• Title/Summary/Keyword: Mechanical parts

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NC tool path generation of arbitrarily shaped pockets

  • Suh, Yong-Seok;Lee, Kunwoo
    • 제어로봇시스템학회:학술대회논문집
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    • 1988.10b
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    • pp.901-908
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    • 1988
  • In machining die cavities or mechanical parts, we often encounter the needs to remove a material within a given boundary. Even though this pocket cutting capability has been implemented in many NC packages, most of them can handle convex shaped pockets bounded by curves of limited types and numbers. In this work, a procedure has been developed to machine pockets of a free surface bounded by lines, circular arcs and free curves. Also, the cutter location data is computed directly without using iterative method for better computational efficiency.

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Phase Changes of the STS 431 Martensitic Stainless Steel after High Temperature Gas Nitriding Treatment (STS 431 마르텐사이트계 스테인리스강의 고온 가스 질화 열처리에 따른 상변화)

  • Yoo, D.K.;Kong, J.H.;Lee, H.W.;Kang, C.Y.;Kim, Y.H.;Sung, J.H.
    • Journal of the Korean Society for Heat Treatment
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    • v.21 no.5
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    • pp.244-250
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    • 2008
  • This study has investigated the surface phase change, hardness variation, surface precipitates, nitrogen content and corrosion resistance in STS 431 (17Cr-2Ni-0.2C-0.01Nb) martensitic stainless steel after high temperature gas nitriding (HTGN) treatment at the temperature range between $1050^{\circ}C$ and $1150^{\circ}C$. The HTGN-treated surface layer appeared $Cr_2N$ of rod type, carbo-nitride of round type and fine precipitates in the austenite matrix. On the other hand the interior region where the nitrogen was not permeated, exhibited martensite phase. The surface hardness showed 250~590 HV, depending on the HTGN treatment conditions, while the interior martensitic phase represented 520 HV. The permeation depth of nitrogen increased with increasing the HTGN-treated temperature. The nitrogen concentration of the surface layer appeared approximately ~0.17% at $1100^{\circ}C$. On comparing the corrosion resistance between solution-annealed and HTGN-treated steels, the corrosion resistance of HTGN-treated steel was superior to that of solution-annealed specimens.

Tonality Design for Sound Quality Evaluation in Printer (프린터 음질평가를 위한 순음도 설계)

  • Kim, Eui-Youl;Lee, Young-Jun;Lee, Sang-Kwon
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.22 no.4
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    • pp.318-327
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    • 2012
  • The operating sound radiated from a laser printer includes tonal noise components caused by the rotating mechanical parts such as gear, shaft, motor, fan, etc. The negative effects of the tonal noise components need to be considered in the process of developing a sound quality index for the quantitative evaluation of the emotional satisfaction in terms of psycho-acoustics. However, in a previous paper, it was confirmed that the Aures tonality did not have enough correlation with the results of jury evaluation. The sound quality index based on loudness, articulation index, fluctuation strength has a little problem in considering the effects of rotating mechanical parts on the sound quality. In this paper, to solve the tonality evaluation problem, the calculation algorithm of Aures tonality was investigated in detail to find the cause of decreasing the correlation. The new tonality evaluation model was proposed by modifying and optimizing the masking effect, loudness ratio, and shape of weighting curve based on the basic algorithm of Aures tonality, and applied to two kinds of operating sound groups in order to verify the usefulness of proposed model. As a result, it is confirmed that the proposed tonality evaluation model has enough correlation and usefulness for expressing the tonalness in the operating sounds of laser printers. In the following paper, this results will be used to model the sound quality index as the input data by using the classification algorithm.

RESEARCH FOR ROBUSTNESS OF THE MIRIS OPTICAL COMPONENTS IN THE SHOCK ENVIRONMENT TEST (MIRIS 충격시험에서의 광학계 안정성 확보를 위한 연구)

  • Moon, B.K.;Kanai, Yoshikazu;Park, S.J.;Park, K.J.;Lee, D.H.;Jeong, W.S.;Park, Y.S.;Pyo, J.H.;Nam, U.W.;Lee, D.H.;Ree, S.W.;Matsumoto, Toshio;Han, W.
    • Publications of The Korean Astronomical Society
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    • v.27 no.3
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    • pp.39-47
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    • 2012
  • MIRIS, Multi-purpose Infra-Red Imaging System, is the main payload of STSAT-3 (Korea Science & Technology Satellite 3), which will be launched in the end of 2012 (the exact date to be determined) by a Russian Dnepr rocket. MIRIS consists of two camera systems, SOC (Space Observation Camera) and EOC (Earth Observation Camera). During a shock test for the flight model stability in the launching environment, some lenses of SOC EQM (Engineering Qualification Model) were broken. In order to resolve the lens failure, analyses for cause were performed with visual inspections for lenses and opto-mechanical parts. After modifications of SOC opto-mechanical parts, the shock test was performed again and passed. In this paper, we introduce the solution for lens safety and report the test results.

An application plan of NSWC-98/LE1 when predicting the reliability of mechanical components of design and development phase (체계 개발 단계별 기계 부품에 대한 신뢰도 예측 시 NSWC-98-LE1 적용 방안)

  • Kwon, Ki Sang;Park, Eun Sim;Cho, Cha Hyun;Lee, Dong Woo;Lee, Su Jung
    • Journal of the Korean Society of Systems Engineering
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    • v.4 no.1
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    • pp.35-43
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    • 2008
  • Generally, in analysis of reliability of Design and Development Phase, reliability of electrical components is analyzed based on standards such as MIL-HDBK-217F, Bellcore Issue 4,5,6 by analyzing stress of architectural side (Power, Voltage, Current and quality level of components) of weapon system and stress of operational side (operational environment, operational temperature, Operational Profile). But the reliability of mechanical components is analyzed based on the data book of failure history of mechanical parts called NPRD-95(Nonelectronic Parts Reliability Data-95) without any analysis of above stress. However, even if it's the same mechanical parts, it might have different failure rate(fatigue, wear, corrosion) during operation depending on how weary(stress : pressure, vibration, temperature during operation) the parts are. Therefore, analyzing reliability using just data book can cause big difference in reliability instead of analyzing based upon stressfulness that parts might have, operational concept, and other various factors. Thus, This paper will guide the way of predicting reliability by organizing ways of predicting reliability for system organization and adopt ing NSWC-98/LE1(Naval Surface Warfare Center-98/LE1) for mechanical components.

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Yoke Tube Crack Inspection by Using Acoustic Resonance Spectral Analysis (음향 공진 스펙트럼 분석을 통한 요크 튜브 크랙 검사)

  • Yeom, Woo-Jung;Hong, Yeon-Chan;Kim, Jin-Young;Kang, Joonhee
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.19 no.10
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    • pp.108-114
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    • 2018
  • Due to the development of nondestructive testing techniques, methods of inspecting cracks in mechanical parts have drawn attentions. Among various non-destructive testing methods the acoustic resonance method which analyzes the natural frequencies has been developed into a technique suitable for the prompt judgements of the existence of the defects in the mechanical parts. In this study, we investigated the crack inspection technique to examine the cracks in the yoke tubes by using the acoustic resonance method and realized the system to quickly detect the cracks. A 24bit ADC circuit and an MCU were installed for the smooth data collection, and a TCP / IP communication interface was configured for the data communication with PC. We used a microphone as a sensor measuring the vibrations. We constructed an analysis software to obtain the frequency spectra of the vibrations, to find the existence of the cracks, and to feedback to the user. Tests were conducted using the yoke tubes manufactured in the real industrial field. The tests were successfully conducted to distinguish the good products from the defective (cracked) products and confirmed that they can be employed in the actual industrial field.

Influence of Substrate Phase and Inclination Angle on Heat Transfer Characteristics in Vicinity of Hastelloy X Regions Deposited on S45C via Directed Energy Deposition (DED 공정을 이용한 S45C 위 Hastelloy X 분말 적층 시 기저부 상과 경사각이 적층부 인근 열전달 특성에 미치는 영향에 관한 연구)

  • Baek, Sun-Ho;Lee, Kwang-Kyu;Ahn, Dong-Kyu;Kim, Woo-Sung;Lee, Ho-Jin
    • Journal of the Korean Society of Manufacturing Process Engineers
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    • v.20 no.10
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    • pp.27-37
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    • 2021
  • The use of additive manufacturing processes for the repair and remanufacturing of mechanical parts has attracted considerable attention because of strict environmental regulations. Directed energy deposition (DED) is widely used to retrofit mechanical parts. In this study, finite element analyses (FEAs) were performed to investigate the influence of the substrate phase and inclination angle on the heat transfer characteristics in the vicinity of Hastelloy X regions deposited via DED. FE models that consider the bead size and hatch distance were designed. A volumetric heat source model with a Gaussian distribution in a plane was adopted as the heat flux model for DED. The substrate and the deposited powder were S45C structural steel and Hastelloy X, respectively. Temperature-dependent thermal properties were considered while performing the FEAs. The effects of the substrate phase and inclination angle on the temperature distributions and depth of the heat-affected zone (HAZ) in the vicinity of the deposited regions were examined. Furthermore, the influence of deposition paths on depths of the HAZ were investigated. The results of the analyses were used to determine the suitable phase and inclination angle of the substrate as well as the appropriate deposition path.

Micro Mold Machining Using EDM/ECM (방전/전해 가공을 이용한 미세금형가공)

  • Chung, D.K.;Shin, H.S.;Choi, S.H.;Kim, B.H.;Chu, C.N.
    • Proceedings of the Korean Society for Technology of Plasticity Conference
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    • 2007.05a
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    • pp.75-78
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    • 2007
  • Recently, the need for micro mold or micro mechanical parts has been rapidly increased. As feature size decreases, conventional machining processes show their limitation. Micro electrical discharging machining (EDM) and electrochemical machining (ECM) have many advantages in micro machining. They can be used to make structures of micro scale, or even nano scale size. In this paper, the application of micro EDM and ECM has been investigated.

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Development Status and Test Results of the 3 way Switch for the Urban Maglev (도시형 자기부상열차 3방향 분기기 개발현황 및 시험결과)

  • Lee, Jong-Min;Han, Hyung-Suk;Kim, Chang-Hyun;Shin, Hyeon-Jae;Suh, Sung-Ho
    • Proceedings of the KSR Conference
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    • 2011.05a
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    • pp.1742-1749
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    • 2011
  • The 3 way segmented Maglev switch is developed for the urban Maglev vehicle, which is scheduled to debut at the middle of 2013 in Incheon International Airport. The 3 way switch is composed of 3 moving girders, 4 fixed girders, driving units, moving units, clamping units and articulated angle relieving equipment etc. In this paper, the measured results on the interaction between vehicle and switch are discussed. The measured results are following; First, continuous moving test and natural frequency for girder and levitation rail. Second, levitation and lateral air gap of the bogies running on the curved switch. Third, noise of moving mechanical parts of the 3 way segmented switch. Forth, thermal displacement of the girder due to temperature change. With over the measured results, more reliability and stability of the 3 way segmented switch are secured.

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A Study on the Maintenance Period Optimization for the Urban Tansit Vehicles (도시철도차량 유지보수주기 최적화 연구)

  • Park, Kee-Jun;Chung, Jong-Duck;Suh, Myung-Won
    • Proceedings of the KSR Conference
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    • 2011.10a
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    • pp.22-26
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    • 2011
  • The urban transit vehicles has very complicated structures composed electric and mechanical parts and systems. Its system is important to insure operating stability pursuant to massive transfer. Also, its system takes a lot of maintenance cost than constructing cost due to its system which has longtime life cycle. Generally it is know that maintenance cost affect a lot on total cost because its life cycle cost takes a part more than 60~70%. For these reason, it is really important to reduce its maintenance cost through efficiently operation and maintenance management system construction.

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