Study on Polishing Method Using Double Magnet System by Superconductive Assisted Machining Method

Abstract Superconductive Assisted Machining Method (SUAM) has been studied for polishing methods inside the hollow structure such as SUS tube. Levitation tool with Nd permanent magnet in the SUAM system is trapped by magnetic flux pinning effect into the superconductor bulk mounted in the liquid nitrogen box. In this case, initial displacement of the levitation tool can be adjusted until 12mm during cooling process under magnetic field. Movement of the superconductor bulk controls the applied force and rotation speed of the levitation tool. In previous research, we demonstrated that the SUAM could be applied lapping and polishing process on concave and flat shapes of the resin, aluminum and SUS materials. In present study, we develop the double magnet system that Nd permanent magnet fixed under the superconductor to increase holding force of the levitation tools. As results, holding force and levitation amount of the double magnet system increase against the conventional single magnet system. We also evaluate dominant parameters such as the placement of the superconductors and magnet flux density distribution from double permanent magnets on the holding force and levitation amount. In this case, the holding force and floating amount is calculated by JMAG using Finite Element Method to compare with the experimental results.