Compression bonded magnets are available using many isotropic neodymium iron boron material grades as well as crushed & powdered samarium cobalt materials. Combinations of different material grades may also be used to create specific magnetic characteristics. Compression bonded magnets offers higher magnetic strength than injection molded magnets due to their higher magnetic particle density, but are limited to simpler geometries. The epoxy binder used is resistant to normal industrial solvent and automotive fluids. To reduce corrosion of the rare earth magnetic materials, they are further coated with epoxy after shaping. The normal application temperatures range from below -40°C to above 165°C.

Compression bonding is most appropriate for relatively simple geometries due to limitations of the compaction process. The tooling costs for compression bonding is comparatively low, making it a better choice than injection molding where volumes are small. However, with modest automation, compression bonding can also be adopted for high volume manufacturing, with volumes upto millions of pieces per year.

Production Flow Chart for Compression Bonded NdFeB
Raw material (Mainly NdFeB powder and binder) preparation—Blending NdFeB powder and binder—Compaction molding—Machining—Surfacetreatment—Magnetizing—Final inspection—Packing—Warehousing

Production Flow Chart for Injection Bonded NdFeB
Raw material (Mainly NdFeB powder and binder) preparation—Blending NdFeB powder and binder—Injection molding—Machining—Surface treatment—Magnetizing—Final inspection—Packing—Warehousing

The performance of the compression bonded neodymium magnets.

The factory has over 15 years experience on manufacturing and technology on the plastic bonded magnets. With its own molding workshop, the factory can accomplish entire production process in-house from molding design, manufacturing and maintenance. The plant has obtained automatic production with rigorous Japanese-type management and precise equipments imported.