Bonded ferrite magnets

The elements of ferrite magnet are ferric oxide/barium, strontium. Ferrite has higher coercive force and higher resistance to be demagnetized and oxidized than other non-rare earth permanent magnets. The biggest advantage of such magnet is their low cost. It is widely used from motors and loudspeaders to toys and craft etc.

Injection bonded ferrite magnets offer a combination of high magnetic strength and excellent physical properties. They offer large scale manufacture of shaped parts of close dimensional and magnetic tolerances. As smaller more efficient designs are therefore available then with increased design freedom lower losses of magnetism can be achieved.

Typical tolerances will depend largely on the part configuration and the type of tooling selected. Designers can consider standard tolerances of ±0.075mm. Tighter tolerances are available on request. Different binders are available including Nylon 6, 12, EEA and PPS. The material for any specification is chosen based on many factors for example temperature, strength, water absorption, solvent resistance, complexity of shape and compatibility with the magnet power.

The injection moulding process allows for moulding directly on, in or over other components thereby reducing secondary processing costs. This is called insert or overmoulding. Injection moulded magnets can be produced from very simple forms to quite complex arrangements in sizes up to 100gms. Further processing is rarely required but if necessary this can be achieved using conventional tools.