High strength rare earth-iron-boron printed magnets used in a long throw-high force electromagnetic actuator with microfabricated coils

Rare earth-iron-boron magnets were successfully integrated in a surface micromachined electromagnetic actuator. The magnets are 2000 by 1000 /spl mu/m with thickness varying from 100 to 200 /spl mu/m and were screen printed on electroplated cantilever beams fabricated above 40 turn planer coils on a silicon wafer. The magnetic paste used to form the magnets was made from 40 /spl mu/m diameter spherical powder with a polyimide binder. The residual induction (B/sub r/) was 3000 Gauss (0.3 T) and the intrinsic coercivity (H/sub ci/) was 8050 Oe (644 kA/ m). Displacements of more than 1000 /spl mu/m with 200 mA of current and repulsive and attractive forces on the order of 1 /spl mu/N/mA at were demonstrated. The magnets produced forces on the order of 3 mN when in contact with ferromagnetic metals (Fe) or similar magnets.