Performance evaluation of superconductive-assisted machining (SUAM) with superconducting tapes

Dec. 1 11:30-11:45

*Shinya Iwasaki1, Hiroya Ishii1, Yushi Kinoshita1, Soji. E Otabe1, Kentaro Matsuo1, Tatsuya Nakasaki1, Keisuke Suzuki1
Kyushu Institute of Technology, Japan1

There are two types of hollow processing technology, one that processes before molding and the other that processes after molding. However, in hollow processing after molding, it is difficult to internally process an object which has a complicated shape. Therefore, SUAM (Superconductive-Assisted Machine) has been proposed in which a magnetic material is levitated to process an object by utilizing the magnetic flux pinning phenomenon of superconductors. In this study, we evaluated a new type of SUAM using double permanent magnets and superconducting tapes to obtain stronger repulsive force.

As shown in Fig. 1, the model of the SUAM has six superconducting tapes placed azimuthal at equal intervals from the center. Then, four layers similar to the upper layer of superconducting tapes were prepared under the superconducting tapes with the distances between the upper and lower layers at intervals of 100 mm. Then two permanent magnets were used. One was magnetized at the magnetizing position of 10 mm above the superconducting tapes. The other permanent magnet was magnetized at the magnetizing position of 1 mm bottom the superconducting tapes. Two permanent magnets are placed in a state of repulsion as shown in Fig. 1. And the repulsive force from the superconducting tapes to the permanent magnet magnetized at the magnetizing position of 10 mm above the superconducting tapes was calculated by using finite element method (FEM), when the permanent magnet was approached perpendicularly to the superconducting tapes. Then, the distance between the permanent magnet and the superconducting tapes was changed from 10 mm to 1 mm, i.e. the upper permanent magnet is approached to the superconducting tapes. Fig. 2 shows the FEM calculation results for a SUAM with double permanent magnets and a SUAM with single permanent magnet only at the above of the superconducting tapes. The results show that when there are double permanent magnets, the repulsive force is much greater than when there is single permanent magnet. This is because a repulsive force is generated between the permanent magnets by placing a permanent magnet with different magnetic poles under the top permanent magnet. Therefore, larger repulsive force by two permanent magnets and stable levitation by the superconducting tapes are achieved.

Keywords: Double permanent Magnet, SUAM(Superconductive-Assisted Machine)