• 제목/요약/키워드: Thickness Distribution

검색결과 2,295건 처리시간 0.032초

축대칭 초소성 블로성형의 두께분포 최적화를 위한 블랭크 설계 (Blank Design for Optimized Thickness Distribution for Axi-symmetric Superplastic Blow Forming)

  • 이정민;홍성석;김용환
    • 소성∙가공
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    • 제8권1호
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    • pp.92-100
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    • 1999
  • A procedure is proposed for determining the initial thickness distribution in oder to produce a specified final thickness distribution for the axisymmetrical superplastic blow forming processes. Weighted parameter is introduced to improve the simple ad $d_traction method and the initial blank thickness distribution is obtained by optimizing the weighted parameter. This method is applied to superplastic free bulging process with the uniform thickness distribution of final shape to confirm its validity. The optimum initial blank thickness distributions is obtained from arbitrary axisymmetrical superplastic blow forming processes such as dome, cone and cylindrical cup forming with die contact. It is concluded that the ad $d_traction method with weighted parameter is an effective method for an optimum blank thickness distribution design.esign.

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Comparision of Measurement and Calculation for Thin Films Thickness Distribution Coated by Magnetron Sputter System

  • Park, Jang-Sick;Oh, Ji-Young;Chun, Young-Hwan;Kim, Jong-Hwan;Lee, Seung-Lyul;Lee, Seung-Kil
    • 한국진공학회:학술대회논문집
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    • 한국진공학회 2011년도 제41회 하계 정기 학술대회 초록집
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    • pp.329-329
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    • 2011
  • We measured thin films thickness sputtered from Cu target in the magnetron sputter system. Thin films thickness is thin as integration power in target is large. Cu thin films thickness in 100 kWh integration watt was decreased by 20% when that of beginning was compared. But the shape of thin films thickness distribution was same. For the calculation of thin films thickness distribution in the 100 kWh, the angular distribution data sputtered of Cu particles is necessary when Ar ions enter to inclined erosion surface of Cu target. We used the relation results of sputter yield and main angular distribution of sputtering particles emitted from Cu target published by G. Betz.

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로봇 Off-Line Programming을 위한 페인트 스프레이 시뮬레이션 방법론 개발 (An Accurate and Efficient Method of the Spray Paint Simulation for Robot OLP)

  • 이승찬;송인호;범진환
    • 한국CDE학회논문집
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    • 제13권4호
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    • pp.296-304
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    • 2008
  • Recently, various attempts are being done to apply off-line programming system to field of paint robot. But most commercial simulation softwares have problems that are slow simulation speed and not support various painting paramenters on simulation. This paper proposes enhanced paint simulation method for off-line programming system. For these, this method used the mathematical model of flux field from a previous research. The flux field has the flux distribution function, which reflects on the feature of paint spray. A previous research derived this flux distribution function for an integral function and calculated paint thickness function for an integral function. But if flux distribution function is defined as an integral function, it is inadequate to use for real-time simulation because a number of calculation is needed for estimation of paint thickness distribution. Therefore, we defined the flux distribution function by numerical method for reducing a mount of calculation for estimation of paint thickness. We derived the equation of paint thickness function analytically for reducing a mount of calculation from the paint distribution function defined by numerical method. In order to prove proposed paint simulation method this paper compares the simulated and measured thickness. From this comparison this paper show that paint thickness distribution is predicted precisely by proposed spray paint simulation process.

원통형 딥드로잉 용기의 벽 두께 감소 최소화에 관한 실험적 연구 (Experimental Study on Minimizing Wall Thickness Thinning for Deep Drawing of Circular Shells)

  • 김두환
    • 소성∙가공
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    • 제7권4호
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    • pp.393-399
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    • 1998
  • For minimizing wall thickness thinning of circular shells, a new stamping technology, the deep draw-ing process combined with ironing is approached and investigated. The design requirements for the deep drawing shells are to keep the optimum wall thickness with max. 10 percent thickness thinning of the initial blank thickness, to make uniform thickness strain distribution for the wall of circular shell and to improve the shape accuracy for the roundness and concentricity. In order to check the validity and effectiveness of proposed work, a sample process design is applied to a circular shell needed for a 4multi-stepped deep drawing. Through experiments, the variations of the thickness strain distribution in each drawing process are observed. Also a series of experiments are performed to investigate optimum process variables such as the geometry of tooling, radius and drawing rate. In particular, the advantage of current approach with ironing is shown in contrast to the conventional deep drawing process. From the results of proposed method, the optimum value of process variables are obtained, which contribute more uniform thickness strain distribution and better quality in the drawn product.

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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.

슬릿 노즐 내부 압력 분포와 코팅 박막 두께 균일도 간의 상관관계 연구 (Study on Correlation Between the Internal Pressure Distribution of Slit Nozzle and Thickness Uniformity of Slit-coated Thin Films)

  • 김기은;나정필;정모세;박종운
    • 반도체디스플레이기술학회지
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    • 제22권4호
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    • pp.19-25
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    • 2023
  • With an attempt to investigate the correlation between the internal pressure distribution of slit nozzle and the thickness uniformity of slot-coated thin films, we have performed computational fluid dynamics (CFD) simulations of slit nozzles and slot coating of high-viscosity (4,800 cPs) polydimethylsiloxane (PDMS) using a gantry slot-die coater. We have calculated the coefficient of variation (CV) to quantify the pressure and velocity distributions inside the slit nozzle and the thickness non-uniformity of slot-coated PDMS films. The pressure distribution inside the cavity and the velocity distribution at the outlet are analyzed by varying the shim thickness and flow rate. We have shown that the cavity pressure uniformity and film thickness uniformity are enhanced by reducing the shim thickness. It is addressed that the CV value of the cavity pressure that can ensure the thickness non-uniformity of less than 5% is equal to and less than 1%, which is achievable with the shim thickness of 150 ㎛. It is also found that as the flow rate increases, the average cavity pressure is increased with the CV value of the pressure unchanged and the maximum coating speed is increased. As the shim thickness is reduced, however, the maximum coating speed and flow rate decrease. The highly uniform PDMS films shows the tensile strain as high as 180%, which can be used as a stretchable substrate.

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군속도 변화를 이용한 배관 두께 측정 (Estimation of the Pipe Thickness using the Variation of the Group Velocity)

  • 한승희;황종명;이장명
    • 로봇학회논문지
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    • 제5권1호
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    • pp.32-40
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    • 2010
  • This paper proposes the technique of estimating the pipe thickness using the measured group velocity. To measure the group velocity from the accelerometer data in the frequency domain, Wigner-Ville distribution is utilized, which interprets the waveform of the shock wave. Using this measured group velocity, this paper proposes the technique to estimate the thickness of pipes with the impact on the pipe. The group velocity is estimated by the modeling correlation between the group velocity and the thickness of the pipe based on the propagation velocities. The correlation model between thickness and group velocity has been proved through the real experiments. The measured group velocity in the frequency-domain is the maximum at the center frequency of the bending waves in the modeling of the group velocity. In addition to these, a smoothing technique for analyzing lamb wave Wigner-Ville distribution has been introduced to improve the reliability of the data acquisition.

충돌 제트 속도 분포를 고려한 액막의 두께와 속도 특성 (Characteristics of Thickness and Velocity of the Liquid Sheet Formed by Two Impinging Jets Considering Jet Velocity Profile)

  • 추연준;강보선
    • 한국분무공학회지
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    • 제12권2호
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    • pp.79-85
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    • 2007
  • In this study, the effect of jet velocity profile on the thickness and velocity of the liquid sheet formed by two impinging low speed jets was investigated. To predict the distribution of thickness and velocity of liquid sheet theoretically, the jet velocity profile which was measured experimentally was adopted in addition to the constant jet velocity as well as Poiseuille's parabolic profile. For three cases, the distribution of thickness and velocity of liquid sheet was analytically predicted by solving conservation equations including stagnation point. The predicted results were compared with previous experimental results. The jet velocity profile definitely affected the resulting characteristics of liquid sheet. The distribution of thickness and velocity of liquid sheet was more close to the measured results compared with that which was predicted by the assumption of constant jet velocity.

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기본고유진동수 최대화 문제에 있어서 경계조건에 따른 판구조물의 최적두께 분포 (Optimum Thickness Distributions of Plate Structure with Different Essential Boundary Conditions in the Fundamental Frequency Maximization Problem)

  • 이상진;김하룡
    • 한국공간구조학회:학술대회논문집
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    • 한국공간구조학회 2006년도 춘계 학술발표회 논문집 제3권1호(통권3호)
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    • pp.227-232
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    • 2006
  • This paper investigate the optimum thickness distribution of plate structure with different essential boundary conditions in the fundamental natural frequency maximization problem. In this study, the fundamental natural frequency is considered as the objective function to be maximized and the initial volume of structures is used as the constraint function. The computer-aided geometric design (CAGD) such as Coon's patch representation is used to represent the thickness distribution of plates. A reliable degenerated shell finite element is adopted calculate the accurate fundamental natural frequency of the plates. Robust optimization algorithms implemented in the optimizer DoT are adopted to search optimum thickness values during the optimization iteration. Finally, the optimum thickness distribution with respect to different boundary condition

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GPR탐사를 통한 NATM터널(무근)라이닝의 두께 분포 및 배면상태 평가 (Assessment of NATM tunnel lining thickness and its behind state utilizing GPR survey)

  • 추진호;유창균;오영철;이인모
    • 한국터널지하공간학회 논문집
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    • 제21권5호
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    • pp.717-733
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    • 2019
  • 본 연구에서는 3개의 공용중인 NATM터널에서 수행된 정밀안전진단 GPR탐사 결과로 라이닝 두께분포 및 배면상태 특성을 분석하였다. 라이닝 천장에서 실시한 GPR 자료분석으로 라이닝 콘크리트와 1차지보재 사이에 공간이 대부분 존재하는 것으로 분석되었다. 다수의 라이닝 종단탐사로 분석된 횡단 두께의 좌 우 불균형은 8.6~253.5 mm로 확인되었으며 급격한 두께편차 주변에서 종방향균열 발생을 확인하였다. 라이닝 천단 중앙에서 실시된 종단 두께 분포는 3개의 적합도 검증을 통해 터널별 최적의 분포함수가 선정되었다. 종방향 라이닝 두께의 평균이 설계기준 이상인 경우 정규분포 및 이와 유사한 분포 특성을 나타내고 있으며, 설계두께 이하의 터널에서는 Gamma, Inverse Gauss분포함수가 해당터널의 라이닝을 대표하기 위한 최적함수로 적합할 것으로 판단하였다. NATM터널(무근) 라이닝의 두께분포는 터널의 상태평가 및 안전성평가를 전반적으로 분석하기 위한 중요한 지표가 될 수 있으며, 향후 기존의 일정한 설계 두께를 적용하기 보다는 GPR탐사를 반영한 라이닝의 현실적인 평가 방법의 연구가 필요할 것으로 판단된다.