• 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.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2006년도 춘계학술대회 논문집
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• pp.493-494
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• 2006

SU-8 can be implemented as a mask for micro Abrasive Jet Machining (micro-AJM) process [1]. In this paper, we will evaluate the quality of micro grooving result on glass substrate by micro-AJM process which using SU-8 as a mask. It was evaluated on width and edge profile of the micro grooving. The result was having distortion compare with the master film used to pattern the SU-8 mask. The value of distortion with other properties which came along with it, such as depth and surface roughness, can be optimized in order to fabricate micro-channel for micro-fluidic application.

• 한국정밀공학회지
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• 제13권1호
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• pp.123-130
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• 1996

The procedure on the design of a new tungsten cabide throw-away cutting tool system for deep grooving or cut-off machining is suggested. For relieving the maximum stress level at the corner radius of the blade holder, the finite element method is used. Also the pulling test device is proposed for measuring the holding force of the insert between the blade holder and the insert considering the materials in contact and configuration parameters of the holder.

• 식물병연구
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• 제29권2호
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• pp.193-199
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• 2023

The apple stem grooving virus (ASGV) is one of the most harmful latent viruses infecting pear orchards worldwide. To examine the genetic diversity of ASGV in Korean pear orchards, the complete coat protein (CP) gene of five ASGV isolates collected from various regions were identified. The five Korean ASGV isolates showed 88-96% nucleotide identity with the 11 isolates worldwide occurring elsewhere in the world. Phylogenetic analysis of five isolates, as well as the previously sequenced isolates, indicated that the ASGV clusters had no correlation with the host or geographical regions of origin. Recombination analysis showed that one of the five Korean isolates is a recombinant, with a recombination site in the CP gene region (nt 532-708). This study is the first report of natural recombination within the CP gene of ASGV isolates from pears grown in Korea.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2009년도 추계학술대회 논문집
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• pp.675-676
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• 2009

• 월간 기계설비
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• 통권103호
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• pp.65-72
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• 1999

• 한국산학기술학회논문지
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• 제10권1호
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• pp.19-24
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• 2009

구조물 동특성 변경법이란 부가 구조물의 첨가나 삭제, 재료 물성치의 변경, 구조물의 형상변경 등을 이용해 구조물의 동특성을 향상시킬 수 있는 매우 효과적인 방법이다. 하지만 이러한 구조물 동특성 변경법 중 구조물의 형상 변경을 통해 그 구조물의 동특성을 향상시키는 방법은 지금까지는 주로 엔지니어의 경험이나 많은 시간을 요하는 시행착오법에 의존해 왔다. 따라서, 앞선 연구를 통해 이러한 구조물의 형상 변경을 통한 동특성변경법에 있어서 기존의 경험이나 시행착오법에 의존하는 방법이 아닌, 체계화된 방법론을 제안하게 되었으며 하드디스크 드라이브 (HDD)에 성공적으로 적용하였다. 제안된 그루브를 통한 표면형상변형 동특성변경법을 검증해 보기 위하여, 본 연구에서는 모든 요소가 엠보싱 되어 있는 극한의 경우로부터 최적화를 수행하고 앞선 연구에서 얻어진 최적화 결과와 비교함으로써 제안된 방법론의 효과를 검토해 볼 수 있었으며, 1차 고유진동수를 높이기 위한 최적화 결과 그루브의 형상은 앞선 연구결과와 같음을 알 수 있었다.

• 한국신뢰성학회지:신뢰성응용연구
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• 제15권3호
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• pp.197-206
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• 2015

Failure analysis of pre-insulated pipe (SPPS 380, 400A) transporting high temperature water ($95{\sim}110^{\circ}C$) for a plant was carried out. The damaged area (${\Phi}5mm$) of pre-insulated pipe was found only on welds. The chemical composition of damaged pipe meets specification of carbon steel pipes for pressure service (KS D 3562). As results of microstructure analysis, crack propagated from outer to inside after pitting corrosion occurred on the outside surface. The non-metallic inclusion existed on the end of crack. And the non-metallic inclusion continuously and linearly formed along with the bond line of welds. Based on SEM-EDS analysis, the nonmetallic inclusions have higher Manganese (Mn) and Oxygen (O) content but sulfur (S) was not detected. As results of water quality analysis, hydrogen ion concentration and minerals like Fe, Mg, Si were in low level. But the content of dissolved oxygen (11.2 ppm) was slightly higher than that of standard. It seems that the cause of damaged pipe is grooving corrosion due to MnO inclusion formed on bond line and corrosion took place nearby welds.

• 한국생산제조학회지
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• 제22권3호
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• pp.408-413
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• 2013

Micro-features such as grooves and lenses, which perform optical functions in flat displays, should be manufactured with a good form accuracy because this is directly related to their optical performance. As the size of the display increases, it is very difficult to maintain a high relative accuracy because of the inherent geometric errors such as the waviness of a large-area plate. In this paper, the optical effect of these geometric errors is investigated, and surface-referenced micro-grooving to measure and compensate for such geometric errors on line is proposed to improve the form accuracy of the micro-grooves. A PZT-based fast depth adjustment servo system is implemented in the tool holder to maintain a uniform groove depth in reference to the wavy surface. Through experiments, the proposed method is shown to be an efficient way to produce high-quality micro- grooves on a wavy die surface.

• 한국정밀공학회지
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• 제23권1호
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• pp.64-71
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• 2006

Ultraprecision machining and MEMS technology have been taken more and more important position in machining of microparts. Micro endmilling is one of the prominent technology that has wide spectrum of application field ranging from macro parts to micro products. Also, the method of micro-grooving using micro endmill is used widely owing to many merit, but has problems of precision and quality of products due to tool wear and tool fracture. This investigation deals with state monitoring using acoustic emission(AE) signal in the micro-grooving. Characteristic evaluation of AE raw signal, AE hit and frequency analysis for condition monitoring is presented. Also, the feature extraction of AE signal directly related to machining process is executed. Then, the distinctive micro endmill state according to the each tool condition is classified by the fuzzy C-means algorithm.