Magnetic Circuit Design Principle of Electro Permanent Magnetic Chuck

Dec 18th 2024

EPM(Electro permanent magnetic) chuck magnetic circuit design usually uses two different magnetic materials as the main magnet, one for the high coercivity of the permanent magnetic material (such as NeFeB) as the main magnet, and the other for the medium coercivity of the magnetic steel material (such as cobalt-nickel-aluminium, etc.) as a reversible magnet, utilize the two kinds of magnetic yoke between the two kinds of magnets (generally for the No. 45 steel) to form a magnetic circuit, and then by the excitation of the coil of pulsed current generated by the electromagnetic field, change the direction of the magnetic field of the reversible magnet, to achieve the control and conversion of the internal magnetic circuit, so as to achieve the external demagnetization (DEMAG) or magnetisation (MAG), the specific work process as shown in the picture.

When the excitation coil is positively excited, the polarity direction of the reversible magnet is shown in picture. a, then the main magnet and the reversible magnet have flux outflow, through the external workpiece constitutes the external path, the permanent magnet suction cup is in the state of magnetisation: when the excitation coil is negatively excited, the polarity direction of the reversible magnet is reversed, as shown in Fig. b, the main magnet and the reversible magnet constitutes the internal path, there is no flux outflow to the outside world, and no flux passes through the external workpiece, so it is in the state of non-magnetisation, the electronically-controlled permanent magnet sucker is in the state of non-magnetisation. The magnet is in a non-magnetic state, and the electronically controlled permanent magnet suction cup is in a demagnetised state.