Microfabrication of Sm2Co17 micromagnets for MEMS and micromotors using ultrashort pulsed hydro laser micromilling process

Abstract

Micromagnets have wide applications in MEMS and micromotors but there are some limitations in current microfabrication processes for permanent magnets. A novel damage-free ultrashort pulsed laser machining process to manufacture complex shapes of Sm2Co17 micromagnets is proposed in this work. This process permits to cut the microparts submerged in a refrigerant fluid. This is especially beneficial for magnets, which are very sensitive to high temperature, as the heat effect of laser cutting on the hard magnetic materials is drastically reduced. The detailed description of the manufacturing process is here presented. Results of several machining processes like milling and cutting and the magnetic characterization of the resulting micromagnets are shown. Complex segment shapes, with 65 µm thickness are achieved, made in high quality Sm2Co17 material. It is demonstrated that no permanent degradation of the magnetic properties appears after laser machining.