• Journal of Powder Materials
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• v.20 no.5
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• pp.355-358
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• 2013

Micro trench structures are applied in gratings, security films, wave guides, and micro fluidics. These micro trench structures have commonly been fabricated by micro electro mechanical system (MEMS) process. However, if the micro trench structures are machined using a diamond tool on large area plate, the resulting process is the most effective manufacturing method for products with high quality surfaces and outstanding optical characteristics. A nonferrous metal has been used as a workpiece; recently, and hybrid materials, including polymer materials, have been applied to mold for display fields. Thus, the machining characteristics of polymer materials should be analyzed. In this study, machining characteristics were compared between nonferrous metals and polymer materials using single crystal diamond (SCD) tools; the use of such materials is increasing in machining applications. The experiment was conducted using a square type diamond tool and a shaper machine tool with cutting depths of 2, 4, 6 and 10 ${\mu}m$ and a cutting speed of 200 mm/s. The machined surfaces, chip, and cutting force were compared through the experiment.

• Smart Structures and Systems
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• v.12 no.6
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• pp.679-694
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• 2013

In this paper the application of the Interpolation Damage Detection Method to the numerical model of a suspension bridge instrumented with a network of Micro-Electro-Mechanical System sensors is presented. The method, which, in its present formulation, belongs to Level II damage identification method, can identify the presence and the location of damage from responses recorded on the structure before and after a seismic damaging event. The application of the method does not require knowledge of the modal properties of the structure nor a numerical model of it. Emphasis is placed herein on the influence of recorded signals noise on the reliability of the results given by the Interpolation Damage Detection Method. The response of a suspension bridge to seismic excitation is computed from a numerical model and artificially corrupted with random noise characteristic of two families of Micro-Electro-Mechanical System accelerometers. The reliability of the results is checked for different damage scenarios.

• Steel and Composite Structures
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• v.32 no.6
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• pp.753-767
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• 2019

Vibration control in mechanical equipments is an important problem where unwanted vibrations are vanish or at least diminished. In this paper, free vibration active control of the porous sandwich piezoelectric polymeric nanocomposite microbeam with microsensor and microactuater layers are investigated. The aim of this research is to reduce amplitude of vibration in micro beam based on linear quadratic regulator (LQR). Modified couple stress theory (MCST) according to sinusoidal shear deformation theory is presented. The porous sandwich microbeam is rested on elastic foundation. The core and face sheet are made of porous and three-phase carbon nanotubes/resin/fiber nanocomposite materials. The equations of motion are extracted by Hamilton's principle and then Navier's type solution are employed for solving them. The governing equations of motion are written in space state form and linear quadratic regulator (LQR) is used for active control approach. The various parameters are conducted to investigate on the frequency response function (FRF) of the sandwich microbeam for vibration active control. The results indicate that the higher length scale to the thickness, the face sheet thickness to total thickness and the considering microsensor and microactutor significantly affect LQR and uncontrolled FRF. Also, the porosity coefficient increasing, Skempton coefficient and Winkler spring constant shift the frequency response to higher frequencies. The obtained results can be useful for micro-electro-mechanical (MEMS) and nano-electro-mechanical (NEMS) systems.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.31 no.5
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• pp.550-555
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• 2007

The effective fracture toughness testing of materials intended for application in Micro Electro Mechanical Systems (MEMS) devices is required in order to improve understanding of how micro sized material used in device may be expected to perform upon the micro scale. ${\gamma}$-TiAl based materials are being considered for application in MEMS devices at elevated temperatures. Especially, in Alloy 4, both ${\alpha}_2$ and ${\gamma}$ lamellae were altered markedly in 3,000 h, $700^{\circ}C$ exposure. Parallel decomposition of coarse ${\alpha}_2$ into bunches of very fine (${\alpha}_2+{\gamma}$) lamellae. Parallel decomposition of coarse ${\alpha}_2$ into bunches of very fine (${\alpha}_2+{\gamma}$) lamellae. The materials were examined 2 types Alloy 4 on heat exposed specimen($700^{\circ}C$, 3,000 h) and no heat exposed one. Micro sized cantilever beams were prepared mechanical polishing on both side at $25{\sim}30{\mu}m$ and electro final stage polishing to observe lamellar orientation of same colony with EBSD (Electron Backscatter Diffraction Pattern). Through lamellar orientation as inter-lamellae or trans-lamellae, Cantilever beam was fabricated with Focused Ion Beam(FIB). The directional behavior of the lamellar structure was important property in single material, because of the effects of the different processing method and variations in properties according to lamellar orientation. In MEMS application, it is first necessary to have a reliable understanding of the manufacturing methods to be used to produce micro structure.

• 제어로봇시스템학회:학술대회논문집
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• 2001.10a
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• pp.103.1-103
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• 2001

This paper presents the development of a micro gripper for grasping miniature sized parts in micro-assembly. Particularly, we have paid attention to the problem of manipulating objects of a well defined size range: the one between 1 mm and 0.1mm. In fact, objects larger than 1 mm can be easily handled by conventional precise grippers, while objects smaller than 1 $\mu\textrm{m}$ can be manipulated with special tools like AFM or STM. In this range, we can distinguish between mechanical and biological objects. We have focused our gripping research on the micro mechanical objects. We started from a f degree of freedom planar configuration. The structure of the micro gripper was a type of the elastic flexure hinge and was fabricated in ...

• Proceedings of the KSME Conference
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• 2002.08a
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• pp.143-146
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• 2002

Recently the micro flows have been received much attention in the applications with regard to Micro Electro Mechanical Systems(MEMS). Such flows are governed by relatively large viscous forces, compared with inetia force, and frequently specified by slip wall boundary conditions. In the present study, computations are applied to investigate the compressible viscous flows through an extremely small channel, and theoretical analyses are conducted using the Fanno flow theory. The axisymmetic, compressible, Wavier-Stokes equations are numerically solved by a fully implicit finite implicit method. The predicted results are validated with previous experimental data available. The results obtained show that for small Reynolds numbers, the viscous frictional force significantly influences the compressible micro channel flows.

• Journal of the Semiconductor & Display Technology
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• v.3 no.2
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• pp.23-26
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• 2004

Thin film is one of the most general structures used in micro-electro-mechanical systems (MEMS). To measure the mechanical properties of SU-8 film, tensile testing was adopted which offers not only elastic modulus but also yield strength and plastic deformation by load-displacement curve. Tensile testing system was constructed with linear guided servo motor for actuation, load cell for force measurement and dual microscope for strain measurement.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.33 no.5
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• pp.106-114
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• 2005

• Ceramist
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• v.7 no.3
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• pp.21-27
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• 2004

MEMS(Micro Electro Mechanical Systems)는 초소형 구조물의 제작 기술인 마이크로머시닝 기술을 이용하여 제작되는 초소형 전자기계 시스템을 말한다. 최근 10여 년간 MEMS 기술이 상당히 진척되었고 다양한 마이크로머시닝 기술이 개발되었다. 이에 따라 이를 이용하여 다양한 MEMS 소자의 개발이 이루어지고 있다. 그 중에서도 MEMS 센서는 비교적 간단한 제작 공정과 작은 크기, 그리고 저비용으로 인하여 상품화가 쉽게 이루어지고 있다. (중략)

• Transactions of the Korean Society of Mechanical Engineers B
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• v.27 no.2
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• pp.236-242
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• 2003

Thermal bubbles find their diverse application areas in the MEMS (MicroElectroMechanial Systems) technology, including bubble jet printers, microactuators, micropumps, etc.. Especially, microactuators and micropumps, which use a microbubble growing by a controlled heat input, frequently involve mechanical and thermal interaction of the bubble with a solid structure, such as a cantilever beam and a membrane. Although the concept is experimentally verified that an internal pressure of the bubble can build up high enough to deflect a thin solid plate or a beam, the physics of the entire process have not yet been thoroughly explored. This work reports the experimental study of the growth of a thermal bubble while deflecting a thin cantilever beam. A physical model is presented to predict the elastic response of the cantilever beam based on the experimental measurements. The scaling law constructed through this work can provide a design guide for micro- and nano-systems that employ a thermal bubble for their actuation/pumping mechanism.