• Title, Summary, Keyword: Hydro-Piercing

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A study on deformation characteristics of tube hydro-piercing process (하이드로 피어싱에서의 변형 특성 연구)

  • 최성기;안익태;문영훈
    • Proceedings of the Korean Society for Technology of Plasticity Conference
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    • pp.237-240
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    • 2003
  • Deformation surrounding the hole in the tube during the hydro-piercing process has been investigated in this study. The tube is expanded and internally pressurized between upper and lower dies, and a piercing punch is driven forcefully through a cross passage in the die and through the wall of the tube. The pressurized fluid within the tube provides support to the wall of the tube during a piercing step to form a hole in the tube having less deformation surrounding the hole in the tube. The deformation area may be fully retracted to a substantially flat form or partially retracted to a countersunk form. In this study, a mathematical model that can predict deformation surrounding the hole has been proposed and experimentally verified by actual hydro-piercing test.

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Improvement of Connection Force in Hydro-Embedding Process Through the Rotational Piercing of the Connection Element (하이드로 임베딩시 연결요소의 회전을 통한 체결력 개선 연구)

  • Kim, Bong-Joon;Kim, Dong-Kyu;Kim, Dong-Jin;Moon, Young-Hoon
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.30 no.12
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    • pp.1503-1508
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    • 2006
  • To increase the applicability and productivity of hydroforming process, hydro-embedding process was developed by combining the hydro-forming process with embedding process simultaneously. It is necessary in the automotive parts to form hollow bodies with connection elements which combine one part with another. The hydro-embedding process is embedding the connection element hydraulically during the operating steps of the hydroforming. In this study, technique of rotational piercing is added on the existing hydro-embedding to increase the connection force of hydro-embedded element. To estimate the feasibility of new trial process, integrated researches on the hydro-embedding process technology have been performed by analyzing the deformed mode of the tubes and the optimal process parameters for various shapes of the connection elements.

Analysis of Deformation Surrounding the Pierced Hole in the Tube Hydro-Piercing Process (하이드로 피어싱된 튜브 부위의 변형해석)

  • 최성기;김동규;문영훈
    • Transactions of Materials Processing
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    • v.13 no.2
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    • pp.154-159
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    • 2004
  • Deformation surrounding the hole in the tube during the hydropiercing process has been investigated in this study. The tube is expanded and internally pressurized between upper and lower dies, and a piercing punch is driven forcefully through a cross passage in the die and through the wall of the tube. The pressurized fluid within the tube provides support to the wall of the tube during a piercing step to form a hole in the tube having less deformation surrounding the hole in the tube. The deformation area may be fully retracted to a substantially flat form or partially retracted to a countersunk form. In this study, a mathematical model that can predict deformation surrounding the hole has been proposed and experimentally verified by actual hydropiercing test.

Analysis on Roll Over in the Tube Hydro-Piercing Process (튜브 하이드로 피어싱시 롤 오버의 실험적 분석)

  • Choi, Sung-Ki;Ahn, Ick-Tae;Moon, Young-Hoon
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.28 no.7
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    • pp.992-998
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    • 2004
  • During the tube hydropiercing, the region adjacent to the pierced hole will be deformed and will be drawn away from the die block as the punch advances through the wall of the tube. The deformation in the region may range from a substantially flat form to a countersunk form, so called rollover. In this study, the effects of material properties, shape of piercing punches, roundness of tube surface and internal pressure within the tube during piercing on the rollover have been investigated experimentally. The results provide the quantitative variation of rollover at given hydropiercing parameters, and a relationship between the deformed radius and the rollover caused by the deformation has been established.

A study on the hydro-embedding technology in the tube hydroforming process (하이드로포밍 공정을 이용한 무용접 부품체결 기술개발에 관한 연구)

  • 김동규;박광수;안익태;한수식;문영훈
    • Proceedings of the Korean Society for Technology of Plasticity Conference
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    • pp.241-244
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    • 2003
  • The productivity of hydroforming process can be increased by combining pre-forming process and post-forming process such as the bending, piercing and the embedding process. Therefore in this study, integrated studies on the hydro-embedding technology have been performed by analyzing the deformed mode of the tubes and the optimal process parameters. In the case of the embedding test the characteristics of the embedded parts, such as the shape of the screw tip, screw thread and shape of thread were investigated at various process conditions. To measure the clamping force between the embedded part and the tube, special measuring device was used.

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Finite Element Analysis of the Hydro-mechanical Punching Process (정수압을 이용한 홀 펀칭공정의 유한요소 해석)

  • Yoon J.H.;Kim S.S.;Kim E.J.;Park H.J.;Choi T.H.;Lee H.J.;Huh H.
    • Transactions of Materials Processing
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    • v.15 no.3
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    • pp.220-225
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    • 2006
  • This paper investigates the characteristics of a hydro-mechanical punching process. The hydro-mechanical punching process is divided into two stages: the first stage is the mechanical half piercing in which an upper punch goes down before the initial crack is occurred; the second stage is the hydro punching in which a lower punch goes up until the final fracture is occurred. Ductile fracture criteria such as the Cockcroft, Brozzo and Oyane are adopted to predict the fracture of sheet material. The index values of ductile fracture criteria are calculated with a user material subroutine, VUMAT in the ABAQUS Explicit. The hydrostatic pressure retards the initiation of a crack in the upper region of the blank and induces another crack in the lower region of the blank during the punching process. The final fracture zone is placed at the middle surface of the blank to the thickness direction. The result demonstrates that the hydro-mechanical punching process makes a finer shearing surface than the conventional one as hydrostatic pressure increases.

Studies on the Shape Optimization of Connecting Element for Hydro-Embedding (하이드로 임베딩시 체결용 연결요소의 형상 최적화 연구)

  • Kim B. J.;Kim D. K.;Kim D. J.;Moon Y. H.
    • Transactions of Materials Processing
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    • v.14 no.9
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    • pp.756-763
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    • 2005
  • The applicability and productivity of hydroforming process can be increased by combining pre- and post-forming processes such as the bending, piercing and embedding process. For the fabrication of automotive parts, the hollow bodies with connecting nuts are widely used to connect parts together. Hollow body with connecting nuts has been conventionally fabricated by welding nuts or screwing in autobody screws. It requires multiple steps and devices fur the welding and/or screwing Therefore in this study, hydro-embedding process that combines the hydraulic embedding of connecting element(nut) with hydroforming process is investigated. Studies on the hydro-embedding technology have been performed to optimize the shape of the connecting element by analyzing the deformed mode of the embedded tube The effects of the shape of the screw tip, screw thread and shape of thread on the connection force between the tube and the connecting element have been investigated to optimize the shape of connecting element. Finite element analysis has also been performed to provide deformation behaviors of the tube surrounding a hole produced by hydro-embedding.

Finite element study on the hydro-embedding process (유한요소 해석법을 이용한 하이드로 임베딩 공정연구)

  • Kim D. K.;Park K. S.;Kim D. H.;Moon Y. S.
    • Proceedings of the Korean Society for Technology of Plasticity Conference
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    • pp.206-209
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    • 2004
  • In the hydroforming process the number of process can be reduced by combining pre-forming process and post-forming process such as the bending, piercing and the embedding process. Integrated studies on the embedding manufacturing technology have been performed by analyzing the deformed mode of the tubes and the optimal process parameters. In this study, a simulation model that can prove clamping force between the clamping element and tube has been investigated by FEM. The characteristics of the embedded parts, such as the shape of the screw tip, screw thread and shape of thread were investigated at various clamping element conditions.

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