• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 2003년도 춘계학술대회 논문집
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• pp.167-172
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• 2003

The machining method by using end-milling tool has been applying in machining structures of various shapes because of the availability. Recently, all kinds of industries based on the parts of micro shape are developing, and the demands of mechanical micro machining technology are Increasing suddenly to produce these parts. According to such changes, the technology of the micro end-milling machining is applying as one of the most important machining means. This research is to aim at developing machining technology for various micro structures using micro end-mill. This paper introduces micro mechanical machining system with ultra precision, and demonstrates methods manufacturing all sorts of parts and moldings for industry and examples of applicable machining by using micro end-milling tool of micro sizes from hundreds to tens in diameter.

• 소성∙가공
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• 제15권9호
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• pp.673-678
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• 2006

Demands for micro parts have increased with recent advances in IT and machinery industries. However, the present technology loaves much to be desired to effectively produce parts with the volume of $1mm^{3}$ and less by mechanical method in large quantities. This paper provides a method for efficient quantity production of complete micro 3D structure using micro end-milling cutting process. The possibility has proven via manufacturing experiment of a multistage micro complex gear structure of $500{\mu}m$ in length, $500{\mu}m$ in maximum external diameter and a volume of $1mm^{3}$ and less.

• 한국기계가공학회지
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• 제8권1호
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• pp.31-36
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• 2009

Micro-machining technology has been adopted for shape accuracy of micrometer and sub-micrometer scale, surface roughness of tens nanometer in industries. In micro-machining process the quality of machined surface is derived from machining condition and tooling. This paper investigates AE(acoustic emission) and cutting force signals according to machined surface quality related to machining condition. Machined surface quality was analyzed by the AE and cutting force parameter which reflect surface morphology. The characteristics of signal were extracted for process optimization by monitoring both the tool condition and the machined surface texture in micro end milling process.

• 한국공작기계학회논문집
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• 제16권5호
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• pp.198-204
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• 2007

This study was carried out to develope a flow control system using to supply PR(photo-resist) in the semi-conductor manufacturing process. The features of this system are to be able to measure the high viscosity and micro-flow. To meet above study object some ideas was induced to design a new concept valve with new material, multi-cross wheel, and new sealing method etc.. As the evaluations on the developed micro-flowmeter it was enough satisfied to use at the IT industries such as photo-resist process.

• 한국기계가공학회지
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• 제19권5호
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• pp.38-44
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• 2020

Surface texturing of micro-dimples has been used in many manufacturing industries to reduce friction between two sliding contacted surfaces. Surface texturing decreases the frictional force owing to minimizing of the sliding contact area. In this paper, micro-dimples have been fabricated on an Al6061-T6 surface using a two-frequency elliptical vibration texturing (TFEVT) method. A high-frequency of 18 kHz and low-frequency of 250 Hz were applied to an elliptically-vibrated tool holder. The Stribeck curve was plotted to analyze the friction coefficient trends. Furthermore, the representative wetting index, such as the water contact angle (WCA), was measured by considering the friction coefficient. WCA is associated with micro-dimple density and associated parameters. Consequently, the dimpled surfaces with a low friction coefficient exhibited a relatively high WCA in the feed direction. According to the Stribeck curve, the dimpled surfaces demonstrate superior friction performance for mixed-film lubrication compared to the non-textured surface.

• 벤처창업연구
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• 제12권6호
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• pp.13-24
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• 2017

본 연구는 도시형소공인의 매출채권관리가 재무적 경영성과에 미치는 영향을 검정하고자 진행하였다. 도시형소공인을 대상으로 설문조사를 실시하여 분석하였으며 연구결과는 다음과 같다. 첫째, 도시형소공인을 대상으로 한 매출채권관리 요인(신용판매관리와 신용통제관리, 회수관리)은 재무적 경영성과에 정(+)의 유의한 영향을 미치며, 사전적 매출채권관리가 사후적 매출채권관리보다 재무적 경영성과에 유의하게 영향을 미치는 것으로 나타났다. 사전적 매출채권관리 중 신용판매관리는 재무적 경영성과에 유의한 영향을 미치지 않았으며 신용통 제관리의 구성요소인 관리조직과 규정, 계약체결관리, 대손통제가 재무적 경영성과인 안정성에 모두 정(+)의 유의한 영향을 미치는 것으로 나타났고, 수익성에서도 관리조직과 규정이 부분적으로 정(+)의 유의한 영향을 미치는 것으로 나타났으며, 사후적 매출채권관리인 회수관리는 재무적 경영성과에 유의한 영향을 미치지 않는 것으로 나타났다. 둘째, 재무적 경영성과 중 안정성은 조직만족에 정(+)의 유의한 영향을 미치는 것으로 나타났고, 반면에 수익성은 조직만족에 유의한 영향을 미치지 않는 것으로 나타났다. 본 연구의 시사점은 도시형소공인의 매출채권관리에 있어 사전적 매출채권 관리가 사후적인 매출채권관리보다 중요하다고 판단할 수 있다는 것이다. 사전적 매출채권관리는 계약체결 전인 신용조사, 분석 및 평가, 판매결정 등의 과정을 통해 계약체결과 동시에 채무이행을 원활하기 위하여 인적보증이나 물적담보 등을 설정하여 관리하는 절차를 의미하며, 반면에 채무불이행을 전제로 하는 사후적 매출채권관리는 이미 디폴트가 되어버린 매출채권에 대한 채권회수 및 대손상각으로 처리 시까지의 채권관리 절차로서 매출채권이 회수가 지연되거나 대손이 증가하면 기업의 유동성이 악화되고 더 나아가 기업은 파산위험(흑자도산)에 처할 수도 있다. 그러므로 본 연구는 도시형소공인이 상거래 계약체결 시 이행기일 내에 매출 채권 결제와 불량채권의 회수 가능성을 사전에 파악하여 양질의 계약형태 변화를 유도하도록 방향성을 제시하였다는데 의의가 있다.

• 한국기계가공학회지
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• 제11권1호
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• pp.62-67
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• 2012

Recently UV laser is widely used to process micro parts using various materials such as polymers, metals and ceramics because it has a very high intensity at the focused spot area. It is generally known that there are still some difficulties for alumina($Al_2O_3$) ceramics to directly make micro patterns like holes and lines on the surface of working material using 355nm UV laser because the alumina has a very low absorption coefficient at that wavelength. But nowadays new alumna with nano-porous holes is developed and applied to advanced micro functional parts of IT, BT and BT industries. In this paper, we are going to show the mechanism of photo-thermal ablation for nano-porous ceramics. Inside hole there is a lot of multiple reflections along the depth of hole. Experimentally we can find the micro hole drilling and micro grooving on the surface of nano-porous alumina.

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 2001년도 춘계학술대회 논문집(한국공작기계학회)
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• pp.275-280
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• 2001

Recently, the trends of industrial products grow more miniaturization, variety and mass production. Micro drilling which take high precision in cutting work is requested more micro hole and high speed working. Especially, Micro deep hole drilling is becoming more important in a wide spectrum of precision production industries, ranging from the production of automotive fuel injection nozzle, watch and camera parts, medical needles, and thick multi-layered Printed Circuit Boards(PCB) that are demanded for very high density electric circuitry. This paper shows the tool monitoring results of micro drill with tool dynamometer. And additionally, microscope with built-in monitor inspection show the relationship between burr in workpiece and chip form of micro drill machining.

• 한국기계가공학회지
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• 제8권4호
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• pp.20-27
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• 2009

The characteristics of titanium alloy as a relatively advanced material is low density, avirulent and, superior corrosive resistant, therefore the use of titanium alloy is increasing lately in aerospace and mechanical technologies, precision machinery, electronics industry, petro-chemical industries and biomedical areas. In these days, the titanium alloy product is required various surface qualities of not only smooth surface but also rough surface depending on usages. The purpose of this experimental research is to find the optimum surface roughness of titanium alloy of Ti-6Al-4V, by micro abrasive blasting as depending variable conditions of working pressure, nozzle size, working time, stand of distance and power particle size.

• 한국기계가공학회지
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• 제18권1호
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• pp.101-108
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• 2019

In this study, the hole-cavity resonance technology and the micro pore stainless chip sintering technology were fused to develop silencers with excellent noise attenuation performance even at fluid pressures exceeding 30 bar for the first time at home and abroad. As a result of this study, the noise attenuation performance was greatly improved as reflection, loss, and resonance were made to occur thousands of times simultaneously when fluids pass through the sintered micro pore stainless steel chip sound absorber. The noise of the gas emitted from the bomb without the silencer was shown to be 125dB. And noise test conducted after installation of the silencer showed the noise of 67dB. Given the study results, the amount of noise was greatly reduced in the sintered silencer.