Experimental Investigation on the Surface Formation Mechanism of NdFeB during Diamond Wire Sawing

Bin Wu; Zhenyu Zhang; Junyuan Feng; Fanning Meng; Shengzuo Wan; Xuye Zhuang; Li Li; Haoran Liu; Fuxu Zhang

doi:10.3390/ma16041521

Experimental Investigation on the Surface Formation Mechanism of NdFeB during Diamond Wire Sawing

Materials (Basel). 2023 Feb 11;16(4):1521. doi: 10.3390/ma16041521.

Authors

Bin Wu¹, Zhenyu Zhang¹, Junyuan Feng¹, Fanning Meng², Shengzuo Wan¹, Xuye Zhuang³, Li Li³, Haoran Liu⁴, Fuxu Zhang¹

Affiliations

¹ Key Laboratory for Precision and Non-Traditional Machining Technology of Ministry of Education, Dalian University of Technology, Dalian 116024, China.
² School of Mechanical Engineering, Hangzhou Dianzi University, Hangzhou 310018, China.
³ School of Mechanical Engineering, Shandong University of Technology, Zibo 255000, China.
⁴ Yantai Research Institute and Graduate School of Harbin Engineering University, Yantai 264006, China.

Abstract

Diamond wire sawing is widely used in processing NdFeB rare earth permanent magnets. However, it induces periodic saw marks and fracture chipping pits, which severely affect the flatness and surface quality of the products. In this study, the lateral motion of the diamond wire was monitored to determine the surface formation mechanism. Then, a white light interferometer and an SEM were used to observe the sawed surface profile. Finally, the surface quality was quantitatively studied by identifying the area rate of fracture chipping pits with an image recognition MATLAB script. According to the observation results, the calculation formula of PV which is related to the process parameters was deduced. Additionally, by combining the fracture rate and wire vibration, a novel method was proposed to investigate the optimal process parameters. It can be found that the surface quality sawed at P = 0.21 MPa, v_f = 0.2 mm/min, and v_s = 1.8 m/s remains better than when sawed at P = 0.15 MPa, v_f = 0.1 mm/min, and v_s = 1.8 m/s, which means the sawing efficiency can be doubled under such circumstances, i.e., when the surface quality remains the same.

Keywords: NdFeB; diamond wire sawing; saw marks; surface quality; swing; vibration.

Grants and funding

This research was funded by the National Key Research and Development Program of China (2018YFA0703400), the Young Scientists Fund of the National Natural Science Foundation of China (52205447), the Changjiang Scholars Program of the Chinese Ministry of Education, the Xinghai Science Funds for Distinguished Young Scholars at Dalian University of Technology, and the Collaborative Innovation Center of Major Machine Manufacturing in Liaoning.