• Title/Summary/Keyword: Forming Parameter

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Application of CAE Techinique for the Optimization of Press Forming Condition of Low Arm (로우암 프레스 성형 조건의 최적화를 위한 CAE 기술의 적용)

  • 김영석;이택근;김성태
    • Transactions of Materials Processing
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    • v.9 no.3
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    • pp.257-264
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    • 2000
  • In this study, optimization for press forming condition of low arm was performed with explicit dynamic FEM code, Pam-Stamp. FEM simulation was coupled with the Taguchi's experiment technique having three design variables - friction coefficient, plastic anisotropy parameter, and blank shape - which are chosen to be optimized. The simulation results were compared with those of experiment. We found out the change of blank shape among these three design variables is very effective in optimizing press forming condition of low arm. In addition, the modified blank shape shows high yield of slitting coil.

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Design of Cross Wedge Rolling Die for a Non-heat-treated Cold Steel using CAD and CAE (CAD/CAE를 이용한 냉간 비조질강용 회전전조 금형설계)

  • Lee H. W.;Yoon D. J.;Lee G. A.;Choi S.
    • Proceedings of the Korean Society for Technology of Plasticity Conference
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    • 2004.05a
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    • pp.400-403
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    • 2004
  • A non-heat기leafed steel does not need quenching and tempering processes that are called a heat treatment differently from conventional steel. Since the tensile strength of this steel is higher than 900MPa, a conventional forming process should be changed to incremental forming process such as a cross wedge rolling that requires lower load capacity than conventional ones. In this paper, the cold cross wedge rolling (CWR) die has been designed using CAD/CAE In order to produce near-net-shaped component of ball stud of non-heat-treated cold steel. Finite element analyses were applied in order to investigate process parameters of CWR. Results provide that the stretching angle and the forming angie at knifing zone in CWR process is important parameter to be the stable process under the low friction coefficient condition.

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A Study on Formability of Aluminum Sheet in Incremental Forming (점진성형에서 알루미늄 판재의 성형성에 대한 연구)

  • Park, Jong-Jin;Kim, Yung-Ho
    • Proceedings of the KSME Conference
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    • 2003.04a
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    • pp.1142-1147
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    • 2003
  • The formability of sheet metal appears better in incremental forming than in conventional forming. in this study, the effect of process parameters - tool type, tool size, feed rate, friction at the interface between tool and sheet, plane-anisotropy of sheet - on the formability was investigated by experiments and FEM analyses. it was found that the formability is improved when a ball tool of a particular size is used with a small feed rate and a little friction. Due to the plane anisotropy, the formability differs according to the direction of the tool movement. in this paper, details of the experimental procedures and the results obtained from the study are discussed.

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Effects of Blank Design factors on Stretch Flange Forming of the Tailored Blank Using Taguchi Method (다구찌법을 이용한 테일러드 블랭크의 신장플랜지 성형에 미치는 설계 인자의 영향 분석)

  • 백승엽;권재욱;이경돈
    • Transactions of Materials Processing
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    • v.9 no.4
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    • pp.339-347
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    • 2000
  • For the successful forming of tailored blank, it is important to control the deformation of the stretch flange mode, which is strong1y dependent upon the location of weld line and blank shape. In order to investigate the effects of tailored blank design factors on the stretch flange forming, we made the model die which can simulate stretch flange mode. Taguchi method was employed to analyze the sensitivity of blank design factors for the forming of tailored blank. From the results of experiment S/N ratios were calculated and using Variance Analysis, significance of parameters and optimal condition of each factors were extracted. Based on these analyses, the weld line height and the strength ratio and the arc center height were selected as effective parameter. The analysed result was practically applied for Side outer panel stamping process.

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Chemical Properties of Star Forming Galaxies in the Cluster Environment

  • Chung, Jiwon;Rey, Soo-Chang;Kim, Suk;Sung, Eon-Chang
    • The Bulletin of The Korean Astronomical Society
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    • v.37 no.2
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    • pp.88.1-88.1
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    • 2012
  • We utilize Sloan Digital Sky Survey DR7 spectroscopic data of ~340 star forming galaxies in the Virgo cluster to investigate their chemical properties depending on the environments. The chemical evolution of galaxies is linked to their star formation histories (SFHs), as well as to the gas interchange in different environments. In this sense, galaxy metallicity could be an observable parameter providing information on the impact of the environment on the galaxy SFH and/or the galaxy gas content. Thus, we derived gaseous metallicity (e.g., oxygen abundance) of star forming galaxies located in different regions of the Virgo cluster using well-known empirical calibrations. We also estimated their star formation rate (SFR) using H alpha luminosity. Inorder to investigate the chemical properties of these galaxies, we examined relations between various parameters: metallicity vs. luminosity, SFR vs. luminosity, and metallicity vs. cluster-centric radius. From our results, we discuss environmental effects of cluster to the chemical properties of star forming galaxies.

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Experimental and Numerical Analyses of Flexible Forming Process for Micro Channel Arrays of Fuel Cell Bipolar Plates (연료전지 분리판의 마이크로 채널 제작을 위한 가변성형공정의 실험적 및 수치적 연구)

  • Kim, H.S.;Shim, J.M.
    • Transactions of Materials Processing
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    • v.21 no.8
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    • pp.499-505
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    • 2012
  • The fuel cell is a very promising power generation system combining the benefits of extremely low emissions, high efficiency, ease of maintenance and durability. In order to promote the commercialization of fuel cells, a flexible forming process, in which a hyper-elastic rubber is adopted as a medium to transmit forming pressure, is suggested as an efficient and cost effective manufacturing method for fuel cell bipolar plates. In this study, the ability of this flexible forming process to produce the micro channel arrays on metallic bipolar plates was first demonstrated experimentally. Then, a finite element (FE) model was built and validated through comparisons between simulated and experimental results. The effects of key process parameters on the forming performance such as applied load and punch velocity were investigated. As a result, appropriate process parameter values allowing high dimensional accuracy without failure were suggested.

The Prediction of Interfacial Heat Transfer Coefficient According to Contact Time and Pressure in Forging and Casting Die Materials for the Hot Press Forming (핫프레스포밍용 주조, 단조 금형에 대한 시간과 압력에 따른 대류열전달계수의 예측)

  • Kim, N.H.;Kang, C.G.
    • Transactions of Materials Processing
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    • v.19 no.6
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    • pp.378-386
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    • 2010
  • Nowadays there has been great interest in using heat treated cast material for press dies due to several advantages like reduction in die production costs. However, in hot press forming processes H13 forged tool steel is mostly used. Cooling performance of dies in hot press forming processes is considered as an important factor of study and also the IHTC parameter between cast material die and sheet metal should be considered as an essential. In the present study, the IHTC was calculated for the sheet metal in the hot press forming process with cast and forged material dies. The temperature measurements were performed for the sheet metal, casting and forged material dies by applying various contact pressure in hot press forming. IHTC was calculated and studied by adopting the inverse heat convection method in DEFORM-2D. Each IHTC was considered as a function of contact time and contact pressure. The experimental data were compared with calculated data obtained from the proposed equation and references.

Tool Design and Numerical Verification for Thick Plate Forming of Hollow-Partitioned Steam Turbine Nozzle Stator (스팀 터빈용 중공 분할형 노즐 정익의 후판 성형을 위한 금형 설계 및 해석적 검증)

  • Kang, B.K.;Kwak, B.S.;Yoon, M.J.;Jeon, J.Y.;Kang, B.S.;Ku, T.W.
    • Transactions of Materials Processing
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    • v.25 no.6
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    • pp.379-389
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    • 2016
  • As a stator for steam turbine diaphragm, hollow-type nozzle stator to substitute for conventional solid one is introduced in this study. This hollowed stator can be separated into two parts such as upper and lower plates with large and curved surface area. This study focuses on thick plate forming process for the upper plate of the hollow-partitioned nozzle stator. First, to reduce forming defects such as under-cut and localized thinning of the deformed plate, and to avoid tool interruption between forming punch and lower die, tool design including the position determination of forming surfaces is performed. Uni-axial tensile tests are carried out using SUS409L steel plate with initial thickness of 5.00mm, and plastic strain ratio (r-value) is also obtained. Due to the asymmetric curved configuration of the upper plate, it is hard to adopt a series of blank holder or draw-bead, so the initial plate during this thick plate forming experiences unstable and non-uniform contact. To easy this forming difficulty and find suitable tool geometry without sliding behavior of the workpiece in the die cavity, two geometric parameters with respect to each shoulder angle of the lower die and the upper punch are adopted. FE models with consideration of 21 combinations for the geometric parameters are built-up, and numerical simulations are performed. From the simulated and predicted results, it is shown that the geometric parameter combinations with ($30^{\circ}$, $90^{\circ}$) and ($45^{\circ}$, $90^{\circ}$) for the shoulder angle of the lower die and the upper punch are suitably applied to this upper plate forming of the hollow-partitioned nozzle stator used for the turbine diaphragm.

Effect of the Design Parameter for Internal Spline Forming Using the Tube (중공축 내접 스플라인 성형을 위한 설계변수의 영향)

  • Wang, C.B.;Lim, S.J.;Park, Y.B.
    • Transactions of Materials Processing
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    • v.15 no.7 s.88
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    • pp.512-517
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    • 2006
  • In this paper, the cold extrusion process for internal spline forming using a thin and long tube has been analyzed by using a rigid plastic finite element code. The internal spline consists of 10 tooths. The cold extrusion process has been focused on the comparisions of load-stroke relation and filling states of the teeth according to design parameters. The design parameters involve extrusion ratio, extrusion angle and friction factor. The internal spline forming can cause the buckling and folding during the cold extrusion process because of using a thin and long tube. The optimum design parameters have been obtained through rigid-plastic finite elements analysis. The extrusion ratio and extrusion angle have great effects on the deformation characteristics of the cold extrusion process.

A Study on the Forming-analysis of Inner structured Design parameter (내부구조재의 설계변수에 따른 성형영향 분석)

  • Park J.H.;Choi D.S.;Jea T.J.;Kim H.J.
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 2005.06a
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    • pp.1547-1550
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    • 2005
  • ISB panel, inner structured of metal in two skin and bonded, has inner structures which have low relative density, stiffness and strength with low weight of make improvement for that purpose. A kind of Inner structures have various structure types. In this paper, we have studied the Forming Limit Diagram(FLD), thickness variation and stress strain to dimple structure of sheet by analysis of Dynaform and LS-Dyna.

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