Eventos Anais de eventos
COBEM 2023
27th International Congress of Mechanical Engineering
Manufacturing of micro-scale Nd-Fe-B magnets by diamond wire sawing and electropolishing processes
Submission Author:
Erick Cardoso Costa , SC
Co-Authors:
Natalie Souza Heinz, Erick Cardoso Costa, Fabio Antonio Xavier
Presenter: Erick Cardoso Costa
doi://10.26678/ABCM.COBEM2023.COB2023-0042
Abstract
Nd-Fe-B based permanent magnets play a very important role for a wide range of industrial, military and consumer devices. Among the various processes applied for the production of permanent magnets are included the machining processes that are responsible for ensuring dimensional and shape accuracy, surface integrity quality, and ensuring tight tolerances. However, in the scientific literature there is still a lack of information about the machining processes of Nd-Fe-B magnets and the phenomena involved in the formation of the machined surface, such as the diamond wire cutting process. Thus, the objective of this study was to evaluate the surface integrity and magnetic properties resulting from diamond wire cutting of Nd-Fe-B based magnets. Cutting experiments of Nd-Fe-B magnets were carried out. The cutting speed (vc) was of 10 m/s, feed rate (vf) of 1 mm/min and final thickness of the samples of 500 µm. The results obtained showed that the hardness of the machined surface with diamond wire sawing and electropolished were lower than the faces just polished, which can be attributed to the presence of residual stress. Despite the brittle nature of the material, it was observed the presence of microcutting over the machined surface when used diamond wire sawing. However, due to the brittleness of the Nd-Fe-B, the machined surface also presented pittitng and craters. Regarding to the surface roughness, it was observed that the increase of the outer diameter and the size of diamond grain of the cutting tool resulted in the increased the Ra, Rq and Rt values. This behavior is attributed to the higher penetration depth of the diamond grains on the surface of the workpiece, favoring the formation of craters. The phases analysis via X-RD revealed just presence of hard magnetic phase (Nd2Fe14B1 grain), with some peaks related to the oxides phases. For the magnetic property, it was possible to observe that the Hcj presented closed values when varying the diamond wire. Thus, the diamond wire sawing and electropolishing are potential processes to be applied to manufacturing of Nd-Fe-B micro-magnets.
Keywords
NdFeB, diamond wire, surface integrity, Magnetic Properties, Micromachining
