Application of Permanent Magnet Materials and Excellent Performance of Electro Permanent Magnetic Milling Chuck


Solid magnetic material is also called permanent magnetic materials, because of high coercively force, it is generally stronger than 4000 a/m, after magnetize it to saturation by technology and remove the external magnetic field, it can still maintain strong magnetism for long time. The soft magnetic materials is generally less than 2800 a/m, the minimum reach to 500 a/m. Because of its coercive low power, technological magnetize to saturation and remove the external magnetic field, it is easy to lose magnetism. So the permanent magnetic material is much better than the soft magnetic material in performance. That’s why all the EPM milling chucks use permanent magnetic material rather soft magnetic material.

There are three kind of General permanent magnet materials: ferrite permanent magnet materials, rare earth cobalt permanent magnet materials, metal plastic permanent magnet materials.

1 The resistivity, coercive force of Ferrite permanent magnet materials is high, Curie point is low, the temperature coefficient of magnetic induction is big, magnetic energy product is not high.

2. Rare earth cobalt permanent magnet material has excellent magnetic properties, the maximum magnetic energy product is high, the residual magnetic induction intensity is also great, but the Curie point is slightly lower, the price is more expensive.

3. Metallic plastic permanent magnet materials, magnetic energy product, coercive force, the residual magnetic induction intensity is small, but it is easy to form, available to make complex parts, high strength, has a certain flexibility.

It generally adapts hard magnetic materials as the permanent magnet of electro permanent magnetic chuck, magnetism can kept strongly after the external magnetic field is removed, so it is very suitable to milling machining in CNC. And we also developed the electro permanent type for grinding.