Cylindrical Ultrasonic Linear Microactuator Using Electroformed Ni Pipe

A piezoelectric linear ultrasonic microactuator with a cylindrical stator structure using electroformed Ni pipe is proposed. The length and diameter of the microactuator are about 8.2 and 2.0 mm, respectively. The stator consists of two piezoelectric ceramic (PZT) tubes connected by a 25 μm thick electroformed Ni pipe. Traveling wave propagation is generated on the electroformed Ni pipe in finite element method (FEM) simulations. The traveling wave propagation is obtained in the FEM simulation under the proper geometrical sizes, suitable boundary conditions and driving voltage signals. The trajectories of particles on the electroformed Ni pipe are elliptical motion. In the experiment, the traveling wave propagation was observed by a laser Doppler vibrometer system at the driving frequency of 701 kHz. Bi-directional motion of the slider was observed at the frequency of around 701 kHz and applied voltage V1 of 10-40 Vp-p. At this condition, the maximum output force and maximum velocity were about 0.6 mN at V1 = 30 Vp-p and 27.3 mm/s at V1 = 40 Vp-p, respectively.