Machinability of NdFeB magnet via wire and sinking EDM methods

Abstract

NdFeB magnet is widely used in many industries due to their powerful magnetic properties. However, it belongs to hard-to-machine material because of its mechanical characteristics. Electrical discharge machining (EDM) is an alternative competitive process to machine any material with high hardness and low flexural strength. Machinability and surface characteristics of EDMed NdFeB magnet surfaces are poorly understood. Wire EDM and sinking EDM with Cu-SiC electrode are explored the machining characteristics. Surface roughness, surface topography, surface alloying, and material removal efficiency have been characterized. Results show that EDM is an effective method to machine NdFeB magnet. The machined quality could be modified with the multiple cuts at reduced discharge energy in wire EDM. Six-sigma distribution of <i>R</i>_a in rough cut mode is different from that of trim cut modes. Electrode alloying to the work-piece can be negligible by using low discharge energy. The low toughness of NdFeB magnet would be the major contributing factor to the appearance of microcracks. The fabricated Cu-SiC electrode has better performance in terms of MRR and surface roughness.