 Injection molded hard ferrite magnets are available using ferrite and blends of magnetic material to achieve an extensive range of properties. They are composite material consisting of hard ferrite powder (BaO.6Fe2O3 or SrO.6Fe2O3) dispersed in an engineering thermoplastic matrix. Polymer binders utilized by the Plastiform Division include nylons 6 and 12 and PPS (polyphenylene sulfide). Binder evaluations are a continuous activity in the Development Laboratory, in an effort to improve physical strength, maximum recommended use temperature, the application operating temperature is above 120℃ for nylons 6 and 12, and PPS can be useed up to 200℃.
Another benefit of the injection molding process is that magnet material can be directly molded into, onto, or against other assembly components eliminating subsequent assembly steps. This is called insert injection molding.
Injection molded magnets can be of very simple shapes or very complex. All or only part of the device may be magnetized. It is sometimes cost advantageous to make an entire part out of the magnet material and just magnetize the portion requiring magnetic output.
An important characteristic of injection molded magnets is that they conform dimensionally to the mold cavity which is precisely machined, the result being close tolerances in the finished product. What little dimensional variability there is results from shrinkage of the polymer during cooling. This depends upon part thickness and shape. Typical tolerances are +/-0.003 in/in. Closer tolerances on critical dimensions can be negotiated
Injection molded hard ferrite magnets can be manufactured with either isotropic or anisotropic material.The maximum Energy product (BH)Max for isotropic injection ferrite is up to 6.0 KJ/m^3 while for anisotropic 13.0KJ/m^3. Injection magnets are mainly used on micro motors and sensors. |
| magnetic properties sheet & Manufacturing processing flow chart |
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| Temperature dependence demagnetization curve |
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