• 제목/요약/키워드: Forming Velocity

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Warm Formability Variation of AZ31 Sheet by Double Stage Forming Velocity (이단성형속도에 따른 AZ31판재 온간 성형성 변화)

  • Kim, H.K.;Kim, J.D.;Heo, Y.M.
    • Transactions of Materials Processing
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    • v.18 no.2
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    • pp.112-115
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    • 2009
  • Press forming of magnesium alloy sheet is conducted at elevated temperatures to improve the press formability due to its low formability at room temperature. At elevated temperatures, magnesium alloy sheet formability is known to be very sensitive to the strain rate. In this paper, warm deep drawing tests of magnesium alloy AZ31 sheet was conducted under double forming velocity as well as single forming velocity to examine the formability change by forming velocity profile. The observed formability improvement by double forming velocity was analyzed by using the finite element analysis.

An Upper-Bound Analysis of the Socket Forming Process (Socket Forming에 관한 상계해석)

  • Hwang, Bum-Chul;Hong, Seung-Jin;Bae, Won-Byong
    • Journal of the Korean Society for Precision Engineering
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    • v.17 no.8
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    • pp.151-156
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    • 2000
  • A kinematically-admissible velocity field is proposed to determine the forming load the average extruded length and the velocity distribution in the forward and backward extrusion process of a socket. Experiments are carried out with antimony-lead billets at room temperature using the rectangular punch and the hexagonal die. The theoretical predictions of the forming load and the average extruded length are in good agreement with the experimental results.

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Application of the explicit time integration finite element method to quasi-static metal forming problems (금속 성형 공정의 준정적 변형 예측을 위한 외연적 시간 적분 유한 요소법의 적용에 대한 연구)

  • Yoo, Y.H.;Yang, D.Y.
    • Journal of the Korean Society for Precision Engineering
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    • v.12 no.12
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    • pp.53-63
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    • 1995
  • In the analysis of metal forming problems, the explicit time integration finite element method, which does not have convergence problems, is frequently used. The present work is to assess the applicability of the explicit time integration finite element method to quasi-static metal forming problems. Compressing analyses of thin-walled tubes and solid cylinders are performed with different loading velocities. The computed buckled profiles of thin walled tubes are compared with the theoretical and experimental ones and it is found that at sufficiently low loading velocity, the explicit time integration finite element method accurately predict quasi-static buckled profiles. When loading volocity is increased, the computed buckled profiles of thin-walled tubes are very sensitive to loading velocity however the computed profiles of solid cylinders are less sensitive to loading velocity. In orther words, the geometrically self-constrained specimens like solid cylinders are less sensitive to loading velocity than the geometrically unconstrained specimens like thin-walled tubes. As a result, it is found that the geometrically self-constrained problems which include the greater part of metal forming problems can be efficiently analyzed with loading velocity control technique.

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Study on Spring-Back Effect according to Roll Gap and Forming Velocity of Roll Forming Process (롤 포밍 공정의 롤 갭과 성형속도에 따른 스프링 백 영향 연구)

  • Kim, Dong Hong;Yoon, Dae-Hwan;Seol, Sang-Seok;Jung, Dong Won
    • Journal of the Korean Society for Precision Engineering
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    • v.33 no.6
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    • pp.477-483
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    • 2016
  • The spring-back and bow phenomenon in the roll forming process are important factors regarding the accuracy of evaluation of production goods. The purpose of this study was to determine the influence of spring-back and bow phenomenon according to the main variables (forming velocity and roll gap). The material of the forming sheet was high tension steel (SPFH 590), which has been used commonly in recent years. In order to accurately measure the spring-back and bow phenomenon, the forming sheet was formed into a V-shape. The study was applied to OFAT (One Factor at a Time) experimentation, with respect to the experimental variables (the forming speed and the roll gap). In the experimental results, the forming speed had a small influence on the spring-back and bow phenomenon. However, the roll gap had a greater influence on the springback and the bow phenomenon, as opposed to the forming speed.

Development of Forming Equipment Using Electromagnetic Lorentz Force (전자기 로렌쯔력을 이용한 성형장비 개발)

  • Lee, H.M.;Ku, J.K.;Noh, H.G.;Song, W.J.;Ku, T.W.;Kang, B.S.;Kim, J.
    • Proceedings of the Korean Society for Technology of Plasticity Conference
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    • 2009.10a
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    • pp.313-317
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    • 2009
  • Electromagnetic forming(EMF) is a high-velocity forming process which uses electromagnetic Lorentz force. Advantages of this forming technique are improved formability, reduction in wrinkling, non-contact forming and applications of various forming process. But the application of electromagnetic forming technique is still limited in industry. Thus for continuous research and development of technique based on experiments, develop the forming equipment and carry out the forming experiments for validation of forming equipment.

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Development of Sheet Metal Forming Apparatus Using Electromagnetic Lorentz Force (전자기 로렌쯔력을 이용한 박판성형 장비 개발)

  • Lee, H.M.;Kang, B.S.;Kim, J.
    • Transactions of Materials Processing
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    • v.19 no.1
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    • pp.38-43
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    • 2010
  • Electromagnetic forming (EMF) method is one of high-velocity forming processes, which uses electromagnetic Lorentz force. Advantages of this forming technique are summarized as improvement of formability, reduction in wrinkling, non-contact forming and applications of various forming process. In this study, the EMF apparatus is developed. It is designed to be stored in 10 capacitors connected in parallel, each with a capacitance of $50{\mu}F$ and maximum working voltage of 5kV. The system has capacitance of $500{\mu}F$ and maximum stored energy of 6.25kJ. And EMF experiments are carried out to verify the feasibility of the EMF apparatus, which has enough forming force from the results of EMF experiment. In addition, peak current carrying a forming coil is predicted from theoretical background, and verified the predicted value compared with experimental value using the current measurement equipment. Consequently, EMF apparatus developed in this study can be applied to various EMF researches for commercialization.

A Study on the Flow Control Forming Process and Experiment Device of Drum Clutch for Automatic Transmission (자동변속기용 드럼클러치의 유동제어 성형공정 및 실험장치 개발 연구)

  • Park, Jong-Nam
    • Journal of the Korean Society of Manufacturing Process Engineers
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    • v.12 no.6
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    • pp.69-76
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    • 2013
  • This paper presents the development of the FCF method for the manufacturing of final products using numbers related to the minimum amount of work. The utilized product is a drum clutch, which is part of the transmission of an automobile. A double acting press is secured first and a prediction of the forming load on the practical material is made through an experiment with a plasticine model. Also, a finite element simulation using product shape and properties is performed, as well as a press experiment. A double acting press is manufactured that is suitable for a double acting experiment with a conventional hydraulic press(200 tons). A peripheral device for the press is additionally designed for experimental purposes. And, the press has as its essential points the drive speed, stroke control, etc., all of which influence the forming and is modified. Especially, a laser system is used for velocity measurement of two punches. The forming load of a practical material is predicted in order to derive a forming load formula for cold conditions on the basis of approximate similarity theory. Finite element analysis of the relative velocity ratio(RVR), etc., for most suitable flow defect(unfilling, etc.) prevention is achieved as well. The results are verified through a press experiment.

Process Sequence Design in Cold Forging of Constant Velocity Joint Housing (등속조인트 하우징의 냉간단조 공정설계)

  • 이진희;강범수;김병민
    • Transactions of the Korean Society of Mechanical Engineers
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    • v.18 no.9
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    • pp.2234-2244
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    • 1994
  • A process sequence of multi-operation cold forging for actual application in industry is designed with the rigid-plastic finite element method to form a constant velocity joint housing(CVJ housing). The material flow during the CVJ housing forming is axisymmetric until the final forging process for forming of ball grooves. This study treats the deformation as an axisymmetric case. The main objective of the process sequence design is to obtain preforms which satisfy the design criteria of near-net-shape product requiring less machining after forming. The process sequence design also investigates velocity distributions, effective strain distributions and forging loads, which are useful information in the real process design.

Optimization of the Dirve for Lineaer-Guide Press (직선가이드프레스 구동부의 최적화)

  • 이영섭;황병복
    • Transactions of Materials Processing
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    • v.9 no.2
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    • pp.171-178
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    • 2000
  • This paper is concerned with the optimization of the drive for linear-guide press which is one of mechanical presses. The design of linear-guide drive for a mechanical press is introduced and the drive for the linear-guide press is optimized for the improvement of load and velocity characteristics. As a result of optimization, the load capacity during stroke increases and the slide velocity decreases in working region, respectively. The new design could be suited to many applications in precision forming such as extrusion and the sheet metal-forming processes.

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Effect of Process Parameters in Electromagnetic Forming Apparatus on Forming Load by FEM (유한요소해석을 통한 전자기 성형장비 공정변수의 성형력에 미치는 영향)

  • Noh, Hak Gon;Park, Hyeong Gyu;Song, Woo Jin;Kang, Beom Soo;Kim, Jeong
    • Journal of the Korean Society for Precision Engineering
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    • v.30 no.7
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    • pp.733-740
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    • 2013
  • The high-velocity electromagnetic forming (EMF) process is based on the Lorentz force and the energy of the magnetic field. The advantages of EMF include improved formability, wrinkle reduction, and non-contact forming. In this study, numerical simulations were conducted to determine the practical parameters for the EMF process. A 2-D axis-symmetric electromagnetic model was used, based on a spiral-type forming coil. In the numerical simulation, an RLC circuit was coupled to the spiral coil to measure various design parameters, such as the system input current and the electromagnetic force. The simulation results show that even though the input peak current levels were at the same level in each case, the forming condition varied due to differences in the frequency of the input current. Thus, the electromagnetic forming force was affected by the input current frequency, which in turn, determined the magnitude of the current density and the magnetic flux density.