• Title/Summary/Keyword: Axisymmetric Extrusion

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A Study on the Determination of Initial Biller for Axisymmetric Cold Forging Products Using Neural Networks (신경망을 이용한 축대칭 냉간 단조품의 초기 소재 결정에 관한 연구)

  • 김영호;배원병;박종옥
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 1994.10a
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    • pp.217-222
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    • 1994
  • This paper describes the determination of optimal initial billet size for axisymmetric cold forging products using neural networks. The determination of optimal initial billet size is very important in forging design and forming sequence design, because the result of such designs and forming load can be different by variable initial billet sizes. The forming difficulty has been defined as the degree of difficulty in forming by 3 process ' forward extrusion, backward extrusion and upsetting. By neural networks a forming difficulty can be determined with the ratio of shape and forming process. From the graph of maximum, minimum, and average forming difficulties by variable billet sizes, the optimal billet size can be determined. The initial billets of a solid part and a hollow part whichwas determined by this study are compared with the sequence drawing generated by the one of forming sequence design system.

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A Comparisonal Analysis Among the Processes of Piston -Pin Production (Piston-Pin 제작공정의 비교해석)

  • 김장군;장동환;황병복
    • Proceedings of the Korean Society for Technology of Plasticity Conference
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    • 1996.03b
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    • pp.130-137
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    • 1996
  • Several cold extrusion processes to produce an axisymmetric steel piston-pin are investigated for comparing each other. Two methods among four conventinal ones are selected to be simulated using the rigid-plastic finite element method. One of the both methods using a mechanical press has one stage process and the other utilizing a cold header applies a multi-stage process to produce a final product. Because the main process is a backward extrusion, the design criteria such as the backward extrusion ration and punch diameter to depth rationare ocnsidered. FEM analysis is performed mainly for strain distributin and load-stroke relationshis. Based on the results of preliminary simulatin, both process sequences are proved to have proper charicteristics suitable for each production method in terms of maximum load. Those simulation results will be a good design criteria in the future work to advance the manufacturing process.

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An Axisymmetric Finite Element Analysis of Hot Tube Extrusion for the design of Ceramic Dies (세라믹 금형설계를 위한 열간 튜브 압출의 축대칭 유한요소해석)

  • 강연식;양동열;정순길;이준근
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 1996.11a
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    • pp.882-886
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    • 1996
  • The use of ceramics for extrusion dies is limited since the modification of die design is difficult. In order to successfully apply the ceramic dies to extrusion dies, a better understanding of the process should be preceded. This study focuses on understanding the characteristics of the process. In the present study, a hot extrusion of tube with a mandrel is analyzed by ALE finite element method. In order to obtain the stress state of ceraminc dies, the elastic analysis of dies is also carried out.

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A Study on Optimal Design Rule for Forward Extrusion Die (냉간 단조용 전방압출금형의 최적구조 설계에 관한 연구)

  • Kim, C.H.;Kim, S.Y.;Kim, J.H.
    • Journal of Power System Engineering
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    • v.3 no.1
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    • pp.45-49
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    • 1999
  • Lots of products are made in various working conditions, depending on the size and the shape of them. Usually, at first, the die for new items had been designed on the basis of experience and know-how, and then modified through trial and error. At a die design stage most of drawings have been drawn manually. Recently some forging companies save design time by repeated utilization of standardized parts with registered data base. In this study the automated die design technique for forward extrusion of axisymmetric products is developed. A standardized die system is proposed from the investigation of ones employed frequently in the metal forming field and the design rules for cold extrusion die. A design example of forward extrusion die is given and discussed.

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FE Analysis of Three Dimensional Backward Extrusion Using the ALE description (ALE 묘사에 왜한 3차원 후방압출 해석)

  • 정상원;정용호;김규하;조규종
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 2002.05a
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    • pp.628-631
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    • 2002
  • This paper has executed FE-analysis to review the feasibility for developing the process, which produces the narrow-cubic type cans, using the Backward Impact Extrusion process instead of using current process, multi-stage deep drawing. Proposes an analysis method by applying ALE(Arbitrary Lagrangian-Eulerian) description to non-axisymmetric extrusion. which is appreciated as one of good solution to mesh distortion in case of the large deformation plasticity process that has mass flux, and considers the factors which affects forming-loads related to punch velocity and fulid status of material.

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An Axisymmetric Finite Element Analysis of Hot Tube Extrusion Using Ceramic Dies (세라믹 금형을 이용한 열간 튜브 압출의 축대칭 유한요소해석)

  • Kang, Yeon-Sick;Yang, Dong-Yol;Chung, Soon-Kil;Lee, June-Gunn
    • Transactions of Materials Processing
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    • v.7 no.1
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    • pp.72-80
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    • 1998
  • This study is concerned with the thermo-biscoplastic finite element analysis of hot tube extrusion through square dies with a mandrel. The problem is treated as a non-steady state and the ALE description is used due to abruptly turning flow at the die aperture. Since the contact heat transfer coefficient and the friction factor are required in the analysis experiments are also carried out to determine the values, In order to apply ceramics to an extrusion die the study is focussed on under-standing the characteristics of the process. The simulated results provide the useful informations such as metal flow temperature distribution stress state etc. The elastic analysis of the dies is carried out to obtain the stress state of the ceramic dies.

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Mismatching Refinement with Domain Decomposition and Its Application to the Finite Element Analysis of the Extrusion Process (영역분할에 의한 격자세분화 기법 및 압출공정의 유한요소해석에의 적용)

  • Park, Keun;Yang, Dong-Yol
    • Transactions of Materials Processing
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    • v.8 no.3
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    • pp.284-293
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    • 1999
  • The rigid-plastic finite element analysis requires a large amount of computation time due to its non-linearity. For economic computation, mismatching refinement, and efficient domain decomposition method with different mesh density for each sub domain, is developed. A modified velocity alternating scheme for the interface treatment is proposed in order to obtain good convergence and accuracy. As a numerical example, the axisymmetric extrusion process is analyzed. The results are discussed for the various velocity update schemes form the viewpoint of convergence and accuracy. The three-dimen-sional extrusion process with rectangular section is analyzed in order to verify the effectiveness of the proposed method. Comparing the results with those of the conventional method of full region analysis, the accuracy and the computational efficiency of the proposed method are then discussed.

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A study on the extrusion forming characteristics of construction materials with die and process parameters (금형 및 공정변수에 따른 층상복합재료의 압출성형 특성에 관한 연구)

  • Ko, Byung-Du;Lee, Ha-Sung
    • Design & Manufacturing
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    • v.7 no.1
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    • pp.11-18
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    • 2013
  • This paper presents the plastic inhomogeneous deformation behavior of bimetal composite rods during the axisymmetric and steady-state extrusion process through a conical die. The rigid-plastic FE model considering frictional contact problem was used to analyze the co-extrusion process with material combinations of Cu/Al. Different cases of initial geometry shape for composite material were simulated under different conditions of co-extrusion process, which includes the interference and frictional conditions. The main design parameters influencing on deformation pattern are diameter ratio of the composite components and semi-die angle. Efforts are focused on the deformation patterns, velocity gradient, predicted forming load and the end distance through the various simulations. Simulation results indicate that there is an obvious difference of forming pattern with various diameter ratio and semi-die angle. The analysis in this paper is concentrated on the evaluation of the design parameters on the deformation pattern of composite rod.

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A Study on the Prediection of Fatigue Life in the Axi-symmetric Extrusion Die (축대칭 압출금형의 피로수명예측에 관한 연구)

  • 안수홍;김태형;김병민;최재찬;조해용
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 1994.10a
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    • pp.235-239
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    • 1994
  • In this paper, the fatigue behaviour of typical axisymmetric forward extrusion die is investigated and extrusion process is analyzed by the rigid-plastic finite element method and elasto-plastic finite element method. To approach the crack problem involving crack initiation and propagation in extrusion die, LEFM(Linear Elastic Fracture Mechanics) is introduced and singular element which models stress.strain singularity in the crack tip vincity has been used to obtain an accurate stress intensityu factor values and other results. Form the displacement around the crack tip the stress intensity factor and the effective stress intensity factor at the beginning of the die inlet radius has been calculated. Applying proper fatigue crack propagation criterion such as Paris/Erdogan fatigue law to this data the angle and direction of fatigue crack growth has been simulated and these are compared with some experimental results. Using the computed crack growth rate, fatigue life of the extrusion die has been evaluated.

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A Comparisonal Anlaysis among the Processes of Gear Blank (기어 블랭크 성형공정의 비교 해석)

  • 최호준;김장군;황병복
    • Proceedings of the Korean Society for Technology of Plasticity Conference
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    • 1996.10a
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    • pp.174-184
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    • 1996
  • Two methods for cold extrusion processes to produce an axisymmetric steel gear blank are investigated for comparing each other. The "classical" forming method consisting of four operations is selected first to be simulated using the rigid-plastic finite element method and uses single-die presses. The other using a fully automated transfer headers can produce the final part without interannealing. The final products must be checked at the design criteria such as area reduction, the extrusion ratio and punch diameter to depth ratio, especially punch buckling by simulations. FEM analysis is performed mainly for strain distribution, both process sequences are proved to have proper charicteristics suitable for each production method in terms of maximum load. Those simulation results will provide good design criteria in the future work to advance the manufacturing process.

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