工具磨耗에 따른 切削力의 動特性에 대한 硏究

吳錫炯,羅義均 군산대학교 1992 群山水産專門大學 硏究報告 Vol.26 No.1

In recent year, owing to the automization of cutting tools, in-process dectction is more and more important. It is necessary to find how to estimate the tool wear because of problem about precision. Most of studies on in-process detection of tool wear have been carried out by prediction of tool life and measurement of force, heat, vibration, AE(acoustic emission) and image processing in cutting. In this paper, we deal with the relations of tool wear by variations in dynamic cutting force and then derived to correlate the wear with the dynamic component cutting force in the machining SUS304 which is welknown as difficult -to-machine material. The results obtained are as follows 1. At the view point of machinability for tool wear, even in case of same uncutchip cross-sectional area, to makes the slenderness ratio higher is advantageous. 2. The characteristics of RMS in cutting forces is correlated the wear and characterized by the tool life. It is suggested that applying the RMS to in-line process is a effective methods for detecting the tool wear.

재설계된 무시동 열전모듈 냉방기를 이용한 상용트럭 캐빈 내의 열유동 수치해석

오석형,김장권 한국동력기계공학회 2023 동력시스템공학회지 Vol.27 No.5

In this study, the three-dimensional heat flow field within the cabin, formed by installing a redesigned non-starting thermoelectric module type air cooler at the rear upper part of a large truck cabin, was analyzed in an incompressible, steady state using a realizable k-ε turbulence model. The new air cooler adopted a new flow path with lower system resistance to secure more air flowrate than the existing air cooler. As a result, the operating points of the new air cooler analyzed by rotation speed showed that a large air flowrate was obtained at a relatively lower static pressure than the conventional air cooler, and the air flowrate range required for effective heat exchange was about 2.6 m3/min to 3.9 m3/min at a rotation speed of 1,000 rpm to 1,400 rpm. Therefore, the temperature reduction effect of the new air cooler in the cabin is significantly improved compared to the existing air cooler, and low noise is expected due to low rotation speed making it very suitable for night cooling.

열전모듈 냉방기의 속도변화에 따른 상용트럭 캐빈 내의 열유동 수치해석

오석형,김장권 한국동력기계공학회 2023 동력시스템공학회지 Vol.27 No.3

In this study, the three-dimensional heat flow field in the cabin formed by installing a thermoelectric module type air cooler at the rear upper part of the cabin for a commercial truck was analyzed in an incompressible and steady state with a realizable k-ε turbulence model. As a result, the operating points analyzed by the number of revolutions of the air cooler are obtained with a relatively high static pressure, the effect of reducing the temperature in the cabin is significantly reduced due to insufficient air flowrate, and an increase in operating noise is expected. In addition, it is necessary to replace the virtual cross-flow fan, which causes high static pressure and insufficient air flowrate, and a redesign to secure the flow path cross-sectional area of the heat exchanger to the level of the air cooler discharge cross-sectional area is required. 이번 연구는 상업용 트럭 캐빈 후면 상단부에 열전모듈형 냉방기를 설치하여 형성된 캐빈 내3차원 열유동장을 Realizable k-ε 난류모델로 비압축성, 정상상태에서 해석하였다 그 결과 냉방기의회전수별로 해석된 운전점들은 비교적 높은 정압으로 얻어져, 부족한 풍량으로 인해 캐빈 내 온도 감소 효과가 현저히 떨어지며, 운전 소음의 증대가 예상된다. 그리고 높은 정압과 부족한 풍량을 초래하는 가상 관류홴의 교체가 필요하며, 열교환기의 유로 단면적을 냉방기 토출 단면적 수준으로 확보하는 재설계가 필요하다.

알루미늄합금 절삭시 절삭성과 절삭조건의 상관성에 관한 연구

오석형,Oh, Seok-Hyung 한국기계가공학회 2004 한국기계가공학회지 Vol.3 No.4

Using NC or CNC machine tool, the unmanned automatic production system has been growing recently in the manufacturing field. Thus it is important to find out the machinability of cutting force, tool wear and surface roughness during the cutting process. It is necessary to find how to estimate the machinability for the effective cutting condition because of problem about cutting power, tool wear, cutting time and precision. This study was planned to discover the relations of tool wear by variations of roughness and derived to correlate the wear with the surface roughness on the cutting parameter(cutting force, flank wear, surface roughness, friction angle, shear angle, slenderness ratio) when the aluminum alloy was cut in turning.

난삭재 가공기술 및 연구동향

오석형 한국공작기계학회 2003 한국공작기계학회지 Vol.12 No.1

Titanium의 切削에서 Saw-toothed Chip의 切削 Energy에 관한 硏究

吳錫炯,徐南燮 全北大學校 1987 論文集 Vol.29 No.-

In metal cutting, various types of chips are produced. W. Rosenhain classified them into flow-type, shear-type, pluck-off-type and tear-type. In the experiment, Nakayama found the chips whose shapes were saw-toothed-like and which were produced periodically. Since then this type of chip has been called saw-toothed chip. When this chips occur, the cut surface is smooth and the required cutting force is small. Nakayama and Ueda insist that saw-toothed chip is formed by the brittle fracture, the vibration, and etc. They studied about the effect of cutting depth, true rake angle on the slip and pitch. But there has not been report on the cutting energy with saw-toothed chip. This report shows how the depth of cut, true rake angle, and cutting speed effect on the cutting energy in machining titanium. The results are as foolows: 1. The specific cutting force decreases with the increase of the pitch. 2. The normal stress and the shear stress on the shear plane decrease with the increase of cutting depth. They are almost independent on the variation of true rake angle. 3. The unit friction energy on the tool face and the unit shear energy on the shear plane decrease with the increase of true rake angle and cutting depth. 4. The saw-toothed chip is formed in the case that the depth of cut is deeper than 0.03mm, and the smaller the true rake angle is, the larger the range, where saw-toothed chip is formed, is.

工具磨耗에 따른 切削溫度의 變動 特性에 관한 硏究

吳錫炯 군산대학교 1993 群山水産專門大學 硏究報告 Vol.28 No.1

This study is planned with the variation of temperature that is closely associated with the wear when SUS304 is cut. Since SUS304 is a difficult-to-machine material, tool damage is largely affected by cutting conditions, this experiments investigate the relations between the cutting temperature and the characteristics of tool wear which is being in cutting process. In the results, the characteristics of cutting temperature are related to the difficulty of machining characteristics.

유압펌프 자동ㆍ고속 성능 시험기의 개발에 관한 연구 (Ⅱ) - 제어 시스템 -

오석형(S.H. OH),김정호(J.H. KIM),김신(S. KIM),정석훈(S.H. JUNG),정재연(J.Y. JUNG) 한국자동차공학회 1996 한국자동차공학회 춘 추계 학술대회 논문집 Vol.1996 No.6_2

Recently, the automotive industy is improved rapidly. On this, a demend of high quality performance-test-machine for oil hydraulic pump is increased too. In this part, The interface skill between sensor and personal computer, data acquisition & display system and integrated control technology are important control technologies.<br/> Therefore, in this study, we designed a preformance-test-machine using above key technologies and we also maked a integrated PC control system using personal computer which is more progressive and flexible method than PLC control.<br/>

굴절링크 붐을 갖는 장비의 끝점 좌표 추적 알고리즘 개발에 대한 연구

오석형(Seok-Hyung Oh),홍용(Yong Hong) 한국동력기계공학회 2016 동력시스템공학회지 Vol.20 No.3

WEB기반의 3차원 유동속도 원격 계측시스템 개발에 관한 연구

오석형(S. H. Oh),김장권(J. K. Kim),나의균(E. G. Na) 한국동력기계공학회 2009 한국동력기계공학회 학술대회 논문집 Vol.2009 No.6

This paper shows the development process for measuring three-dimensional flow velocity components in a web-browser. The system is developed in an embeddable C/C++ interpreter Ch and Ch-CGI toolkit. The interface for the web-based measurement system consists of a set of web html files and Ch files for CGI. All of data in web browser are passed to Ch-CGI script to generate the output of new html file. PC-Server and PC-Client can submit measurement parameters and receive the text/graphical results each other. PC-Client can control the test equipment by using a parameters that received from PC-Server. It also can pass the test results between the web-based measurement system. In summary, the designed measurement system is evaluated, the outputs shown well on the web browser.