• 한국터널지하공간학회 논문집
• /
• 제4권4호
• /
• pp.287-300
• /
• 2002

터널굴착 발파기술로 새로 개발된 Composition Presplitting Angle Cut (COPA)은 기존 공법과는 달리 심발부에 먼저 인장파괴를 통하여 선균열 (사전절단)을 형성시킨다. 본 연구에서는 선균열 효과를 검증하기 위하여 굴진효율과 소음 진동의 발생크기를 측정하는 현장시험을 실시하였다. 그리고 이 공법의 경제성 및 작업성 (시공성)을 비교하기 위하여 동일한 조건에서 기존의 발파공법을 동시에 시험하여 그 결과를 비교하였다. 시험 결과 COPA - Cut 발파공법이 기존 발파공법보다 굴진효율이 증가하고 소음 진동이 감소되었다. 또한 경제성, 시공성 및 품질관리 측면에서 우수하다는 것을 확인 되었다.

• 한국정밀공학회:학술대회논문집
• /
• 한국정밀공학회 2003년도 춘계학술대회 논문집
• /
• pp.553-556
• /
• 2003

End-milling have been used in the industrial world because it is very effective to the manufacture of mechanical parts with various shape. Recently the end-milling processing is needed the high-precise technique with good surface roughness and rapid time in aircraft, automobile part and molding industry. Therefore this study carried to decide the optimum cutting condition for surface roughness and rapid manufacturing time using design of experiment and ANOVA. From the results of experimentation, surface roughness have an effect on cutting direction, spindle speed and depth of cut. And then the optimum condition used Taguchi design is upward cutting in cutting direction, 600rpm in spindle speed, 240mm/min feed rate, 2mm in axial depth of cut and 0.25mm radial depth of cut. By using design of experiment, it is effectively represented shape characteristics of working surface in end-milling.

• 한국신재생에너지학회:학술대회논문집
• /
• 한국신재생에너지학회 2008년도 추계학술대회 논문집
• /
• pp.10-13
• /
• 2008

Fuel cell systems have witnessed remarkable development in recent years as they offer a clean and efficient alternative for power generation. Testing was conducted to determine the safety performance of a residential fuel cell system when subjected to abnormal operation condition, especially for voltage sag and fuel cut. In case of voltage sag to 198V, its arriving time at rated power had shown a slight lag but there wasn't any noticeable change when operating it between rated voltage(220V) and 10% voltage sag(198V). In case of fuel cut, it also showed stable shut-down characteristics. The test results are being used to develop a new safety evaluation for residential fuel cell system.

• Corrosion Science and Technology
• /
• 제9권1호
• /
• pp.34-38
• /
• 2010

Electrochemical study on cut edge corrosion of prepainted Zn coated (GI) and 55%Al-Zn coated (GL) steels has been performed in wet-dry cyclic conditions. Maximum width of delaminated polymer coating from the cut edge for GI and GL specimens was evaluated under wet-dry cyclic conditions. The cyclic tests were carried out for 1000 h by changing of relative humidity, where the salt of NaCl was deposited on the specimen every 48 h. The cut edge corrosion test under NaCl deposit indicated that the delamination of the GL specimen progresses at a higher rate than the GI. The electrochemical corrosion monitoring was also performed under condition of alternate exposure to immersion in NaCl solution and drying at 60%RH and $25^{\circ}C$. On the basis of the results of the delamination tests and electrochemical measurements, the mechanism of cut edge corrosion for GI and GL were discussed.

• 한국기계가공학회지
• /
• 제7권4호
• /
• pp.142-148
• /
• 2008

This study aims to find the optimal cutting conditions, which are obtained by grinding condition, and the grinding characteristics and condition of constant velocity joint were investigated with respect to wheel velocity, depth of cut, feed speed. Grinding machine has been widely used in manufacturing optical reflects of metal. Such as steel are easy to be machined because of their proper material. As a result I obtained the data of grinding conditions makes good surface roughness and the optimal condition of grinding and get the mesh condition. The purpose of this study is to find the optimum grinding wheel characteristics for cutting constant velocity joint.

• 한국정밀공학회:학술대회논문집
• /
• 한국정밀공학회 1996년도 춘계학술대회 논문집
• /
• pp.34-38
• /
• 1996

Cylindrical plunge grinding is widely used for final machining process of precision parts such as automobile, aircraft, measurement units. In order to make parts which have high precison accuracy and high surface integrity, it is neccessary to consider grinding characteristics. these grinding characteristics are closely related grinding force. Soin this study, to examine closely characteristics of grinding force, effects of dressing condition, depth of cut and speed ratio on grinding force are considered. As the result, It is shown that grinding forces are affected bydressing condition, depth of cut and speed ratio and that there exist threshod grinding force and it also affected by dressing conditon.

• 대한안전경영과학회지
• /
• 제6권1호
• /
• pp.283-300
• /
• 2004

This paper describes the NC simulator system for Wire-cut electrodischarge machining. Electrodischarge Wire-cut machining is applicable to all materials including metals, alloys, and most carbides. Although CAM system generate the NC code considering electrodischarge conditions, incorrect Wire-cut tool path bring about fatal results. The simplest way of simulating a EDM process is to display the trajectory of Wire-cutter location by line segments. With this kind of simulation, the programmer can get a general idea about whether the wire is moving as planned but cannot locate gouging or excess material because only the wire location will be seen, not the changes in the workpiece as it is machined. The ideal way of simulating the EDM process is to display the solid model of the workpiece as it is machined. Therefore we propose the ideal NC simulator system for Wire-cut EDM.

• 한국기계가공학회지
• /
• 제2권3호
• /
• pp.20-25
• /
• 2003

The End-milling has been widely used in the industrial world because it is effective to cutting working with various shape. Recently the end-milling is demanded the high-precise technique with good surface roughness and rapid manufacturing time for precision machine and electronic elements. The cutting working of end-milling such as, cutting direction, revolution of spindle, feed rate and depth of cut have an effect on optimum surface roughness. This study was carried out to decide the working condition for optimum surface roughness and rapid manufacturing time by design of experiment and ANOVA. From the results of this study, the optimum working condition for end milling is upward cutting in cutting direction, 600rpm in revolution of spindle, 240mm/mm in feed rate, 2mm in axial depth of cut and 0 25mm in radial depth of cut. The design of experiment has become an useful method to select optimum working condition mend-milling.

• 한국지반공학회:학술대회논문집
• /
• 한국지반공학회 2005년도 춘계 학술발표회 논문집
• /
• pp.107-112
• /
• 2005

Road is built continuously along with development of industry and cut slope is happened necessarily in road construction. Geoengineers are executing cut slope stability analysis considering various cut slope condition such as topography, geology, hydraulic condition and so on. The Tertiary Jungja Basin is located in the southeastern coastal area of the Korea Peninsula. Jungja Basin area is created by geotectonic movement of the plate after Early Miocene epoch. The northwestern and southwestern boundary of the basin is fault zone. The Basement rock is hornfels (Ulsan Formation). Basin-fills consist of extrusive volcanic rock(Tangsa Andesites), unconsolidated fluviatile conglomerate(Kangdong Formation) and shallow brackish-water sandstone(Sinhyun Formation). The characteristics of cut slopes in this area is different with cut slopes in the other site. Soil layers in this area is unconsolidated sediments and is not formed the weathering and erosion of the rock. So, the depth of soil layer is very thick. Faults of this area are northwest-southeast and northeast-southwest direction. Expandible clay mineral as smectite, chlorite et al. detected from fault gouge using XRD. Therefore, Jungja Basin area must consider the characteristics of the faults and soil layers thickness necessarily cut slopes stability analysis.

• 한국안전학회지
• /
• 제12권4호
• /
• pp.9-14
• /
• 1997

From the experimental study of wire-cut Electric Discharge Machining for alloyed steel and tungsten carbide, the characteristics such as hand drum form has been observed and evaluated for various conditions. Hand drum form can be improved when gap voltage and spark cycle become smaller, their thickness become thinner, wire tension become larger and number of cutting is done so many times. When wire-cut 60mm thickness tungsten carbide in normal condition, Hand drum form becomes larger due to the low conductivity inducing cobalt composite rising by electrolysis.