• Title/Summary/Keyword: Forward Extrusion

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A Study on the Optimal die angle of the Torsional Forward Extrusion Process (비틀림 전방압출 공정의 최적다이각에 관한 연구)

  • Lee S. I.;Kim Y. H.;Ma Xiang
    • Proceedings of the Korean Society for Technology of Plasticity Conference
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    • 2002.11a
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    • pp.23-32
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    • 2002
  • The torsional forward extrusion is the process that is executed by punch travel and die rotation. The advantages of having the die rotation on this process are that forming load can be reduced and optimal die angle can be increased. This provides a possibility to extrude cold-worded material where a large extrusion force and die angle are required. Also, this process can improve the material properties owing to the high deformation and uniform strain distribution. The forming load and optimal die angle of this process are determined by the upper bound analysis using stream function and the optimization technique. To verify the theoretical result, we have carried out experiments and FE simulations using DEFORM3D.

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Limit Analysis of Axisymmetric Forward Extrusion (축 대칭 전방 압출의 극한 해석)

  • Kim, Byung-Min;Choi, In-Keun;Choi, Jae-Chan;Lee, Jong-Soo
    • Journal of the Korean Society for Precision Engineering
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    • v.8 no.3
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    • pp.93-104
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    • 1991
  • Limit analysis is based on the duality theorem which equates the least upper bound to the greatest lower bound. In this study, limit analysis of axisymmetric forming problem with workhardening materials is formulated by minimizing the upper bound functional and finite element program is developed for forward estrusion. Limit loads, velocity and flow line fields are directly obtained under various process conditions and deformation characteristics such as strains, strain rates and grid distortion are obtained from the optimum velocity components by numerical calculation. The experimental observation was carried out for extrusion and compared with computed results. The good agreement between theoretical and experimental results is shown that the developed programming is very effective for the analysis of axisymmetric extrusion.

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Forming Analysis and Design of Cold Gear Forging using 3D Finite Element Method (3차원 유한요소법을 적용한 냉간단조 기어 성형 해석 및 설계)

  • 송종호;김수영;임용택
    • Proceedings of the Korean Society for Technology of Plasticity Conference
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    • 2002.05a
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    • pp.108-111
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    • 2002
  • It is important to predict forming procedure for minimizing trial-and-error in the application of cold forging of gears. In this study, 3-dimensional simulations of cold forging processes of spur and bevel gear were carried out using finite element method to investigate the characteristics of the processes. From the simulation result it was found that incomplete teeth forming of spur gear was occurred with increase of teeth number in forging by forward extrusion. It can be reduced through division of material flows at the initial forming state using forward/backward combined extrusion.

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Investigation of the Final-Stage Forward Extrusion of Regular Polygonal-Shaped Bars From Circular Billets Using Square Die (평금형을 이용한 원형 소재에서 다각형바의 최종단계 전방압출에 관한 연구)

  • 김동권;조종래;배원병
    • Transactions of Materials Processing
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    • v.4 no.1
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    • pp.59-69
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    • 1995
  • A simple kinematically admissible velocity field is proposed to determine the final-stage extrusion load and the average extruded length in the square-die forward extrusion of regular polygonal-shaped bars from circular billets. From the proposed velocity field, the upper-bound extrusion load and the average extruded length are determined by minimizing the total power consumption with respect to four parameters. Experiments have been carried out with hard solder billets at room temperature. The theoretical predictions of the extrusion load are in good agreements with the experimental results and there is generally reason able agreement in average extruded length between theory and experiment.

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A Study on Process Improvement of Combined Extrusion with Aluminum Alloy 7075 (유한요소 시뮬레이션을 이용한 알루미늄 7075 복합 압출재에 대한 공정개선 연구)

  • 김진복;이지억;강범수
    • Proceedings of the Korean Society of Propulsion Engineers Conference
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    • 1996.05a
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    • pp.197-205
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    • 1996
  • A combined extrusion process studied here consists of forward and backward extrusion, and it is formed in single operation. The metal flow involved in the operation has appeared to be difficult to analyze accurately because of mixed directions of the flow. In this study, conventional two operations of a forward and a backward extrusions is transformed into one operation of mixed extrusion. A process designed by an industry expert is simulated by the rigid-plastic finite element method to investigate the metal flow and defects. In addition to the FEM simulation, experimental analysis has been carried out to confirm the design in industry, which includes material characterization, preliminary expriment, and whole experimental forming operation. The experimental results show that warm forming of extrusion is more desirable than cold working and hot forming in view of grain growth. Also two conditions of lubrication between workpiece and die has been investigated.

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Study on Cold Forward Extrusion Formality Analysis along with Tool Entrance Angle of Helical Gear for Electronic Parking Brake Using Finite Element Analysis (유한요소해석을 이용한 전자식 주차브레이크용 헬리컬 기어의 금형 도입부 각도에 따른 냉간 전방압출 성형성 분석에 관한 연구)

  • Kim, Byeong Kil;Lee, Hyun Goo;Cho, Jae Ung;Jeong, Kwang Young;Cheon, Seong Sik
    • Journal of the Korean Society for Precision Engineering
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    • v.32 no.11
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    • pp.977-982
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    • 2015
  • This study uses finite element analysis to evaluate the forming load of tool entrance angle of the cold forward extrusion molding process of helical gear; this can replace the spur gear applied to the Electronic Parking Brake (EPB) system. A cold forging process is often used in the automobile industry as well as in various industrial machines due to its high efficiency. Finite element analysis is frequently used when interpreting results of the forging process. Formality was evaluated by calculating tooth profile filling rate of helical gear. Change in required forming load was investigated when the entrance angle of forward extrusion tool die was changed from $30^{\circ}$ to $60^{\circ}$, also by finite element analysis. We suggest suitable tool entrance angles.

Application of the Visioplasticity Method to the Axisymmetric Bulk Deformation Processes (축대칭소성가공에 있어서의 변형가시화법의 응용에 대한 연구)

  • Bai, Duck-Han
    • Journal of the Korean Society for Precision Engineering
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    • v.2 no.2
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    • pp.31-42
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    • 1985
  • The metal flow and the strain distribution is investigated for the steady state and non-steady state bulk deformation processes by using an improved visioplasticity method which includes the effective smoothing scheme. The comparison of various smoothing schemes leads to the selection of the five- point least square smoothing method which is employed to reduce the measurement errors. As a steady state forming process experiments are carried out for axisy- mmetric forward extrusion through conical and curved dies of various area reduc- tions using Aluminum and steel billets. Axisymmetric backward extrusion is chosen for a nonsteady state forming process. In axisymmetric forward extrusion the results from visioplasticity show that the curved die of a fourth-order polynomial renders more uniform distribution of strain rates and strains. Higher reduction leads to greater strain rates at the outer side of the billet. The visioplastic observation for axisymmetric backward extrusion as a non-steady state deformation process shows the concentration of higher strain at the inner wall of the extruded product. The visioplastic results in forward extrusion are in agreement with the computed results by the finite element method. It is thus shown that the visio- plasticity combined with a smoothing technique is an effective method to determine the pattern and the distribution of strain rates and strains.

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The study on the flow defect of cold combined forward-backward extrusion product (${\cdot}$후방 압출 제품의 유동 결함에 관한 연구)

  • Hwang S. H.;Lee D. J.;Kim B. M.
    • Proceedings of the Korean Society for Technology of Plasticity Conference
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    • 1999.05a
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    • pp.79-82
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    • 1999
  • This paper presents a study of cold combined forward-backward extrusion product. The case of product with thin wall in piercing process occur defects of deformation and breakdown during piercing process and the center web of product with thin thickness cause flow defect. Such defect is made by the difference of material flow. Methods of the material flow control in the two directions and forming process to remove this flow defect is proposed. The effectiveness of the proposed methods is examined by comparison experiment and finite element simulation.

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Comparision between Forward Extrusion and Upsetting Process for Preform with Stepped Shape (단 달림 형상의 예비성형체 성형에 대한 전방압출과 업셋팅 공정의 비교)

  • Song D. H.;Park Y. B.;Kim M. E.
    • Proceedings of the Korean Society for Technology of Plasticity Conference
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    • 2000.10a
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    • pp.82-85
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    • 2000
  • In cold forging, the final product is usually given by multi-stage process and the preform with stepped shape can be manufactured through the various forging method. The forward extrusion and upsetting processes for preform with stepped shape have been analyzed by using the rigid-plastic finite element analysis code, InteFORM and compared for load and stroke according to ae reduction of weを An engineer should select the proper processes considering the capacity and the stroke of the corresponding press in the forging of the preform with stepped shape.

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