• Title/Summary/Keyword: Bending process

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A Study of Bending Process for Development of Subframe by Hydroforming (일체화 성형 서브프레임 개발을 위한 벤딩 공정의 영향성 연구)

  • 서창희;이우식;김헌영;임희택
    • Proceedings of the Korean Society for Technology of Plasticity Conference
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    • 2003.05a
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    • pp.262-265
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    • 2003
  • In the present study, subframe was developed using hydroforming technology. The manufacturing process for subframe consists of tube bending, pre-forming and hydroforming. The effects of bending process for manufacturing hydroformed subframe were researched. And the variables of bending process were studied by FEM simulation. The bending method is rotary draw bending that is the most popular, cost-effective bending method for thin walled tubes.

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A Study on the U-bending of Rectangular Hollow Tube by the Eccentric Extrusion and Bending Process (편심압출굽힘가공법에 의한 사각형 단면을 가진 중공 튜브제품의 U형굽힘가공에 관한 연구)

  • Kim, Jin-Hoon;Jin, In-Tai
    • Transactions of Materials Processing
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    • v.7 no.5
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    • pp.496-504
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    • 1998
  • The eccentric extrusion and bending process for the forming of the curved rectangular hollow tube is newly developed. Generally the bending process of hollow tube is the secondary process followed by the extrusion process of the hollow tube from the round billet. So many defects such as wrinkling and the difference of wall thickness can be happened during the secondary bending process. In order to avoid the defects the new process named as "the eccentric extrusion and bending process" is suggested and applied to the U-bending of rectangular hollow tube. In this paper the kinematically admissible velocity field between the dies surface and the internal plug boundary surface s developed for the curving velocity. By the using of this curving velocity field the curvature of extruded products can be calculated with the parameters such as eccentricity dies length friction constant aspect ratio.

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Analytic Factor Effects Analysis of Bending Process of Double Pipe for Tube-Hydroforming using Experimental Design (실험계획법을 이용한 튜브 하이드로 포밍용 이중관 벤딩 공정의 해석적 요인 효과 분석)

  • Shim, D.S.;Jung, C.G.;Seong, D.Y.;Yang, D.Y.;Park, S.H.;Kim, K.H.;Choi, H.H.
    • Proceedings of the Korean Society for Technology of Plasticity Conference
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    • 2007.05a
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    • pp.310-313
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    • 2007
  • This paper covers finite element simulations to evaluate the bending limit of double pipe for tube-hydroforming. The tube-hydroforming process starts with a straight precut tube. The tube is often prebent in a rotary draw bending machine to fit the hydroforming tool. During the bending the tube undergoes significant deformation. So forming defects such as wrinkling, thinning and flattening are generated in the tube. Consequently we analyzed the effect of process parameters in rotary draw bending process and searched the optimized combination of process parameters to minimize the forming defects using orthogonal arrays. The characteristic to evaluate the effects of the process parameters is the bending angle which wrinkling is generated, we define the bending angle at that time as bending limit. Of many process parameters, the process parameters of the bending process such as gab between inner and outer tube, boosting force, dimensions of mandrel were analyzed. And we observed the deformation modes of bent double pipe at specific bending angle in each parameter combination.

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Pre-Bending Analysis of Tie-Bar for Hydroforming (Hydroforming을 위한 Tie-bar의 예비굽힘성형 해석)

  • 강대철;전병희;성부용
    • Proceedings of the Korean Society of Machine Tool Engineers Conference
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    • 2000.10a
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    • pp.255-261
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    • 2000
  • Tube bending is one of the conventional manufacturing process. Recently, tube bending was highlighted in automotive industry by hydroforming. Tube hydroforming process is divided into pre-bending process and hydroforming process. It's initial state is very important in die cavity of first hydroforming process. So tube bending is important factor of the hydroforming process. In this paper, two pre-bending simulations, by a rotary draw bending machine and a bend die. This paper presents the simulation results in pre-bending process that is used to form an automotive part, tie-bar.

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Production of CO2 Laser Forming Machine for Bending of Sheet Metal Using the FE-Analysis (유한요소해석을 이용한 박판 벤딩용 CO2 레이저 성형기 제작)

  • Ko D.C.;Lee C.J.;Kim B.M.
    • Transactions of Materials Processing
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    • v.15 no.4 s.85
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    • pp.319-325
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    • 2006
  • The laser forming process is a new flexible forming process without forming tools and external force, which is applied to various fields of industry. Especially, applications of the laser forming process focused on cutting, welding and marking process. In this paper, the laser bending process of sheet metal which is heated by laser beam and formed by internal stress is simulated by using thermo elastic-plastic analysis model. Based on the result of FE-analysis, the laser bending machine is made to obtain reliable data for sheet bending. Under the same condition as FE-analysis, the laser bending experiment has been performed to ver 펴 the result of FE-analysis and good agreement has been obtained between FE-analysis and experiments. Additional laser bending experiments have been performed to evaluate the laser bending machine.

The Bending minimization of Joint Shat in Cross rolling

  • Park Joon Soo;Lim Seong Joo;Yoon Duk Jae;Choi Seogou
    • Proceedings of the Korean Society for Technology of Plasticity Conference
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    • 2003.10b
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    • pp.107-114
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    • 2003
  • Although cross rolling process has many advantages in forging a joint shaft, an automotive component of front axle unit, subsequent process is necessary to straighten its bending during forging process. In this paper the bending minimization of the joint shaft was studied to eliminate such an additional process. First of all, a characteristic diagram was used to find out factors affecting the bending of the shaft. Also design of experiments was utilized for estimating the influence of those factors. It was found that the phase angle, which is the difference in starting positions between upper and lower dies, was important to minimize the bending of joint shaft and die cooling is necessary to diminish the distribution of bending.

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Analysis and Process Design of Hot Pipe Bending Process With Small Bending Radius (작은 곡률반경 파이프 벤딩을 위한 열간 파이프 벤딩공정 해석 및 설계)

  • 류경희;김동진;김병민;이동주
    • Transactions of Materials Processing
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    • v.10 no.4
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    • pp.329-337
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    • 2001
  • The finite element simulation model and the program to calculate the reverse moment have been developed to analyse the stress state and deformation of pipe bending using local induction heating with small bending radius in this study. The reverse moment that is to be applied on the bending arm to control the wall thinning ratio of the bending outside to within a particular value. Even though the demand of pipes with small bending radius is increasing in power plants and ship buildings, the welded elbows are still widely used. The bending process with or without a reverse moment acting on the bending arm has been simulated. The reverse moments calculated from the developed program are in good agreement with the finite element simulations and the experiments.

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Applicability of the induction bending process to the P91 pipe of the PGSFR

  • Kim, Nak Hyun;Kim, Jong Bum;Kim, Sung Kyun
    • Nuclear Engineering and Technology
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    • v.53 no.5
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    • pp.1580-1586
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    • 2021
  • The application of induction bending processes to industrial pipe production is increasing. The induction bending process has the effect of reducing the number of inspections and preventing leaks by reducing the weld of the pipe. For these reasons, efforts have been made to apply an induction bending process to the pipe of the PGSFR under development in Korea and this is the first attempt in the SFR design. Since the PGSFR pipe has a relatively large diameter-to-thickness ratio, it is difficult to fabricate an induction bending pipe that meets the requirements. In addition, the material properties may change because the pipe heats to a very high temperature during the induction bending process. In this study, P91 pipes were fabricated by induction bending, and the results from analyzing the induction bending process' applicability to the P91 pipe of the PGSFR are examined. The various dimensional measurements of the pipes fabricated by the induction bending process were surveyed to determine whether the requirements of the ASME Code were met. The minimum thickness, ovality, and wall buckling measured in the fabricated pipe met all the requirements. Tensile, impact, and hardness tests at various locations of the fabricated pipe also satisfied the requirements.

A Study on the Extru-Bending Process of the Angle Product with non-Symmetric "ㄱ" Section (비대칭 "ㄱ" 단면 앵글제품의 압출굽힘 가공에 관한 연구)

  • 이경국;진인태
    • Proceedings of the Korean Society for Technology of Plasticity Conference
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    • 2003.10a
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    • pp.277-280
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    • 2003
  • It was investigated that the "ㄱ" type angle product could be bended with a curvature during extrusion by extru-bending process. The bending process for the "ㄱ" type angle product can be developed by the hot metal extru-bending machine with the two punches moving in the different velocity. Because of non-symmetry of product, it is important to design the ruled surface contour of dies cavity for the welding and bending with two billets. So it is designed that the multi-hole container has two non-symmetric holes and non-symmetric contour of dies entrance. The results of the experiment show that "ㄱ" type angle product can be bended by the extrusion process and that the curvature of the product can be controlled by the velocity of punch and that the defects such as the distortion of section and the thickness change of the product and the folding and wrinkling of the product did not happen after the bending processing by the extrusion bending machine.

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Forming Simulation of the Extrn-Bending Process of the Angle Product with '${\wedge}$' Section ([ '${\wedge}$' ]단면 앵글 구조재의 압출굽힘 가공에 관한 성형해석)

  • Lee K. K.;Jin I. T.
    • Proceedings of the Korean Society for Technology of Plasticity Conference
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    • 2004.10a
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    • pp.346-349
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    • 2004
  • In the previous experimental study about extru-bending of angle product, the bending of extruded angle products with the '${\wedge}$' section and 'ㄱ' section can be abtained by the hot metal extru-bending machine with the two punches moving in the different velocity. The bending curvature can be controlled by the different velocity of billets through the two-hole container. This paper describes simulation of extru-bending process by the difference of punch velocities. The result of the forming simulation by $DEFORM^{TM}-3D$ shows that the bending phenomenon at the die exit during extrusion can be abtained by the two punches moving in the different velocity. And it is possible to design extrusion dies and to control the curvature of product through the simulation of extru-bending process by analysis

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