• 제목/요약/키워드: Film Thickness

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마그네트론 스파터시 금속 극박막의 실시간 전기저항과 미세구조 변화 (In-Situ Electrical Resistance and Microstructure for Ultra-Thin Metal Film Coated by Magnetron Sputtering)

  • 권나현;김회봉;황빈;배동수;조영래
    • 한국재료학회지
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    • 제21권3호
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    • pp.174-179
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    • 2011
  • Ultra-thin aluminum (Al) and tin (Sn) films were grown by dc magnetron sputtering on a glass substrate. The electrical resistance R of films was measured in-situ method during the film growth. Also transmission electron microscopy (TEM) study was carried out to observe the microstructure of the films. In the ultra-thin film study, an exact determination of a coalescence thickness and a continuous film thickness is very important. Therefore, we tried to measure the minimum thickness for continuous film (dmin) by means of a graphical method using a number of different y-values as a function of film thickness. The raw date obtained in this study provides a graph of in-situ resistance of metal film as a function of film thickness. For the Al film, there occurs a maximum value in a graph of in-situ electrical resistance versus film thickness. Using the results in this study, we could define clearly the minimum thickness for continuous film where the position of minimum values in the graph when we put the value of Rd3 to y-axis and the film thickness to x-axis. The measured values for the minimum thickness for continuous film are 21 nm and 16 nm for sputtered Al and Sn films, respectively. The new method for defining the minimum thickness for continuous film in this study can be utilized in a basic data when we design an ultra-thin film for the metallization application in nano-scale devices.

커넥팅로드 베어링의 유막두께에 미치는 기관 운전조건 및 윤활유의 영향 (The Influence of Engine Operating Conditions and Lubricants on Oil Film Thickness of Engine Connecting Rod Bearing)

  • 이동호;장병주
    • 한국자동차공학회논문집
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    • 제2권5호
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    • pp.1-10
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    • 1994
  • By applying of total electric capacitance method on engine connecting rod bearing during engine operating, the influence of engine operating conditions and lubricants on bearing oil film thickness was investigated. Minimum oil film thickness increases with kinematic viscosity, but as increasing of viscosity, the increasing ratio of film thickness is reduced. Also minimum oil film thickness increases with engine speed but there is a limit. Above this limit, film thickness decreases in opposition because of crankshaft inertia. As increasing of engine torque and oil temperature, munimum oil film thickness decreases linearly. For non-Newtonian oils, the correlation between $100{\circ}C$ kinematic viscosity and munimum oil film thickness is very poor.

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Optimization of Process Parameters for Dry Film Thickness to Achieve Superior Water-based Coating in Automotive Industries

  • Prasad, Pranay Kant;Singh, Abhinav Kr;Singh, Sandeep;Prasad, Shailesh Kumar;Pati, Sudhanshu Shekher
    • Corrosion Science and Technology
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    • 제21권2호
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    • pp.121-129
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    • 2022
  • A study on water-based epoxy coated on mild steel using the electroplating method was conducted to optimize the process parameters for dry film thickness to achieve superior paint quality at optimal cost in an automotive plant. The regression model was used to adjust various parameters such as electrode voltage, bath temperature, processing time, non-volatile matter, and surface area to optimize the dry film thickness. The average dry film thickness computed using the model was in the range of 15 - 35 ㎛. The error in the computed dry film thickness with reference to the experimentally measured dry film thickness value was - 0.5809%, which was well within the acceptable limits of all paint shop standards. Our study showed that the dry film thickness on mild steel was more sensitive to electrode voltage and bath temperature than processing time. Further, the presence of non-volatile matter was found to have the maximum impact on dry film thickness.

로커암 밸브 트레인의 동적 탄성유체윤활 유막 연구 (Dynamic Elastohydrodynamic Film Thickness in Rocker-Arm Valve Train System)

  • 장시열;이희락
    • Tribology and Lubricants
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    • 제19권4호
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    • pp.195-202
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    • 2003
  • Many computational researches have been performed about EHL film thickness in the contact between cam and follower in the engine valve train system. However, those computations do not explain the characteristics of dynamic film thickness which means squeeze film effect. Without the consideration of transient term in the Reynold's equation, the predicted film thickness from steady state condition has large difference from the actual film thickness. In this study, we have investigated the kinematic and dynamic simulations of rocker-arm valve train system. From the dynamic simulation, the applied load and the entraining velocity of the lubricant between cam and follower are obtained and with these values the dynamic film thickness is computed by Newton-Raphson method and compared with the steady state film thickness.

로커암 밸브 트레인의 동적 탄성유체윤활 유막 연구 (Dynamic Elastohydrodynamic Film Thickness in Rocker-Arm Valve Train System)

  • 이희락;장시열
    • 한국윤활학회:학술대회논문집
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    • 한국윤활학회 2000년도 제32회 추계학술대회 정기총회
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    • pp.397-405
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    • 2000
  • Many computational researches have been performed about EHL film thickness in the contact between cam and follower. However, those computations do not explain the characteristics of dynamic film thickness which means squeeze film effect. Without the consideration of transient term in the Reynold's equation, the predicted film thickness has large difference from the actual film thickness. In this study, we have investigated the kinematic and dynamic simulations of rocker-arm valve train system. From the simulation, the applied load and the entraining velocity of the lubricant between cam and follower are obtained and with these values the dynamic film thickness is computed by Newton-Raphson method and compared with the steady state film thickness.

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Hamrock과 Dowson의 EHL 유막두께식에 대한 평가 (An Evaluation of the Hamrock and Dowson's EHL Film Thickness Formulas)

  • 박태조
    • Tribology and Lubricants
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    • 제12권3호
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    • pp.115-122
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    • 1996
  • In this paper, a finite difference method and the Newton-Raphson method are used to evaluate the Hamrock and Dowson's EHL film thickness formulas in elliptical contact problems. The minimum and central film thicknesses are compared with the Hamrock and Dowson's numerical results for various dimensionless parameters and with their film thickness formulas. The results of present analysis are more accurate and physically reasonable. The minimum film thickness formula is similar with the Hamrock and Dowson's results, however, the central film thickness formula shows large differences. Therefore, the Hamrock and Dowson's central film thickness formula should be replaced by following equation. $H_{c} = 4.88U^{0.68}G^{0.44}W^{0.096}(1-0.58e^{-0.60k})$ More accurate film thickness formula for general elliptical contact problems can be expected using present numerical methods and further research should be required.

열진공성형 공형조건이 적층필름의 두께분포에 미치는 영향 (Effects of Processing Conditions on Thickness Distribution for a Laminated Film during Vacuum-Assisted Thermoforming)

  • 유영길;이호상
    • 소성∙가공
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    • 제20권3호
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    • pp.250-256
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    • 2011
  • Vacuum-assisted thermoforming is one of the critical steps for the successful application of film insert molding(FIM) to parts of complex shapes. If the thickness distribution of the formed film is non-uniform, cracking, deformation, warping, and wrinkling can easily occur at the injection molding stage. In this study, the effects of processing parameters, which include the film heating time, plug depth, plug speed and vacuum delay time, on film thickness distribution were investigated. It was found that the film thickness at the part sidewall decreases with increasing the film heating time and plug depth, but the thickness at the bottom was found to exhibit the opposite behavior. The film thickness of the sidewall was observed to increase at higher plug speed and vacuum delay time of 0 ~ 0.3sec.

Oil Film Thickness Measurement of Engine Bearing and Cam/tappet Contact in an Automotive Engine

  • Choi, Jae-Kwon;Min, Byung-Soon;Han, Dong-Chul
    • Tribology and Lubricants
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    • 제11권5호
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    • pp.71-77
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    • 1995
  • The capacitance technique was used to measure the minimum oil film thickness in engine bearing and the central oil film thickness between cam and tappet. This method is based on the measurement of total capacitance of oil film. For the measurement of the oil film thickness between cam and tappet, two surfaces were assumed to be flat and parallel within the Hertzian region and all the measured capacitance originated from this region. Shear rates from the measured minimum oil film thickness are over 10$^{6}$ sec$^{-1}$ in the greater part in both two cases. The minimum oil film thickness in engine bearing is larger than the surface roughness. Between cam and tappet it is mostly smaller than the surface roughness. In spite of the awkward restriction of the reliability of measured oil film thickness, it was known that the capacitance technique makes it possible to measure the oil film thickness in elastohydrodynamic and mixed lubrication regimes as well as in hydrodynamic regime. Therefore, it is also possible to classify the lubrication regimes based on the oil film thickness.

A Study on the Circumferential Groove Effects on the Minimum Oil Film Thickness in Engine Bearings

  • Cho, Myung-Rae;Shin, Hung-Ju;Han, Dong-Chul
    • Journal of Mechanical Science and Technology
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    • 제14권7호
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    • pp.737-743
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    • 2000
  • This paper presents the effects of circumferential groove on the minimum oil film thickness in engine bearings. The fluid film pressures are calculated by using the infinitely short bearing theory for the convenience of analysis. Journal locus analysis is performed by using the mobility method. A comparison of minimum oil film thickness of grooved and ungrooved bearing is presented. It is found that circumferential $360^{\circ}$ groove only reduces the absolute magnitude of the oil film thickness, but $180^{\circ}$ half groove affects the shape of film thickness curve and position of minimum oil film thickness.

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탄성 유체 윤활에서의 유막 두께 측정에 관한 정성적 분석 (Qualitative Analysis of Film Thickness in Elastohydrodynamic Lubrication)

  • 최언진;박경근;장시열
    • Tribology and Lubricants
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    • 제16권5호
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    • pp.317-323
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    • 2000
  • The film thickness and shape of elastohydrodynamic lubrication is measured by optical interferometer, which is the most precise method for EHL film measurement. However, the interpretation of the image pattern from optical viscometer is not simple for two-dimensional shape. A newly developed method of image processing makes it possible to evaluate the film thickness and shape in every point of contact region with two dimensional aspects. In this study, we captured the film shape of EHL film by the monochromatic incident light and analyzed the film thickness with the image processing method, which uses phase shift method. From the values of intensity in fringes, the qualitative feature of film thickness in the contact area are obtained by using Zernike polynomial