Experimental Research on EDM-milling of Sintered NdFeB

Sintered NdFeB is widely used due to its excellent magnetic properties, but it is not suitable for machining by conventional machining methods due to its very high brittleness and hardness. Electrical discharge machining (EDM) is deemed to be an important method for machining sintered NdFeB without considering the hardness of the material. To address the problems of poor performance and high cost of EDM machining of sintered NdFeB, in this study, the effect of the EDM-milling process on the surface morphology, cross-section, material removal rate (MRR), surface roughness (SR), and electrode wear rate (EWR) of sintered NdFeB was investigated by varying parameters including current, pulse duration, and pulse interval. Comparative experiments with EDM have shown that the EDM-milling process has better performance on machined surfaces, with large craters of radial size and lower value of SR. Its cross-section has thinner recast layer and smaller range of heat-affected zone. The MRR is enhanced by a maximum of 162%. Moreover, the EWR for EDM and EDM-milling are close to zero.