Micro ultrasonic machining and self-aligned multilayer machining/assembly technologies for 3D micromachines

Micro ultrasonic machining (micro-USM) is proposed for the fabrication of 3D microstructures with high aspect ratios. The combination of WEDG and EDM provides a capability of making co-axial microtools for USM and thereafter, microholes as small as 15 /spl mu/m in diameter and a variety of high-aspect-ratio microstructures have been achieved for the first time. Also in this paper a 3D complete micromachine manufacturing method-self-aligned multilayer machining and assembly is presented. Using this technology two kinds of 3D micro air turbines, center-pin bearing air turbine and force-balance air turbine, have been successfully realized.