• The Magazine of the IEIE
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• v.28 no.3
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• pp.30-42
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• 2001

초소형의 전자 부품, 의료기기 및 광부품 등의 핵심부품들에 관한 산업계와 소비자의 욕구에 발맞추어 과학 기술의 진보가 요구되고 있다. 전통적인 금속 가공 방법과 MEMS와 같은 미세 부품 성형 방법의 중간적인 형태의 Milli-Structure 생산 기술은 근간의 추이에 발맞추어 차세대 국가경쟁력 강화를 위한 핵심기술로 주목받고 있다. 본 논문에서는 미세 부품 성형에 관련하여 국외 개발 동향을 검토하고 국내의 연구 상황을 본 연구팀의 연구를 위주로 하여 미세 소성 가공과 미세 기계 가공으로 분류하여 검토해 보기로 한다.

• Journal of the Korean Society for Precision Engineering
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• v.17 no.7
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• pp.14-19
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• 2000

현재 자본재산업의 기술낙후는 상품의 수출경쟁력 약화의 근원적인 원인이 되어 결국 지속적으로 선진국의 기술종속을 심화시키고 있다. 이러한 자본재 산업의 문제는 현재의 주력 수출상품의 핵심요소부품생산기술의 미비가 큰 원인이며(거의 주요핵심부품 도는 관련기술은 거의 대부분 수입에 의존하고 있음), 같은 논리로 차세대 신기술의 개발을 통한 첨단 상품의 개발도 이에 필요한 핵심요소부품의 생산기술이 뒤를 바쳐 주지 못한다면 결국 10년 후에도 현재와 같은 현상이 되풀이될 것은 분명하다.(중략)

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.4
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• pp.356-361
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• 2020

This paper presents a lightweight milli-scale crawling robot that can crawl on both sides, which was inspired by the movement of insects. This robot has an excellent ability to overcome obstacles, such as the narrow gaps and the rough terrain. In addition, the robot can crawl steadily and rapidly through triangular alternation, such as ants or cockroaches. The process of smart composite microstructures (SCM) was employed to make a lightweight robot structure. The SCM process replaced the conventional mechanical parts with flexure joints and composite links, which allows the weight of the robot to be reduced. In addition, the robot structure was robust against external impacts owing to the compliance of the constituent materials. Using the SCM process, the robot weighed only 32g with twelve legs in total on both sides. The robot showed a crawling speed of 0.52m/s on the front side and 0.42m/s on the backside.

• Transactions of Materials Processing
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• v.13 no.3
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• pp.242-247
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• 2004

Literature review on reliability test method for developing high performance optical/thermofluidic components. Since the miniaturization by the conventional mechanical process is limited to milli-structure, i.e. $10^{-3}m$, new technology for fabricating of mechanical components is needed to match cost, reliability, and integrability criteria of micro-structure. Although numbers of various researches on MEMS/MOEMS devices and components, including material characterization, design and optimization, system validation, etc., the lack of standards and specifications make the researches and developments difficult. For that reason, this paper is intended to propose the methods of reliability test for measuring the mechanical property of optical/ thermofluidic components.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.06a
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• pp.1261-1264
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• 2005

Recently, as researches and developments for milli-structure and micro machine are actively progressing, manufacturing technologies and skills for tiny small machine parts are getting more important. So, we have been trying to cut using high revolution air bearing spindle and micro-endmill, and studying for magnitude of cutting force, cutting force wave form and surface roughness. We figured out that in 60,000rpm is so slow that cutting is not perfact. Chatter occured to $2\mu{m}/rev\;at\;80,000rpm\;and\;4.4\mu{m}/rev$ at 100,000rpm. We confirmed that spindle run out increased surface roughness at high revolution.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2001.05a
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• pp.221-224
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• 2001

The dynamic characteristics of a hydraulic press for micro-stamping are investigated by Finite Element Analysis. This machine requires high precision in producing milli-structure of electric products such as TFT-LCD back-up light reflector. First, the modal analysis of the parts and the assembly of the hydraulic press is performed. Then, the sensitivity analysis is carried out. The results show that the bearing stiffness and the base mounting stiffness affect the specific mode shapes.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2000.11a
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• pp.739-742
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• 2000

Micro machining technology has been studied to fabricate small size and high accuracy milli-structure products. To perfectly overcome the conventional mechanical machining methods, the chemical mechanical micro machining(C3M) process was developed. The mechanism of C3M process is that chemical solution etches the material and results in the generation of the chemical reacted layer, and the mechanical micro tool subsequently removes the layer. From the fundamental experiments, the C3M process has been founded to have the advantages of lower machining resistance, tool wear, and higher surface quality and form accuracy than conventional methods. This study focuses on the micro grooving of both the metallic material(SKDII, A1) and hard brittle silicon oxide.

• Journal of the Korean Society for Precision Engineering
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• v.20 no.9
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• pp.32-39
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• 2003

Pulse electrochemical machining process with high or low current density may produce a non-lustrous surface on workpiece surface. The usual polishing process to remove a black layer from the surface has been hand polish the part. But the milli-to-micro meter scale structure formed by the electrochemical machining process may be destroyed while polishing process. The application of ultra short voltage pulses based on the analysis of electrical double layer charging process allows high resolution electrochemical machining and polishing. This technique was based on the specific polarization resistance from the comparison of ideal and experimental potential variation during short voltage pulses.

• Explosives and Blasting
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• v.14 no.4
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• pp.4-12
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• 1996

In '50, It was turnning point of tunneling technology that v-cut of single Face replaced by Burn cut.. Which was a standard Blasting formula. In '70, We faced Seoul Sub-Way construction by NATM. As it was damages to the Structure on the surface, finally we made empirical formula. For Granite $V=kw^{0.57}D^{1.75}$ For Grneiss $V=KW^{0.5}D^{1.75}$ For Concrete breaker $V=KW^{0.5}D^{1.75}$ (K=7) The magnitude of groun vibration can be reduced as using follow matters. First, by using explosive that have low dencity and low Velocity of detonation. Second adopting two stage deck charging, third, by using Milli Second electric Caps and Multi-Sequency blasting machine.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2001.05a
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• pp.231-234
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• 2001

Shearing, including blanking, trimming, piercing, etc, is one of the most frequently used processes in sheet metal manufacturing. In this paper, an individual set of tooling with an in-die sensor was designed and precisely fabricated to carry out the experiment for the shearing process investigation. Through various experiments, it has been examined the influence of process parameters such as clearance, edge material properties and pad configuration. Since the tension between the part and the scrap increases when the clearance increases, the clearance should be selected properly in order to reduce the burr height. Also removal of the lower pad makes the sheared surface worse and the shearing system unstable. The shearing force increases when the clearance decreases and the friction of the tooling material decreases. Dynamic reaction force is also important to obtain the fine sheared surfaces.