Micromachining of magnetic materials

The results of an investigation of laser-cutting and EDM of NdFeB and MnZn ferrite are presented. Using a sub-microsecond-pulsed Nd:YAG laser (lambda = 1.06 mu m) at a repetition rate of 1 kHz and pulse energy of 1.8 mJ, the 0.5 mm thick ceramic NdFeB and ferrite plates were cut at a approximate speed of 1 mm/s in 6-8 passes. The cut width was in the range of 65 to 80 mu m in the case of NdFeB, and 30 to 50 mu m for ferrite. Cutting in water provided best cut quality and elimination of the debris compared to cutting in air. The cutting of the ferrite by pulsed laser beam was found to lead to cracking of the material and is not recommended. Wire EDM gave good results both for cutting of NdFeB and ferrite despite of relatively high resistivity of the latter. Average surface roughness of cuts was 0.5 mu m. (C) 1999 Elsevier Science S.A. All rights reserved.