The rare earth bar magnet is the solid cylinder shape. It combine the neodymium magnet high magnetic performance and thin geometry shape. It is suitable used in the thin instanllation space, drill hole, axle, outer cover and other diameter limited component. From the geometry view, the rare earth bar magnet is defined as the magnet whose length is bigger than the diameter cylinderical magnet. It belongs to the cylinder magnet. The magnet whose axle size is less than the diameter in the smaller cylinderical magnet is called the round disc magnet. The difference for the cylinder magnet and round disc magnet is geometry. It is not relevant to the material or the producing technology. Normally we define the cylinerical magnet by diameter and length. The L/D will influence the magnetization direction, magnetic performance and machanical operation and integrated approach between the magnet and its sorrounding components.
The Magnetization Direction
The normal magnetization direction is lengthwise direction. When the magnet is under the axial magnetization, the north and south pole are in the different sides of the magnet. The magnetic output focuse on the two sides of the magnet. It is suitable in the pole to pole attraction and the components which one or two poles interacted with steel or other magnets. The bar magnet is magnetized along the diameter direction. When we using the radial magnetization, the magnetic poles are in the two sides of the cylinder surface. It could make the magnet output the magnetic energy from side. It could be used in the location structure which need covey the magnetic energy along with the circumference.
The L/D will influence the magnetic performace of the magnet along with the axial magnetization. Normally, the L/D is bigger, the Pc is bigger. The work point is better. However, there are some other factor which could influence the magnetic energy. The magnetic pole area, air gap, magnetic grade, magnetic circuit and relevant steel component all could influence the magnetic energy. Only increasing the length could not increase the L/D.
