Abstract
It is difficult to perform traditional machining of a permanent magnet, which is a functional material, because of its brittleness and magnetic forces. However, electrical discharge machining (EDM), which is a noncontact machining method, has been used for shape machining of magnetic materials. Magnetic materials have a Curie point; therefore, their magnetic flux density decreases when they are heated to a high temperature. Because EDM is a thermal process, it has the potential to control the magnetic flux density of a machined surface. In this study, to clarify the influence of magnetic flux density on a machined surface, the following machining conditions were investigated: the Duty Factor (D.F.) and internal temperature. The results showed that the influence of the magnetic flux density was small under low-energy machining conditions. In contrast, under high-energy machining conditions or a high D.F., the magnetic flux density significantly decreased compared with the initial value. These results have confirmed the importance of machining conditions for EDM of magnetic materials.
