Three-Degree-of-Freedom Electromagnetic Microactuator With Powder-Based Sm-Fe-N Magnets and Parylene Beams

In this paper, we report a moving magnet type electromagnetic actuator with three-degree-of-freedom, namely the displacement in XY axes and rotation around Z axis, by utilizing rare earth magnetic powder Sm-Fe-N. Parylene was utilized to fabricate springs to suspend four drive units and a center moving stage located in the four corners and the center of the actuator, respectively. The rare earth magnetic powder Sm-Fe-N with wax were embedded in the silicon frames of the drive units with a parylene layer, followed by magnetization by an 8 T pulse magnetic field to obtain permanent micromagnets. The motion of the center moving stage can be controlled by the drive units. To obtain an in-plane displacement in the XY axes, compensation coils were fabricated in a print circuit board (PCB) to eliminate the Lorentz force in the Z axis. The application of a direct current (DC) allowed the center moving stage to move in the XY axes by 55 $\mu \text{m}$ and rotate almost 3 degrees around the Z axis, respectively. The resonance frequencies of the motion in the XY axes and the rotation around the Z axis were 630 Hz and 675 Hz, respectively.