슬롯형상의 연삭숫돌에 의한 평면연삭가공

왕덕현,김원일,강신엽,우정윤 한국공작기계학회 1999 한국생산제조학회지 Vol.8 No.1

An experimental study on the grinding temperature, surface roughness and Acoustic Emission(AE) signals was conducted with different shapes of wheel. The grinding characteristics for slotted shapes of wheel changed by width and helical angle, were compared with those by general one. Lower grinding temperature was obtained for 30˚ helical angle with 10㎜ width and Root Mean Square(RMS) values of AE signals were lower for slotted shapes rather than general one. Surface roughness characteristics of slotted shapes found to be rough, but the value of roughness for 45˚ helical angel with 6㎜ width, represented to similar tendency general one.

티타늄합금의 와이어 방전가공시 방전가공 조건의 영향

김종업,왕덕현,이윤경,김원일 한국공작기계학회 2001 한국공작기계학회 춘계학술대회논문집 Vol.2001 No.-

Titanium alloy conducted in this experimental study has superior corrosive resistant and is mainly used in aerospace, automotive and petro-chemical industries. It is also treated with important materials of domestic goods due to improvement of the standard of living. In this study specimens were processed in the wire EDM after annealing, solution treatment and aging. Results were obtained through repeated experments of main rough process and finish process with the change of process parameters. Processing characteristics such as surface hardness, surfaces roughness, shape of processed surface and components were measured. The results confirmed that the above mentioned elements were improved in accordance with the number of process. Therefore, the optimal wire EDM condition in accord with processing characteristics is proposed in this experiment.

티타늄합금의 열처리조건에 따른 와이어 방전가공 특성

김종업,왕덕현,김원일 경남대학교 신소재연구소 2001 신소재연구 Vol.13 No.-

실험에 이용된 티타늄합금은 내식성, 비강도가 우수하여 의료용품 및 생활용품으로 개발하는 소재이다. 본 연구에서는 압연재의 티타늄합금을 풀림 및 용체화·시효처리를 행하여 와이어 방전 가공 실험을 수행하였으며, 가공조건들을 변화시키면서 거친가공과 다듬질가공을 반복 실험하여 가공상의 특성값들을 측정 및 분석하여 가공현상을 파악하고 최적의 가공조건을 제시하고자 한다. Titanium alloys used in this experiment have a good corrosion resistance and specific strength, and are the materials newly developed for medical supplies and living goods. In this study the rolled titanium alloys are treated by annealing, solution and aging, and then machined by wire EDM according to the process conditions. The characteristics of surface hardness, surface roughness, shape of surface, and the surface structure are measured through all the experiment by repeating from main cut to finish cuts. It is confirmed to get better measured values as increasing the number of processing of wire EDM. In this experiment the major phenomena of the wire EDM process are studied for obtaining appropriate process conditions.

열처리된 티타늄 합금의 연삭가공 특성

허순,김원일,왕덕현,이윤경 한국공작기계학회 2000 한국공작기계학회 추계학술대회논문집 Vol.2000 No.-

A use of Titanium alloy as a structural material is increasing lately. Among those titanium alloys, Ti-6A1-4V alloy is the most popular one with taking 2/3 of it's market. Also, Ti-6AI-4V alloy can get the stability of organization and product measure, and the evaluation of the cutting ability and the mechanical characteristics. The point in titanium alloy work is on how treat the heat generated during grinding. Because the heat conductivity of titanium alloy is unnegligibly low, the grinding heat is accumulated in workpiece, and it cause the increasing of grinding grits' wear and the rough grinding surface. So, these characteristics in grinding of titanium alloy will change the mechanical characteristics of the titanium alloy. From this study, the mechanical characteristics of annealed Ti-6A1-4V alloy after grinding was concerned with checking out the bending strength values, and the factor of the change and the difference was analyzed after analyzing the surface roughness and the image from SEM.

절삭방향에 따른 볼엔드밀 가공면 형상 특성

박재율,왕덕현,김원일,김종업 경남대학교 신소재연구소 1999 論文集 Vol.11 No.-

초경 볼엔드밀로 일반 구조용강(SS41)을 자유곡면 형태로 가공하는 경우 가공방식 및 공구의 접촉각도에 따른 가공한 면의 표면특성을 연구하였다. 본 실험적 연구에서 이송간격(pick feed)이 1.2mm인 경우 경로간격방향의 표면거칠기값은 접촉각 70°에서 가장 양호한 값을 나타내고 있으며, 이송간격이 1.6mm인 경우에는 접촉각이 75°부근에서 가장 좋은 표면거칠기 상태를 나타내었다. 공구이송방향에서의 표면거칠기는 상향절삭이 하향절삭보다 훨씬 좋게 나타나며, 또한 하방향절삭이 상방향절삭보다 대부분 양호한 표면거칠기 상태를 나타내고 있었다. This study intends to find the most suitable surface roughness by finishing cut for many method of cutting direction. according to change of angles to contact workpiece and ball endmill for structural steel(SS41). The surface roughness of path interval direction is most suitable roughness when the contact angle is 70" for 1.2mm pick feed and the contact angle is 75°for 1.6mm pick feed. The surface roughness of tool path direction is better for up-cutting than down-cutting and represents a good result in average for downward cutting than upward cutting.

신경회로망을 이용한 ARS 장애음성의 식별에 관한 연구

조철우,김광인,김대현,권순복,김기련,김용주,전계록,왕수건 한국음성과학회 2001 음성과학 Vol.8 No.2

Speech material, which is collected from AR (Automatic Response System), was analyzed and classified into disease and non-disease state. The material include 11 different kinds of diseases. Along with AR speech, DA` (igital Audio Tape) speech is collected in parallel to give the bench mark. To analyze speech material, analysis tools, which is developed local laboratory, are used to provide an improved and robust performance to the obtained parameters. To classify speech into disease and non-disease class, multi-layered neural network was used. Three different combinations of 3, G, 1 parameters are tested to obtain the proper network size and to find the best performance. From the experiment, the classification rate of 92.5% was obtained.

로타리 연삭에 대직경 Si-wafer의 ELID 경면 연삭특성

박창수,김원일,이윤경,왕덕현,김경년 한국공작기계학회 2002 한국공작기계학회 춘계학술대회논문집 Vol.2002 No.-

Mirror surface finish of Si-wafers has been achieved by rotary in-feed machining with cup-type wheels in ELID grinding. But the diameter of the work piece is limited with the diameter of grinding wheel in the in-feed machining method. In this study, grinding experiments by the rotary surface grinding machine with straight type wheels were conducted, by which the possible grinding area of the work piece is independent of the diameter of the wheels. For the purpose of investigating the grinding characteristics of large scale diametrical silicon wafer, grinding conditions such as rotation speed of grinding wheels and revolution of work pieces are varied, and grinding machine used in this experiment is rotary type surface grinding m/c equipment with an ELID unit. The surface ground using the SD8000 wheels showed that mirror like surface roughness can be attained near 2~6 nm in Ra.

밀링가공에서 부등각 엔드밀의 절삭특성에 관한 고찰

이상복,김원일,왕덕현,김실경 한국공작기계학회 2003 한국공작기계학회 춘계학술대회논문집 Vol.2003 No.-

The experimental research was conducted to find an end mill with an ideal helix angle, which has a superior anti-vibration effect and a low machining-tolerance. A conventional endmill which all four blades are 30˚ helix angles and a different helix angle endmill which the opposite two blades are 30˚ and the other opposites are different helix angles were studied. The cutting force, machining tolerance and surface roughness were obtained. The AE signals appeared to have low values in up-milling rather than in down-milling. These are also appeared to have low values at low spindle revolutions rates. The cutting force values of Fxy and Fxyz were found to be increased according to the value of helix angle. In up-milling, it was difficult to find a definite tendency in machining tolerance, but in down-milling, machining tolerance of the different helix angle end mill was found to be lower than that of the convention end mill. There is a definite tendency that the surface roughness gets better as the RPM increases. In down-milling, Type A( 25˚+ 30˚) appeared to bring the most satisfactory result.

볼엔드밀 가공시 절삭깊이와 가공위치의 변화에 따른 표면정밀도

박성은,왕덕현,김원일,이윤경 한국공작기계학회 2000 한국공작기계학회 추계학술대회논문집 Vol.2000 No.-

Ball end milling process is widely used in the die and mould manufacturing because of suitableness for the machining of free form surface. But, as ball end mill is long and thin, it is easily deflected by cutting force. In this study, Cutting force, tool deflection and surface precision was measured according to the change of depth and cutting location. Cutting force was acquired with tool dynamometer and a couple of eddy-current sensor measured tool deflection in x-y direction each. After machining, surface precision was measured with roundness tester and coordination measuring machine for sculptured surface angle change and cutting depth.

적극성시 금속수지 복합재료의 방전가공 특성

이윤경,왕덕현,김원일,우정윤 경남대학교 신소재연구소 1996 論文集 Vol.7 No.-

알루미늄 기지에 30% 탄화규소(SiC)가 보강된 금속수지 복합재료에 대한 방전가공 실험을 가공조건들의 변화에 따라 진행하였다. 드릴가공시 높은 탄화규소의 보강 때문에 밑면에서 취성파괴가 발생하였다. 특성 평가로 전류와 듀티팩터의 변화에 따른 공막물제거 속도를 측정하였으면, 표면형상을 표면거칠기와 전자현미경 사진으로 평가하였다. 전류가 증가될수록 공박물제거속도는 증가하는 경향을 나타내나, 듀티팩터의 변화에 따라 0.45까지는 증가하난 그 이상에서는 휴지시간의 상대적인 감소로 칩방출 시간이 충분하지 못하여 큰 면화가 없었다. 최대 표면 거칠기는 전류 및 듀티팩터의 변화에 따라 다소 증가하는 경향을 나타내었으며, 방전가공은 전자 현미경 사진들로 관찰하여 보면 용융 후 재융착 과정이 있는 것으로 나타났다. Electrical Discharge Machining (EDM) of Metal Matrix Composite(MMC) material with 30% Sic particulate based on A1 matrix was conducted for various conditions. When drilling process was executed for small holes, brittle fracture was found near the bottom surface due to the higher Sic percentage. Material Removal Rate(MRR) was examined for different conditions and the surface morphology was evaluated by surface roughness parameters and Scanning Electron Microscopy (SEM) photographs. The higher the current is, the more MRR was obtained but the MRR was increased up to 0.45 of duty factor and decreased after that. The maximum surface roughness of EDMed surface was slightly changed with increased pulse current and increased with duty factor. The SEM photographs of EDMed surface showed recast region after melting.