Bonded Magnets are formed by either injection molding or compression molding.
Injection molding provides flexible shapes and compression molding provides higher magnetic properties.
Injection Molded:
- Binder Types / Nylon / PPS / Polyamide.
- Temperature Range -40c – 180c
- Very Tight tolerances off tool ( 0.002 -0.003 Typical )
- Very good mechanical strength
Compression Bonded:
- Higher Magnetic Strength due to higher magnetic particle density.
- Epoxy Binder / Resistant to normal industrial solvents and automotive fluids
- Epoxy Coat after manufacturing to prevent oxidation
- Temperature Range -40c – 165c
- “Tight” tolerances off tool
- Good mechanical strength
Typical Bonded Magnet Applications:
- Sensors
- Brushless DC Motors
General Bonded Magnet Applications:
- Materials are isotropic and can be magnetized in any direction
- Wide range of existing tool sizes are available in rings, discs and rectangles
- Exsisting Multipole magnetizing fixtures for quick prototyping
- Easily machined
- Existing Multipole rings simplify assembly verse arc sepments
Surface Treatment:
In blending process, NdFeB alloy powder is embedded in epoxy resin or other thermal plastics what are solvent resistant against normal industrial and automotive fluids. Therefore bonded NdFeB magnet is more stable than sintered NdFeB magnet. However if the magnet is working in hot, moist and other corrosive environment, then coating is very necessary. Normally compression NdFeB magnet should have surface treated for protection purpose, meanwhile injection and calender bonded NdFeB magnet are no need to be coated due to high volume fraction of binder.
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