Narito Shibaike

A conceptual design environment for micromechanisms

This paper presents the use of a knowledge based system and a knowledge sharing environment to support the design of micromechanisms. Based on the experience of a design project, we discuss knowledge representation concerning the function and behavior for supporting functional decomposition. For the knowledge sharing environment, we have extended a finite element analysis system to allow the designer to perform analysis over the network.

Micromachining and focused ion beam etching of Si for accelerometers

Silicon microfabricated devices are being developed for reliable low cost sensors including accelerometers with tunnel junction readout. Using bonded silicon on insulator wafers as the starting material, novel structures are made by conventional surface micromachining followed by focused ion beam etching through 7 micrometers thick Si cantilevers at oblique angles to form submicron gaps to be closed by electrostatic actuation.

Approach to higher reliability in 3D micromechanisms

A micro-reducer characterized in its small size, high resolution ration and high reliability has been developed to achieve sufficient performance after 5,000,000 high-speed rotations1. A 3K-type mechanical paradox planetary gear reduction system was chosen in mechanical design. The size of a reducing part is 3 x 3.8 x 1.3 mm, and its reduction ratio is about 200. The module of the fine gears is 0.03. Alloy tool steel and WC-Ni-Cr super hard alloy were selected for the materials. The mechanical, thermal and environmental attributes were investigated by the properties of the materials suitable for micro fabrication on the specific strength and resistance to thermal distortion as the functional performance, and energy content of the material as the environmental impact. Micro-EDM process was optimized to accurately shape such a microscopic components. Surface modification by DLC, CrN, and MoS+-2) thin film was applied by rotating deposition technique to improve the surface-based attributes such as hardness, friction coefficient and resistance to wear. Several kinds of lubrication and bearing systems were evaluated to understand their internal energy dissipation and durability. This report presents such a synthetic approach for the micro-reducer to be steady, efficient and durable.