• 대한기계학회논문집A
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• 제41권9호
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• pp.845-851
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• 2017

외경에 홈이 존재하는 자긴가공된 압력용기의 피로 파손은 외경 홈에서의 피로균열 발생과 전파에 의해 발생한다. 자긴가공된 압력용기의 피로수명을 예측하기 위하여 유한요소법을 이용하여 자긴가공에 의한 잔류응력해석을 수행하였으며, 피로시험을 통하여 재료의 피로특성을 구하였다. 압력용기의 수명은 압력용기 외경 홈 모서리에서 응력 및 변형률 집중에 의한 피로균열의 생성수명과 전파수명의 합으로 총 수명이 계산되었다. 본 연구에서 80 % 자긴도의 압력용기가 424 MPa의 반복적인 내압을 받을 때 압력용기의 수명은 2,598 사이클로 예측되었다.

• Current Research on Agriculture and Life Sciences
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• 제22권
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• pp.41-48
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• 2004

본 연구는 예취시 벼 줄기의 절단 저항이 적은 콤바인 예취날 개발에 필요한 기초 자료를 제공하기위하여 예취날의 윗날 내부에 면적 $75mm^2$의 평면 홈을 가공한 개발날과 시중에 판매되는 예취날을 사용하여 절단속도비와 볏짚의 함수율을 인자로 미예취시 예취날의 구동 마찰저항과 예취저항을 측정한 결과는 다음과 같다. 1. 예취날 속도 0.37m/s에서 0.55m/s범위 내에서 단날 구동시의 예취날 구동 마찰저항은 홈 가공을 한 개발 날이 평균 $0.12kg{\cdot}m$로 홈 가공을 하지 않은 기존 날의 평균 $0.16kg{\cdot}m$에 비해 25% 낮게 나타났다. 또한 양날 구동방식에서도 홈 가공을 한 개발말이 기존날에 비해 평균 26%정도 구동 마찰저항이 낮게 나타났다. 2. 절단속도비 10.에서 1.5범위 내에서 홈을 가공한 개발날의 볏짚 예취 저항은 기존 날에 비해 볏짚의 함수율 14.2%, 55.3%, 84.2%에 대해 각각 평균 12%, 15%, 20% 낮게 나타났다. 3. 예취날 구동 방식에 따른 볏짚 예취 저항은 양날구동방식이 $0.20kg{\cdot}m$로 단날 구동방식의 $0.24kg{\cdot}m$에 비해 평균 17%정도 낮게 나타났다. 4. 예취날의 최적 속도비는 볏짚의 함수율 변화에 따라 다르게 나타났으며 함수율 14.2%, 84.2%에 대해 각각 1.2, 1.4로 나타났다.

• 한국방송∙미디어공학회:학술대회논문집
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• 한국방송공학회 2013년도 하계학술대회
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• pp.385-386
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• 2013

최근 인터넷이나 스마트 홈 기기의 발달로 웹의 크기가 폭발적으로 증가함에 따라 인터넷상에 존재하는 웹 문서들을 추적하여 필요한 정보를 수집하는 기술이 중요성을 더해 가고 있다. 스마트 홈 클라우드 서비스는 스마트 홈과 클라우드가 융합된 기술로 개인과 가정에서 생성되고 소비되는 컴퓨팅 자원과 콘텐츠들을 외부 서버 또는 다른 가정과 필요할 때 결합하고 공유하는 서비스로, 더욱 만족스러운 서비스를 위해서는 사용자의 컨텍스트를 자동으로 수집, 처리, 가공해 주는 기능이 필요하다. 이에 본 논문에서는 사용자가 좀 더 편리하고 만족스럽게 가정내의 스마트 홈 기기를 사용할 수 있도록 사용자나 스마트 기기의 콘텍스트에 맞는 정보를 제공할 수 있는 클라우드 기반의 콘텍스트 크롤러를 연구 및 설계하였다

• 대한기계학회논문집A
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• 제26권7호
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• pp.1280-1287
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• 2002

The old technique of sandblasting which has been used for decoration of glass surface has recently been developed into a powder blasting technique for brittle materials such as glass, silicon and ceramics, capable of producing micro structures larger than $100{\mu}$ m. This paper describes the performance of powder blasting technique in micro-line grooving of glass and the effect of the number of nozzle scanning on the depth and width of line groove. Experimental results showed that increasing the no. of nozzle scanning resulted in the increase of depth and width in grooves. Increase of width which may cause several problems in the precision machining results from wear of mask film. Therefore, well-controlled masking process is the most important factor for micro machining of glass with accuracy.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1997년도 춘계학술대회 논문집
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• pp.987-992
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• 1997

Burrs always come out with the machining of ducterial with small size. Though the size of burrs is small, burrs dominate deterioration of the accuracy of the micro grooves. So the burr generation model especially side burr generation model was investigated to predict the size of the burrs at the given cutting conditions. The side shear plane is introduced to build the burr generation model and the width of side shear plane nomalized with cutting depth is defined with the shear angle. From the theoretical observation, the width of side shear plane can vary up 40% of the cutting depth. To determine the size of burr and stiffness, single groovings were carried out and it was found that there exist a critical depth of cut that the size or stiffness of the burr vary.

• 한국정밀공학회지
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• 제25권11호
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• pp.45-51
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• 2008

Successive micro-scale V-grooves and a grid of pyramids were machined by elliptical vibration tufting (EVC) to investigate feasibility of using EVC as an alternative method of creating micro-molds to photo-lithography and electroforming, which have been commonly employed. An elliptical vibration grooving machine was developed which consists of two orthogonally-arranged piezoelectric actuators, a diamond cutting tool, and a motorized xyz stage. The micro-scale features were machined on materials of copper, duralumin, nickel, and hastelloy and it was found that EVC significantly reduces cutting resistance and prohibits generation of side burrs and rollover burrs, thus resulting in improving machining qualify of micro-molds in ail experimented workpiece materials.

• 한국정밀공학회지
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• 제18권10호
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• pp.178-183
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• 2001

Abrasive jet machining(AJM) process is similar to the sand blasting and effectively removes hard and brittle materials. AJM has applied to rough working such as debarring and rough finishing. As the need for machining of ceramics, semiconductor, electronic devices and LCD are increasing, micro AJM is developed, and has become the inevitable technique to micromachining. This paper describes the performance of the micro AJM in micro grooving of glass. Diameter of hole and width of line in grooving is 80${\mu}{\textrm}{m}$. Experimental results showed good performance in micro grooving of glass, but the size of machined groove increased about 2~4${\mu}{\textrm}{m}$. With the fine tuning of masking process and compensation of film wear. this micro AJM could be effectively applied to the micro machining of semiconductor, electronic devices and LCD.

• 한국기계가공학회지
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• 제10권6호
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• pp.27-32
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• 2011

In recently, it is demanded development of manufacturing techniques for machining of various mechanical parts. Therefore the development of turning is one of the important manufacturing techniques. In this study, an experimental shape in tapered groove turning was suggested, and the turning process was investigated by analyzing cutting speed, feed rate, tapered angle, depth of cut. The surface roughness and cutting force change in the workpiece was measured. From the results, the optimum machining conditions are obtained by design of experiments.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2002년도 추계학술대회 논문집
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• pp.172-175
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• 2002

High speed machining is one of the most effective technologies to improve productivity. It can give great advantage for manufacture of die and Moulds. However, when machining of micro groove in high speed machining a severely thermal damage was generated on workpiece and cutting tool. Generally, the cutting fluid is used to improve penetration. lubrication. and cooling effect. In order to rise the performance of lubrication. it contains extreme pressure agents (Cl, S, P). But the environment of work room go bad by those additive. Therefore, the compressed chilly air with oil mist system was developed to replace the conventional cutting fluid system. This paper carried out the tests to evaluate the machinability by the cutting environment in high speed micro groove machining of NAK80 (HrC40). Compressed chilly air with oil mist was ejected on the contact area between cutting edge and workpiece. The effect of this developed compressed chilly air with oil mist system was evaluated in terms of tool life. The results showed that the tool lift of carbide tool coated TiAlN with compressed chilly air mist cooling was much longer than that of the dry and flood coolant when cutting the material.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2003년도 춘계학술대회 논문집
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• pp.1844-1847
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• 2003

Electrochemical micro-machining(EMM) is used to achieve a desired workpiece surface by dissolving the metal workpiece with an electrochemical reaction. This machining method can be applied to metal that is difficult to machining using other methods. The workpiece dissolves when it is positioned close to the tool electrode in electrolyte and current is applied. This aim of this work is to develop electrochemical micro-machining(EMM) technique for micro groove shape by establishing appropriate electrochemical parameters of machining