• 제목/요약/키워드: Porthole-die

검색결과 41건 처리시간 0.019초

Prediction of Welding Pressure in the Non Steady State Porthole Die Extrusion of Al7003 Tubes

  • Jo, Hyung-Ho;Lee, Jung-Min;Lee, Seon-Bong;Kim, Byung-Min
    • International Journal of Precision Engineering and Manufacturing
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    • 제4권3호
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    • pp.36-41
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    • 2003
  • This paper describes a numerical analysis of a non-steady state porthole die extrusion, which is useful for manufacturing long tubes with a hollow section. Materials divided through several portholes are gathered within a chamber and are then welded under high pressure. This weldability classifies the quality of tube products and is affected by process variables and die shapes. However, porthole die extrusion has been executed based on the experience of experts, due to the complicated die assembly and the complexity of metal flow. In order to better assist the design of die and to obtain improvement of productivity, non-steady state 3D FE simulation of porthole die extrusion is required. Therefore, the objective of this study is to analyze the behavior of metal flow and to determine the welding pressure of hot extrusion products under various billet temperatures, bearing length, and tube thickness by FE analysis. The results of FE analysis are compared with those of experiments.

포트홀 형상이 컨덴서 튜브 직접 압출 공정 및 금형 탄성 변형에 미치는 영향 (The Effect of Porthole Shape on Elastic Deformation of Die and Process at Condenser Tube Extrusion)

  • 이정민;김병민;조훈;조형호
    • 한국소성가공학회:학술대회논문집
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    • 한국소성가공학회 2003년도 춘계학술대회논문집
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    • pp.315-318
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    • 2003
  • Recently, condenser tube which is used for a cooling system of automobiles is mainly manufactured by the conform extrusion but this method is inferior as compared with direct extrusion in productivity per the unit time and in the equipment investment. Therefore, it is essential for the conversion of direct extrusion with porthole die. The direct extrusion with porthole die can produce condenser tube which has the competitive power in costs and qualities compared with the existing conform extrusion. This study is designed to evaluate metal flow, welding pressure, extrusion load tendency of mandrel deflection that is affected by variation of porthole shape in porthole die. Estimation is carried out using finite element method under the non-steady state. Also this study was examined into the cause of mandrel fracture through investigating elastic deformation of mandrel during the extrusion.

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포트홀 다이를 이용한 개량된 Al7003 중공압출재의 접합압력결정 (Determination of Welding Pressure in the Porthole Die Extrusion of Improved Al7003 Hollow Section Tubes)

  • 정충식;조형호;김병민
    • 한국소성가공학회:학술대회논문집
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    • 한국소성가공학회 2000년도 추계학술대회 논문집
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    • pp.74-77
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    • 2000
  • Porthole die extrusion has a great advantage in the forming of hollow section tubes difficult to produce by conventional extrusion with a mandrel on the stem. Because of the complicated structure of die assembly, extrusion process as a forming of hollow section tubes has been investigated experimentally Therefore, analytic approaches that are useful in profitable die design and in the improvement of productivity are inevitably demanded Welding strength is affected by many parameters, which are such as extrusion ratio, extrusion speed, die shape, porthole number, bearing length, billet temperature and mandrel shape. In this paper, the parameters, which are such as billet temperature, bearing length and tube thickness, are examined. The welding pressures are examined through 3D simulation of non steady state and compared with experimental results.

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영역분할에 의한 격자세분화기법을 사용한 철도차량 마루부재 압출공정의 3차원 유한요소해석 (Three-Dimensional Finite Element Analysis for Hollow Section Extrusion of the Underframe of a Railroad Vehicle Using Mismatching Refinement with Domain Decomposition)

  • 박근;이영규;양동열;이동헌
    • 소성∙가공
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    • 제9권4호
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    • pp.362-371
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    • 2000
  • In order to reduce weight of a high-speed railroad vehicle, the main body has been manufactured by hollow section extrusion using aluminum alloys. A porthole die has utilized for the hollow section extrusion process, which causes complicated die geometry and flow characteristics. Design of porthole die is very difficult due to such a complexity. The three-dimensional finite element analysis for hollow section is also an arduous job from the viewpoint of appropriate mesh construction and tremendous computation time. In the present work, mismatching refinement, an efficient domain decomposition method with different mesh density for each subdomain, is implemented for the analysis of the hollow section extrusion process. In addition, a modified grid-based approach with the surface element layer is utilized lot three-dimensional mesh generation of a complicated shape with hexahedral elements. The effects of porthole design are discussed through the simulation for extrusion of an underframe part of a railroad vehicle. An experiment has also been carried out for the comparison. Comparing the velocity distribution at the outlet with the thickness variation of the extruded part, it is concluded that the analysis results can provide reliable measures whether the die design is acceptable to obtain uniform part thickness. The analysis results are then successfully reflected on the industrial porthole die design.

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포트홀 형상 변화를 고려한 Al 멀티셀 튜브 압출공정 해석 (FE Simulation of Extrusion Process for Al Multi Cell Tube According to the Changes of the Porthole Shape)

  • 이정민;김동환;조형호;김병민
    • 대한기계학회논문집A
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    • 제29권8호
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    • pp.1146-1152
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    • 2005
  • Recently, multi cell tube which is used for a cooling system of automobiles is mainly manufactured by the conform extrusion but this method is inferior as compared with direct extrusion in productivity per the unit time and in the equipment investment. Therefore, it is essential for the conversion of direct extrusion with porthole die. The direct extrusion with porthole die can produce multi cell tube which has the competitive power in costs and qualities compared with the existing conform extrusion. This study is designed to evaluate metal flow, welding pressure, extrusion load, tendency of mandrel deflection that is affected by variation of porthole shape in porthole die. Estimation is carried out using finite element method under the non-steady state. Also this study was examined into the cause of mandrel fracture through investigating elastic deformation of mandrel during the extrusion.

포트홀 다이를 이용한 중공튜브 압출 제품의 다이 챔버 형상에 따른 결합력에 대한 연구 (A Study on the Welding Pressure of Extrusion Processing of Hollow Tube Using the Porthole Die with the Different Chamber Shape)

  • 김민규;진인태;정영득;하만경
    • 한국소성가공학회:학술대회논문집
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    • 한국소성가공학회 2001년도 춘계학술대회 논문집
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    • pp.110-114
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    • 2001
  • The welding pressure in porthole die extrusion is affected by the shape of welding chamber. It is very important to increase the welding pressure when the tube is used particulary as the materials of hydroforming processing. The high circumferential stress of the tube would make the welding pressure increase during the porthole die extrusion. In order to increase the circumferential stress, it is necessary to make the billets pass through the narrow gap between the conical die and the conical mandrel. This paper describes the welding pressure by the experiments with the two types of the chamber. One of them is the chamber between the flat die and straight mandrel, and the other one is the chamber between the conical die and conical mandrel. The result of the experiments show that the conical chamber makes the welding pressure increase by the effect of the reducing the diameteres of tube.

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자동차용 범퍼 압출 공정의 유한요소해석 (Finite Element Analysis of the Extrusion Process for an Automobile Bumper)

  • 김광희;윤문철
    • 한국기계가공학회지
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    • 제4권1호
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    • pp.24-29
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    • 2005
  • The development of an aluminum bumper is required in order to reduce the weight of the automobile. An porthole die extrusion process is simulated by the finite element method in order to develop the aluminum bumper which is manufactured by hollow section extrusion. The general-purpose finite element analysis software is used. The developed analysis method can be applied to the optimization of the porthole die extrusion process for the aluminum bumper.

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포트홀 다이 압출방식에 의한 AI7003 튜브의 접합강도예측 (Prediction of Welding Pressure in the Non Steady state Porthole Die Extrusion of AI7003 Tubes)

  • 조형호;이상곤;이선봉;김병민
    • 한국정밀공학회지
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    • 제18권7호
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    • pp.179-185
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    • 2001
  • Porthole die extrusion is profitable to manufacture long tube with hollow section. The material through portholes is gathered within chamber and welded under high pressure. This weldability which classifies the quality of tube product is affected by several variables and die shape. But, porthole die extrusion has been executed on the experience of experts due to the complicated die assembly and complexity of metal flow. Analytic approaches that are useful in profitable die design and in the improvement of productivity are inevitably demanded. Therefore, the objective of this study is respectively to analyze the behavior of metal flow and to determine welding pressure of hot extrusion product according to the various billet temperature, bearing length and tube thickness by FE analysis and its results are compared with tube expanding tests.

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맨드렐이 있는 포트홀 압출의 소성유동에 관한 연구 (A Study on the Plastic Flow for Porthole Extrusion with Mandrel)

  • 임헌조;한철호
    • 한국소성가공학회:학술대회논문집
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    • 한국소성가공학회 2000년도 추계학술대회 논문집
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    • pp.78-81
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    • 2000
  • In this study the plasic flow before welding stage in the cahamber is analyzed by FEM and experiments during the porthole extrusion process. The analysis is concerned with plastic flow in the port and welding chamber of rectangular hollow section extrusion through the porthole die with mandrell. Numerical simulation by finite element code to investigate the plastic flow is discussed for both tapered inlet and straight inlet chamber. To visualize the flow in extrusion process split dies and punches are designed and manufactred by wire EDM. Experiments are carried out by using the plasticine as a model material at room temperature. The theoretical predictions are reasonable agreements with experimental results in the welding lines and the deformed profiles.

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영역분할에 의한 불일치 격자세분화 기법을 이용한 중공형 압출공정의 설계 및 해석 (Design and Analysis of Hollow Section Extrusion using Mismatching Refinement with Domain Decomposition)

  • 박근;양동열
    • 대한기계학회논문집A
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    • 제24권4호
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    • pp.1016-1023
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    • 2000
  • The present work is concerned with three-dimensional finite element analysis of the hollow section extrusion process using a porthole die. The effects of related design parameters are discussed through the finite element simulation for extrusion of a triply-connected rectangular tubular section. For economic computation, mismatching refinement, an efficient domain decomposition method with different mesh density for each subdomain, is implemented. In order to obtain the uniform flow at the outlet, design parameters such as the hole size and the hole position are investigated and compared through the numerical analysis. Comparing the velocity distribution with that of the original design, it is concluded that the design modification enables more uniform flow characteristics. The analysis results are then successfully reflected on the industrial porthole die design.