• Journal of Institute of Convergence Technology
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• v.2 no.2
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• pp.25-29
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• 2012

Micro machining technologies have been required to satisfy various conditions in a high-technology industry. Micro electrochemical process is one of the most precision machining methods. Micro electrochemical process has been divided into electrochemical etching through protective layer and electrochemical machining using ultrashort voltage pulses. Micro shaft can be fabricated by electrochemical etching. The various protective layers such as photo-resist, oxide layer and oxidized recast layer have been used to protect metal surface during electrochemical etching. Micro patterning on metal surface can be machined by electrochemical etching through protective layer. Micro hole, groove and structures can be easily machined by electrochemical machining using ultrashort voltage pulses. Recently, the groove with subnanometer was machined using AFM.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1997.10a
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• pp.1080-1083
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• 1997

Micro-stereolithography is a newly proposed technology as a means that can fabricate 3D micro-structures of free form. It makes a 3D structure by dividing the shape into many slices of relevant thickness along honzontal surfaces, hardening each layer of slice with a laser, and stacking them up to a des~red shape. Scale effect becomes important in this micro-fabrication process, d~fferently from the conventional stereolithography. To realize this micro-stereolithography technology, we developed an equipment using Ar+ laser, xyz stages, controllers and all the optic devices. Using the equipment, a number of micro-structures were successfully fabricated including a winecup of several tens of micrometers.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2003.06a
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• pp.1907-1910
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• 2003

Miniaturized machine tool can be used to produce 3D features based on CNC and PC-NC technology in the micro/meso scale. Wide applications of CNC technology are developed and there are lots of know-hows in the cutting process and their CNC application. It helps micro/meso scale structure to machine components, which can be used directly for practical applications. In the present research, as the machine tool is miniaturized, the manufacturing machine tools costs less when compared to the equipment used in other micromachining technologies. Moreover, with advancement of micro tool technology, the cutting process can be used to produce micro/meso scale parts. In conclusion, the proposed system can reduce the cost by utilizing the current machining technology, and as a result, complex micro/meso parts can be produced efficiently with high productivity.

• 유체기계공업학회:학술대회논문집
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• 2004.12a
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• pp.754-760
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• 2004

The miniaturization and integration are trend of modern blood analyses. Micro-Bio-Fluidics plays an important role in a micro blood analysis system. In this paper, analysis and design technology for blood analysis system is presented. Numerical simulations of a blood flow in micro separator and reservoir are conducted. As a result, we suggest on-chip micro separator, which performed plasma separation from whole blood in micro channels.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2003.10a
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• pp.313-317
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• 2003

Micro-Channel ultra-precision polishing is a new technology used in magnetic field-assisted relishing. In this paper, an electromagnet or the i18 of test system was designed and manufactured. A size of magnetic abrasive is used on 25~75${\mu}{\textrm}{m}$ and for the polish a micro-channel upper part. A surface of channel which is not even is manufactured using magnetic abrasive finishing at upper surface of micro-channel. As a result, the surface roughness rose by 80％ after upper surface of micro- channel was polished up 8 minutes by polishing.

• Current Optics and Photonics
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• v.2 no.6
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• pp.540-546
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• 2018

We propose an implementation scheme for an optical encryption system with hybrid-pattern random keys. In the encryption process, a pair of random phase keys composed of a white-noise phase key and a structured phase key are positioned in the input plane and Fourier-spectrum plane respectively. The output image is recoverable by digital reconstruction, using the conjugate of the encryption key in the Fourier-spectrum plane. We discuss the system encryption performance when different combinations of phase-key pairs are used. To measure the effectiveness of the proposed method, we calculate the statistical indicators between original and encrypted images. The results are compared to those generated from a classical double random phase encoding. Computer simulations are presented to show the validity of the method.

• Transactions of the Korean Society of Machine Tool Engineers
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• v.16 no.6
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• pp.193-200
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• 2007

Micro forming is a suited technology to manufacture very small metallic parts(several $mm{\sim}{\mu}m$). Al5083 superplastic alloy with very small grains has a great advantage in achieving micro deformation under low stress due to its relatively low strength at a specific high temperature range. Micro forming of $Zr_{62}Cu_{17}Ni_{13}Al_8$ bulk Metallic glass(BMG) as a candidate material for this developing process are feasible at a relatively low stress in the supercooled liquid state without any crystallization during hot deformation. In this study, the micro formability of Al5083 superplastic alloy and bulk metallic glass, $Zr_{62}Cu_{17}Ni_{13}Al_8$, was investigated with the specially designed micro vibration forming system using pyramid-shape, V-shape and U-shape micro die pattern. With these dies, micro vibration forming was conducted by varying the applied load, time. Micro formability was estimated by comparing the hight of formed shape using non-contact surface profiler system. The vibration load effect to metal flow in the micro die and improve the micro formability of Al5083 superplastic alloy and $Zr_{62}Cu_{17}Ni_{13}Al_8$ bulk Metallic glass(BMG).

• International Journal of Aeronautical and Space Sciences
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• v.17 no.4
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• pp.614-621
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• 2016

Micro-Doppler (MD) shift caused by the micro-motion of a ballistic missile (BM) can be very useful to identify it. In this paper, the MD signatures of three scale-model BMs are investigated using a portable measurement system. The measurement system consists of an X-band 2-by-2 phase comparison mono-pulse radar, and a mechanical device that can impart controlled spinning and coning motions simultaneously to a model to yield the MD signature that replicates the characteristic of each target and the corresponding micro-motion. The coning motion determined the overall period of MD, and the spinning motion increased its amplitude. MD was also dependent on aspect angle. The designed system is portable, and can implement many micro-motions; it will contribute to analysis of MD in various situations.

• Journal of Institute of Convergence Technology
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• v.4 no.2
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• pp.41-45
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• 2014

Micro fabrication technologies of aluminium have been required to satisfy many demands in technology fields. Pulsed laser beam machining can be an alternative method to accomplish the micro machining of aluminium. Pulsed laser beam can be applied to micro machining such as micro drilling and milling. Using pulsed laser beam, the machining characteristics of aluminium in micro drilling and milling were investigated according to average power, repetition rate, moving speed of spot. The laser beam machining with the optimal conditions can achieve precise micro figures. As a result, micro pattern, text and structures on aluminium surface was successfully fabricated by pulsed laser beam machining.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.12 no.3
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• pp.28-35
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• 2013

Micro electrical discharge machining (EDM) as a non-contact machining process is very effective for micromachining with a thin electrode because of its low machining reaction force. The micro-electrode machining device has the advantage of maintaining high precision through the whole processes and uses a feeding wire in the thin electrode tool manufacturing process. This study describes the design and evaluation of a micro-electrode machining device using optical photo-interrupter. The electrode was fabricated by reverse electrical discharge machining. The performance of designed system was evaluated to measure tension force according to feed speed of wire. This system for micro electrode fabrication proves the feasibility in the micro-EDM process of the micro holes and parts for industrial applications.