Pulse EPM Electro-Permanent Magnet Pulse EPM is composed of magnetic yoke, AlNiCo steel, excitation coils, magnetic poles& NdFeB magnets, and excitation coil works as a switch to change the working status.
Attraction principle Feed excitation coil 3 with a pulse positive current when EFM attracting billets, then a magnetic field occurs in it, which makes inner AlNiCo magnet 2 magnetized, and magnetic fields of AlNiCo magnet 2 & NdFeB magnet 5 are accumulated together, magnetic force line layout diagram is shown as below (figure 1). The magnetic field starts from N poles of AlNiCo magnet 2 & NdFeB magnet 5, then penetrates billet 6 and magnetic yoke 1 (or polar magnets), gets back to S poles separately, billet will be attracted firmly finally.
Release principle Feed excitation coil 3 with a pulse reversed current when EFM releasing billets, a reversed magnetic field generates in it, which makes polarity of AlNiCo magnet 2 reversed. And magnetic fields of AlNiCo magnet 2&NdFeB 5 cancelled out in the magnet, its magnetic force line layout diagram is shown as the following figure 2. Magnetic force line will form a closed loop, no magnetic force penetrate the billet and the magnetic force is approximately closed to 0, so that billet will be released.