Micro-machined Elements Research Articles

Recycling welding rod residuals based on development of a top-down nanomanufacturing system employing indexing equal channel angular pressing

Fusion welding processes such as shielded metal arc welding (SMAW) and gas tungsten arc welding (GTAW) are used extensively and economically in fabrication of critical engineering structures and components across varied industries and applications throughout the world. By-product inherent with these welding processes consists of varied discrete lengths of unused welding rod remaining at the end of the weld thermal cycle. These residuals are typically considered spent or scrap material with minimal engineering value. This paper, however, presents an experimental investigation to further process such materials into commodities and components of enhanced economic and engineering value. A novel prototype system identified as indexing equal channel angular pressing (IX-ECAP) was developed using modifications to traditional equal channel angular pressing (ECAP) to transform welding residuals into nanostructured or ultra-fine grained materials. Such materials with significantly enhanced performance characteristics can then be used as feed stock for potential uses as composite matrix reinforcements, micro-machine elements, and micro-fasteners. Micro-hardness conversions from processed material allowed theoretical determination of grain sizes employing Hall-Petch relationships. Analysis of variance (ANOVA) using a five-factor two-level fractional factorial split plot design (FFSP) studied significance of number of passes, pressing speed, temperature, back pressure, and vibration on material properties. IX-ECAP provided significant improvements in mechanical properties and offered a viable solution whereby processing of discrete variable length aluminum 4043 welding rod residuals proved very successful.

ファイバレーザによる 3 次元加工とマイクロシステムの構築

ファイバレーザによる 3 次元加工とマイクロシステムの構築

Scale Effect in Heat and Fluid Flow and Nano- and Micro-Machines

Micro- and nano-scale systems are explained and are categorized in terms of heat and fluid flow phenomena. Some typical applications of nano- and micro-machines are presented. Heat and fluid flow phenomena of nano-micro spatio-temporal systems are described as follows.Micro-systems:· The size of the micro-machine element ranges from 1 µm to 1 mm.· The fluid motion and heat transfer can be treated as a continuum, and is described by Navier-Stokes equations and Fourier's law.Nano-systems:· The fluid cannot be treated as a continuum.· Discontinuity and wave characteristics of fluid and energy have to be considered.

Material Selection for Photothermal Driving of Micromachine Elements

The photothermal effect, which changes light into heat, can be used to generate driving force from thermal stress. Micro-cantilevers, the simplest micromachine element, are driven using a modulated laser diode and the frequency response characteristics and deflection are measured. By applying photothermal driving to a micro-disk on a central pivot, a standing wave is generated. The optimum disk material parameters to maximize the driving force are investigated. The amplitude of the standing wave is found to increase as the thickness of the micro-disk is decreased and the amplitude increases with the ratio of the coefficient of thermal expansion and thermal conductivity. The amplitude also increases with laser output. It is found that stainless steel is the most suitable disk material.

I15 凹部を有する微小機械要素の精度計測のためのナノマシニング : 微小径先端を有する探針の試作(I1 加工・生産システム1(マイクロ技術の高度化))

I15 凹部を有する微小機械要素の精度計測のためのナノマシニング : 微小径先端を有する探針の試作(I1 加工・生産システム1(マイクロ技術の高度化))

Design considerations for negative Poisson ratio structures under large deflection forMEMS applications

Negative Poisson ratio (NPR) materials based on a re-entrant honeycomb structure expandin the direction perpendicular to an externally exerted tension. This feature makes NPRstructures attractive for use in microsensors and actuators as versatile motion transformers.When implemented in microdevices, where slender and flexible micromachined elements arewidely used, the NPR material can tolerate large deflections. In the present work,motivated by the development of an optical sensor based on a photonic crystaldevice attached to a NPR based structure, we analyze the behavior of re-entranthoneycomb structures under large deflections. The model of the structure is built usingextensible elastica theory for the description of geometrically nonlinear beams with anextensible axis. Results provided by the analytical model are compared with numericalresults obtained by the finite element method. It is shown that the Poisson ratio(ν), which is defined entirely by the initial geometry of the structureundergoing small deflections, becomes strain dependent at large deflections.The extensibility of the beam’s axis has a strong influence on theν of the structure at large deflections and leads to the appearance of a minimum on thestrain–ν curve. An example of design is demonstrated which yields a desired strain-independentν of the NPR structure under large deflections.

Application of platelet CVD diamond to micromachine elements

Applications of diamond to micro-scale machine elements often require the formation of sub-micron size patterns. Diamond may be an ideal candidate for obtaining structures of this scale due to its excellent mechanical properties and/or chemical stability and excellent tribological characteristics, and thus it may be a suitable material for such micromachine elements. Fortunately, platelet diamond prepared by the combustion flame method (Surf. Coatings Technol. 39/40 (1989) 235) is composed of hexagonal microplates and has a shape at the outset which makes it promising for use as a micromachine element material without requiring any elaborate machining operations. However, there have been no reports on the use of platelet diamond as a micromachine element material. In this paper, we report on experiments in which platelet diamond was applied to micromachine elements, such as a tool element for use as a micro-forming mold for plastics. A focused beam of 30 keV Ga+ ions was used in this work to fabricate sub-micron size patterns on the surfaces of single crystal diamond synthesized at a high temperature and high pressure, and on quasi-hexagonal platelet CVD diamond.

Optically driven micromachine elements

We report on a proof of principle demonstration of an optically driven micromachine element. Optical angular momentum is transferred from a circularly polarized laser beam to a birefringent particle confined in an optical tweezers trap. The optical torque causes the particle to spin at up to 350 Hz, and this torque is harnessed to drive an optically trapped microfabricated structure. We describe a photolithographic method for producing the microstructures and show how a light driven motor could be used in a micromachine system.

Detection of Defects in Micro-Machine Elements by Using Acoustic Waves Generated by Phase Velocity Scanning of Laser Interference Fringes

High aspect ratio microstructuring is a key process for fabricating microelectromechanical systems (MEMSs). Many microfabrication methods have been developed. Among them, inductively coupled plasma (ICP) source etching is especially attractive because it can fabricate high aspect ratio microstructures, at high speeds with a dry etching process. However, in such microstructures, it is difficult to nondestructively evaluate the quality of high aspect ratio etched bottoms. Therefore, we developed a technique for detecting defects in high aspect ratio microstructures on Si wafers machined by ICP source etching. Using acoustic waves generated by phase velocity scanning of laser interference fringes, we nondestructively detected 13-µm-high defects located on the bottom of narrow and deep grooves from the other side of the Si wafer, which could not be detected by means of optical techniques or a scanning electron microscope.

Displacement Analysis of Pantograph Mechanisms with Superelastic Hinges.

For handling of a micromachine element and / or its parts, use of a micromechanical system is suitable. Thus, a pantograph mechanism is made from a plastic resin and superelastic hinges simultaneously using a small injection molding machine. The shape memory alloy having an effect of superelasticity is used as superelastic hinges. Therefore it is possible for superelastic hinges to have large bending displacements. The input and output displacements of the pantograph mechanism with superelastic hinges are measured and their linear relationship is confirmed. Then a micromechanical system for microbonding by adhesives is constructed using piezoelectric actuators, the pantograph mechanism and a needle. We confirmed that the proposed mechanical system performs well for microbonding by adhesives.

Characteristic Analysis of Pantograph Mechanisms with Superelastic Hinges.

To handle a micromachine element and/or its parts, a micromechanical system is suitable. Thus, a pantograph mechanism is made from a plastic resin and superelastic hinges simultaneously by using a small injection molding machine. Superelastic hinges made of shape memory alloy have an effect of super-elasticity. Therefore it is possible for superelatsic hinges to have great bending displacements. The input and output displacements of the pantograph mechanism with superelastic hinges are measured and their linear relationship is confirmed. Then a micromechanical system for microbonding by adhesives is made from piezoelectric actuators, the pantograph mechanism and a needle. We confirmed that the proposed mechanical system performs well for microbonding by adhesives.

Digital flexure beam accelerometer

First Page

Development of a Machine Tool for Machining Fine Micro-hole on Glass and Ceramic Materials.

Applications of glass and ceramic materials to micro-machine elements in biotechnology and space engineering have led to a great demand for special machine tools which enable fine micro-machining on hard and brittle materials. The first part of this article describes a PZT actuator installed in a vibrating machine tool whose performance is tested on different materials. In the second part, we investigate the applicability of giant magnetostriction materials to a vibratory device for fine-micro machining tools.