NdFeB magnets are manufactured in the 4 following forms:
Sintered - fine NdFeB powder is compacted in a die and then sintered, fusing the powder into a solid material. There are 2 forms of pressing: die pressing (which involves a hard die into which the powder is placed and then pressed), and isostatic pressing (involving a special "rubber" die into which powder is placed and then pressed with equal force in all directions on the powder). Die pressed parts are usually made smaller than isostatically pressed parts. Although the magnetic properties of isostatically pressed parts are higher, the uniformity of magnetic characteristics is usually lower than that of die pressed parts. Sintered parts normally need some finish machining in order to meet final tolerances.
Compression Bonded - this is a technique whereby a special form of NdFeB powder is blended with a plastic carrier material, die pressed and then heated. Parts made in this way can be of complex shapes and come off the tool with close tolerances, requiring no further finish machining. They have lower energy products than sintered materials - in the range of 10 MGOe. The Bonded NdFeB materials are isotropic - i.e. they can be magnetized in any direction.
Injection Molded - NdFeB powder is blended with a plastic material and injection molded. The resulting parts have energy products in the 5 MGOe range, but can be made with extremely intricate shapes.
Extruded - though not popular at present, NdFeB based flexible magnets can be made by binding NdFeB powder with a carrier material and extruding the material in sheet or strip form. Energy products up to about 6 MGOe have been achieved in this way.