• Title/Summary/Keyword: Film Thickness

Search Result 3,877, Processing Time 0.031 seconds

Prediction of the Film Thickness Variation through Film Insert Thermoforming (필름 인서트 열성형 시 필름 두께분포 예측)

  • Kim, G.Y.;Lee, K.O.;Kang, S.S.
    • Proceedings of the Korean Society for Technology of Plasticity Conference
    • /
    • 2008.05a
    • /
    • pp.281-284
    • /
    • 2008
  • Film insert melding is one of the surface processes that enhances functional or aesthetic qualities of an existing product's surface. In general, film insert molding consists of three processes including thermoforming, trimming and injection molding. Thermoforming, which is the first process of film insert molding, is the most important process because the variation of film thickness has an effect on the mold design and process conditions for the subsequent processes, that are, trimming and injection molding. This study is focused on predicting the film thickness distribution through film insert thermoforming process using commercial FEM code. In order to describe rheological behavior of thermoplastic film (ABS), G'Sell's viscoelastic constitutive law was adopted. The numerical model of film insert thermoforming was established, and the simulation to predict film thickness distribution was performed. Comparison between the results of simulation and experiment was made to validate the proposed finite element analysis.

  • PDF

Fast Analysis of Film Thickness in Spectroscopic Reflectometry using Direct Phase Extraction

  • Kim, Kwangrak;Kwon, Soonyang;Pahk, Heui Jae
    • Current Optics and Photonics
    • /
    • v.1 no.1
    • /
    • pp.29-33
    • /
    • 2017
  • A method for analysis of thin film thickness in spectroscopic reflectometry is proposed. In spectroscopic reflectometry, there has been a trade-off between accuracy and computation speed using the conventional analysis algorithms. The trade-off originated from the nonlinearity of spectral reflectance with respect to film thickness. In this paper, the spectral phase is extracted from spectral reflectance, and the thickness of the film can be calculated by linear equations. By using the proposed method, film thickness can be measured very fast with high accuracy. The simulation result shows that the film thickness can be acquired with high accuracy. In the simulation, analysis error is lower than 0.01% in the thickness range from 100 nm to 4 um. The experiments also show good accuracy. Maximum error is under $40{\AA}$ in the thickness range $3,000-20,000{\AA}$. The experiments present that the proposed method is very fast. It takes only 2.6 s for volumetric thickness analysis of 640*480 pixels. The study suggests that the method can be a useful tool for the volumetric thickness measurement in display and semiconductor industries.

Measurement of two dimensional oil film thickness in piston by induced fluorescence method (유기형광법을 이용한 피스톤 유막두께의 이차원적 측정)

  • 민병순;최재권
    • Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
    • /
    • 1998.10a
    • /
    • pp.166-174
    • /
    • 1998
  • The distribution of oil film thickness in piston were measured by induced fluorescence method. A Xe lamp was used as light source. Coumarine-6 was mixed with oil as the fluorescent dye. Fluorescent signal which is proportional to the oil film thickness was acquired by CCD camera and transmitted to the personal computer as video signal. In order to solve the problem of measurement system, irregular distribution and unstability of light intensity, as well as to know the relationship between the oil film thickness and output signal, three different calibration techniques were used. Motoring and firing tests were performed in a single cylinder research engine with transparent liner. By analyzing the oil film thickness converted from the photographed image, it was observed that each of three piston rings scrapes the oil both upward and downward and oil film thickness is not uniform horizontally at a given piston land. The amount of oil in each land was considerably affected by the engine load. It is thought that the blow-by gas blows the oil down to the crankcase.

  • PDF

Optimization of Specific Film Thickness for a Disc Cam Using Genetic Algorithm (유전자 알고리즘을 이용한 원판 캠의 비 유막두께 최적화)

  • Kwon, Soon-Man;Kim, Chang-Hyun;Nam, Hyoung-Chul;Shin, Joong-Ho
    • Transactions of the Korean Society of Mechanical Engineers A
    • /
    • v.32 no.11
    • /
    • pp.924-929
    • /
    • 2008
  • The rate of wear of cam followers in a valve train system is mainly a function of contact stress between the cam and the follower, sliding velocity and hydrodynamic film thickness between the two mating surfaces. The wear or surface fatigue can be reduced by maximizing the elastohydrodynamic film thickness. In this paper, an attempt has been made to estimate the optimal specific film thickness of cam-follower system quantitatively. A general TES polynomial function with real values of exponents is developed and genetic algorithm (GA) is used as optimization techniques for maximizing the minimum specific film thickness. The optimization programs enumerate values of the exponents for synthesis of cam displacement curves. The results show that the minimum film thickness can be increased considerably, e.g. approximately 7% in this paper.

The Effect of Oil Rheology on Film Thickness in Engine Journal Bearing (윤활유의 유동특성이 기관 저어널 베어링의 유막두께에 미치는 영향)

  • 이동호;장병주
    • Transactions of the Korean Society of Automotive Engineers
    • /
    • v.2 no.4
    • /
    • pp.9-17
    • /
    • 1994
  • Effect of Newtonian and non-Newtonian oils on minimum ol film thickness in engine journal bearing were investigated at various oil viscosities. The influence of oil viscosity and engine operating conditions on minimum oil film thickness of main bearing and con-rod bearing was examined. Minimum oil film thickness for Newtonian oils increased uniformly with kinematic viscosity. But the correlation between kinematic viscosity and minimum oil film thickness was very poor for non-Newtonian oils. According to the straight-line regression analysis for non-Newtonian oils, high temperature high shear viscosity at 1 $1{\times}10^6Sec^{-1}$, $150^{\circ}C$ increase the coefficient of determination from 0.41 to 0.77. Con-rod bearing showed better correlation between minimum oil film thickness and engine operating conditions than main bearing.

  • PDF

Determination of Thin Film Thickness by EDS Analysis and its Modeling (EDS 분석과 모델링에 의한 박막두께 측정 방법에 관한 연구)

  • Yun, Jae-Jin;Lee, Won-Jong
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
    • /
    • v.24 no.8
    • /
    • pp.647-653
    • /
    • 2011
  • In this study, a method to measure the thickness of thin film by EDS (energy dispersive spectroscopy) is suggested. We have developed a model which calculates the thickness of thin film from the characteristic x-ray intensity ratio of the elements in thin film and substrate by considering incident electron beam energy, x-ray generation curve, backscattering and absorption of x-ray, take-off angle of x-ray and tilt angle of the sample. We obtained the relation curve between the film thickness measured experimentally and the x-ray intensity ratio of elements. The film thicknesses calculated from the model agrees quite well with those measured experimentally. Therefore, the thin film thickness can be measured rapidly and accurately by using the model developed in this study and the x-ray intensity ratio obtained in EDS analysis.

A Study on the Change in the Film Thickness of Ball Bearing in Starved EHL (윤활유 부족 상태에서의 볼 베어링 유막 두께 변화에 대한 연구)

  • Jung, SoonBi;Lee, Bora;Yu, YongHun;Cho, YongJoo
    • Tribology and Lubricants
    • /
    • v.33 no.3
    • /
    • pp.119-125
    • /
    • 2017
  • In this study, we perform a numerical analysis to predict the film thickness and lubrication regions for a thrust ball bearing under different operating conditions. Film thinning and replenishment affect the film thickness in starved lubrication. As the inlet meniscus position is brought to the edge of the Hertz contact, the thin film thickness is calculated as starved equation. We use a film replenishment model to determine the recovery film thickness between rolling elements. We use a hydrodynamic model to describe film recovery, that results from the effects of surface tension. In this model, we consider the surface tension gradient in fluid depression as the driving force for fluid recovery. We use Fourier transform method to determine the time-dependent depth of depressed oil. We calculate the change in the central film thickness graphically by using the recovery equation in starved elastohydrodynamic lubrication(EHL) under operating conditions that include numbers of balls, sliding velocity, applied force, and ambient film thickness. We evaluate the degree of starvation by using the distance from the center of the contact area to the meniscus position. Parched lubrication, a phenomenon where the film thickness decreases consistently, occurs at the severe condition. We determine optimal values with respect to the numbers of balls, and sliding velocity. The investigation can contribute to the design operating conditions for proper lubrication.

Optimum Design of a Liquid Film Thickness Measurement Device Using Electric Conductance for Impingement Liquid Film (충돌 액막 분석을 위한 전기전도 액막 두께 측정장치 최적설계)

  • Lee, Hyeongwon;Lee, Hyunchang;Kim, Taesung;Ahn, Kyubok;Yoon, Youngbin
    • Journal of Sensor Science and Technology
    • /
    • v.27 no.6
    • /
    • pp.386-391
    • /
    • 2018
  • To analyze the film cooling in a liquid rocket engine, it is necessary to understand the characteristics of the wall-impingement liquid film. We designed an optimal two-dimensional device for measuring the thickness of the liquid film thickness. This device quantitatively measures the liquid-film thickness distribution. In previous liquid-film thickness measuring devices, the liquid film was formed over the entire area of the sensor. However, its formation depended on injection conditions. To compensate for this, optimal resistors are selected. Additionally, saturation variations with partial saturation are analyzed. Furthermore, calibration using the enhanced plate method is conducted with improvements in spatial resolution. The device designed here can be used to analyze the properties of an impingement liquid film with a slit injector. This study can be used for film-cooling analysis in liquid rocket engines.

Effect of Clear Coat Film on Appearance Characteristics in Car Refinishing (클리어 도막이 자동차 보수도장 외관특성에 미치는 영향)

  • You, Chang-Bae
    • Transactions of the Korean Society of Automotive Engineers
    • /
    • v.19 no.1
    • /
    • pp.32-37
    • /
    • 2011
  • In car refinishing, the paint film characteristics of clear coat play an important role in appearance quality. Thus, Primarily in this research, the variance of brightness with the change of the thickness of paint film is investigated. Besides, as changing the thickness of paint film, the correlation between surface leveling(which is one of appearance characteristics) is investigated in this research. Throughout this investigation, we come to know that the increase of clear coat paint film thickness leads the improvement of appearance characteristics within specific range of thickness. Furthermore, the fact that too thick paint film does not increase the brightness or appearance characteristic any more is known. The optimum thickness of clear coat film for the best and appearance characteristics is derived from this research and more efficient way of determining optimum thickness of paint film is found. Particularly, haze value and waviness have more influence on vividness than brightness. Throughout all experiments, the appearance characteristics are much better at painted horizontally than vertically. These results are derived due to the facts that to obtain the same paint film thickness at painted vertically with painted horizontally is difficult and the way of vertical painting is different from horizontal painting. Therefore, the improvement of vertical painting and horizontal painting are required.

Measurement Feasibility Assessment of Coating Film Thickness using Dual Sensor (이중센서를 이용한 코팅막 두께 측정 가능성 평가)

  • 김주현;김성렬;김정욱;김화영;안중환
    • Proceedings of the Korean Society of Precision Engineering Conference
    • /
    • 2004.10a
    • /
    • pp.78-81
    • /
    • 2004
  • A technical performance of the coating depends greatly on the thickness of painting film or coating film. Therefore the confirmed report of the technique to measure accurately is essential to the coating film thickness for the assessment about a coating quality performance. In this paper, two gap sensors - eddy current gap sensor and capacitance gap sensor - which has a different operating principle were used to measure the thickness of a nonmagnetic substance coating film such as paint, enamel or ceramic that was coated on the metallic material. A capacitance gap sensor was used to measure the distance between the sensor head and a coating film and an eddy current gap sensor to measure the distance between the sensor head and a base metal. Then the thickness of a coating film was obtained by the difference of two measurement value. At this result, the suggested dual sensor can measure an arbitrary film thickness to be coated on a base metal as the measurement value of coating thickness exists accurately within the 2% error.

  • PDF