation.
This results in the full-density, nanocrystalline structure with the highest level of radial orientation.
Although the basic magnetic properties (Br, Hc, and (BH)max) are similar to sintered NdFeB, our unique process gives rise to several remarkable features listed below.
Features of Radially oriented anisotropic NdFeB ring magnets
Highest energy product of 240 ～ 400 kJ/m3 (30 ～ 40 MGOe) in truly radial direction.
Full rings with a wide range of diameters (min. OD 6 mm -) and lengths (max. 80 mm) for easy assembly.
Various magnetization patterns possible (multi-pole to uni-pole, various skew angles) by the design of magnetizing fixtures.
Precise magnetization waveform control (such as rectangular, trapezoidal, sinusoidal) for high power or low cogging.
High heat resistant grades (up to 180 deg.C) available.
Inherently better corrosion resistance due to the absence of internal porosity.
Applications of Radially oriented anisotropic NdFeB ring magnets
– EPS (Electric Power Steering) motors: Combined with controlled magnetization waveforms, Radially oriented anisotropic NdFeB ring magnets can realize quiet and smooth rotation, giving rise to a natural feeling of steering an automobile.
Servomotors: High power and low cogging, quiet and smooth rotation, ideal for AC/DC servomotors used in industrial robots requiring quick and accurate movements.
Manufacturing process of Radially oriented anisotropic NdFeB ring magnets
Realizing close theoritical density and high radial orientation ratio by hot extrusion technology keeping miro structure of grain size.