Superconductive assisted machining (SUAM) is a novel machining method that eliminates tool interference via magnetic levitation tools. In our study, we developed a double magnet system (DMS) to increase the maximum power of the holding force and stabilize the magnetic rotation during polishing via the higher magnetic flux compared to a single magnet system (SMS). The maximum magnetic flux density of the DMS was approximately 100 mT higher than that of the SMS. In these cases, the entire holding force increases as the distance between the superconducting bulk and lower magnet decreases. The attractive forces are maximum around a displacement of 6 mm, although the repulsive and restoring forces increase spontaneously. The polishing performances of the DMS on the SUS304 and A1100P plates were evaluated using water-based diamond slurries, for equal levitation amounts. The amount removed by the DMS increased for the A1100P and SUS304 substrates compared to that by the SMS. In this case, we observe that the deviation of the polishing area on the DMS decreases compared to that of the SMS, reflecting a more stable rotation and movement due to the higher holding force.

1. [1] M. Sudo, “Advanced Control Technologies for 5-Axis Machining,” Int. J. Automation Technol., Vol.1, No.2, pp. 108-112, 2007.
2. [2] L. Silva, H. Yoshioka, H. Shinno, and J. Zhu, “Tool Orientation Angle Optimization for a Multi-Axis Robotic Milling System,” Int. J. Automation Technol., Vol.13, No.5, pp. 574-582, 2019.
3. [3] T. Suzuki, K. Yoshikawa, T. Hirogaki, E. Aoyama, and T. Ikegami, “Improved Method for Synchronizing Motion Accuracy of Linear and Rotary Axes Under Constant Feed Speed Vector at End Milling Point – Investigation of Motion Error Under NC-Commanded Motion –,” Int. J. Automation Technol., Vol.13, No.5, pp. 679-690, 2019.
4. [4] T. Saiki, M. Tsutsumi, H. Suzuki, M. Kouya, and M. Ushio, “Development of Measurement for Motion Accuracy of 5 Axis NC Machine Tool,” Int. J. Automation Technol., Vol.2, No.2, pp. 111-118, 2008.
5. [5] Y. Tanaka, K. Suzuki et al., “Study on polishing technology using magnetic levitation tools with superconductivity,” J. of the Japan Society for Abrasive Technology, Vol.62, No.4, 2018.
6. [6] H. Nakashima, K. Suzuki et al., “Study on Polishing Method using Magnetic Levitation Tool in Superconductive-Assisted Machining,” Int. J. Automation Technol., Vol.15, No.2, pp. 234-242, 2021.
7. [7] K. Suzuki, T. Nakasaki et al., “Study on polishing method using double magnet system by superconductive assisted machining method,” Proc. of Leading Edge Manufacturing/Materials & Processing (LEM&P2020), 8553, 2020.
8. [8] A. I. Larkin and Y. N. Ovchinnikov, “Pinning in Type II Superconductors,” J. of Low Temperature Physics, Vol.34, No.3-4, pp. 409-428, 1979.
9. [9] J. Bardeen, L. N. Cooper, and J. R. Schrieffer, “Theory of Superconductivity,” Physical Review, Vol.108, No.5, pp. 1175-1204, 1957.
10. [10] M. Tinkham and C. J. Lobb, “Physical Properties of the New Superconductors,” Solid State Physics, Vol.42, pp. 91-134, 1989.
11. [11] H. B. Radousky, “A Review of the Superconducting and Normal State Properties of Y1-xPrxBa2Cu3O7,” J. of Materials Research, Vol.7, No.7, pp. 1917-1955, 1992.
12. [12] M. K. Wu et al., “Superconductivity at 93 K in a New Mixed-Phase Yb-Ba-Cu-O Compound System at Ambient Pressure,” Physical Review Letters, Vol.58, No.9, pp. 908-910, 1987.
13. [13] D. He et al., “Spatial and temporal flux-trapping properties of bulk high temperature superconductors under static magnetization fields,” J. Supercond. Nov. Magn., Vol.28, pp. 2385-2391, 2015.
14. [14] J. R. Hull, “Superconducting Bearings,” Superconductor Science and Technology, Vol.13, No.2, pp. R1-R15, 2000.
15. [15] Y. Arai, H. Seino, and K. Nagashima, “Levitation Properties of Superconducting Magnetic Bearings using Superconducting Coils and Bulk Superconductors,” Superconductor Science and Technology, Vol.23, No.11, 115011, 2010.
16. [16] J. Wang et al., “The First Man-Loading High Temperature Superconducting Maglev Test Vehicle in the World,” Physica C: Superconductivity and its Applications, Vol.378-381, Part 1, pp. 809-814, 2002.
17. [17] L. Schultz et al., “Superconductively Levitated Transport System-the SupraTrans Project,” IEEE Trans. on Applied Superconductivity, Vol.15, No.2, pp. 2301-2305, 2005.
18. [18] L. Rossi, “The LHC superconducting magnets,” Proc. of the 2003 Particle Accelerator Conf., Portland, OR, Vol.1, pp. 141-145, doi: 10.1109/PAC.2003.1288863, 2003.
19. [19] Y. Hiramatsu et al., “Evaluation of Magnetic Cutting and Polishing with Superconducting Bulks,” J. of Physics: Conf. Series, Vol.871, 012048, 2017.
20. [20] N. Yamachi, T. Nishikawa, N. Sakai, K. Sawa, and M. Murakami, “Levitation forces of bulk superconductors in varying fields,” Physica C: Superconductivity, Vol.392-396, Part 1, pp. 579-584, 2003.