• Title, Summary, Keyword: Forward Extrusion

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A Study on the Forming Characteristics of Radial Extrusions Combined with Forward Extrusion (전방압출과 연계된 레이디얼압출의 성형특성에 관한 연구)

  • 장용석;황병복
    • Transactions of Materials Processing
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    • v.9 no.3
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    • pp.242-248
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    • 2000
  • This paper is concerned with the family of parts that generally feature a central hub with radial protrusions. Radial Extrusion is usually used in order to produce complex parts, which is combined with upsetting and/or forward and backward extrusion. Typical parts that fall into this category include cross pieces for universal joints, key-shaft type parts, tube fittings, and differential gears. In this paper, the forming characteristics of radial extrusion combined with forward extrusion is investigated by comparing the punch and mandrel loads. The design factors during radial extrusion combined with forward extrusion are applied to the simulation to see how much those factors have effect on the forming loads. The rigid-plastic FEM is applied to the simulation.

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A Study on the Forming Characteristics of Radial-Forward Extrusion Process (레이디얼-전방압출 공정의 성형특성에 관한 연구)

  • 황승규;이호용;황병복
    • Transactions of Materials Processing
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    • v.11 no.1
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    • pp.84-89
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    • 2002
  • This study is concerned with the analysis of the forming characteristics of radial-forward extrusion. Angle between radial and forward extrusion, gap height, and friction factor are considered as important design factors to affect forming characteristics in radial-forward extrusion. The rigid-plastic finite element method is adopted to analyze the effects of design factors on forming loads. The incremental rates of loads are nearly constant except the deformation zone from radial to forward extrusion. The smaller angle induces lesser force increment, therefore forming load increases as the angle increases. Maximum load also increases as gap-height decreases and friction factor increases.

Deformation Behaviour of Forward -Backward EXtrusion in Rotary Forging Process (회전단조 공정에서 전-후방 압출 특성에 관한 연구)

  • 최석우;윤덕재;임성주;나경환
    • Proceedings of the Korean Society for Technology of Plasticity Conference
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    • pp.54-61
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    • 1995
  • Simultaneous forward-backward extrusion upsetting has been carried out by ratray forging. Two materials has been used commericaly 6.61 aluminium ally and 0.2% steel. The effects of working conditions ; spiral feed ; initial aspect ration of specimen and lubricating condition on the backward and forward extrusion were clarified. The extrusion length increases a sthe aspect rationof the specimen increases, the backward extrusion lengthbeing relatively larger than the forward one. The effects of the spiral feed and the material on the extrusion lengthis remarkably large for the large spiral feed.

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Numerical and Experimental Investigation on the Tube Forming in the Radial-Forward Extrusion (레이디얼-전방압출에서 튜브성형에 관한 해석 및 실험)

  • 고병두;장동환;최호준;황병복
    • Journal of the Korean Society for Precision Engineering
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    • v.20 no.12
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    • pp.168-175
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    • 2003
  • In this paper, the tube forming by radial-forward extrusion is analyzed by numerical simulation and experiments. The paper discusses the effects of process variables such as gap height, relative gap width and die corner radius on tube forming. The influence of deformation patterns of flange in radial extrusion on forward extrusion for tube forming is investigated and summarized in terms of the maximum forming force and hardness variations along the extrusion path. Furthermore the external defects are shown experimentally during the forming operation. Based on finite element analysis in conjunction with experimental test in Al alloy, analysis is performed for important parameter combination in order to reduce forming defects. Eventually, the process parameters for safe forming are suggested in order to reduce the forming defects.

Numerical and Experimental Investigation on the Tube Forming in the Radial-Forward Extrusion

  • Ko Beong-Du;Jang Dong-Hwan;Choi Ho-Joon;Hwang Beong-Bok
    • International Journal of Precision Engineering and Manufacturing
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    • v.6 no.2
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    • pp.26-33
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    • 2005
  • In this paper, the tube forming by radial-forward extrusion is analyzed by numerical simulation and experiments. The paper discusses the effect of process variables such as gap height, relative gap width and die comer radius on tube forming. The influence of deformation patterns of flange in radial extrusion on forward extrusion for tube forming is investigated and summarized in terms of the maximum forming force and hardness variations along the extrusion path. Furthermore the external defects are shown experimentally during the forming operation. Based on finite element analysis in conjunction with experimental test in Al alloy, analysis is performed for important parameter combination in order to reduce forming defects. Eventually, the process parameters for safe forming are suggested in order to reduce the forming defects.

Forming Characteristics of Magnesium Alloy in Cup-Rod Combined Extrusion Process (AZ31B 마그네슘 합금의 Cup-Rod 복합압출 성형특성 연구)

  • Yoon, D.J.;Kim, E.Z.;Cho, C.D.
    • Proceedings of the Korean Society for Technology of Plasticity Conference
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    • pp.70-73
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    • 2007
  • The forming characteristics of cup-rod combined extrusion process were investigated with process parameter change. Simultaneous forward rod extrusion and backward cup extrusion was conducted with magnesium alloy, AZ31B. Process parameters such as forward extrusion ratio, backward extrusion ratio, and working temperature were controlled in a specific region and the effects of the parameter change were examined. Surface crack was developed in a certain state of the process parameters combination. The crack-free forming limit of the alloy in the combined process was disclosed by the parameter study. The microstructures of the initial and extruded workpieces were observed.

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Characteristics of Forming toad in Forward and Backward Can Extrusion Processes (전ㆍ후방 캔 압출공정의 성형하중특성)

  • Choi H. J;Ham B. S;Ok J. H;Shim J. H;Kim S. H;Hwang B. B
    • Transactions of Materials Processing
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    • v.13 no.8
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    • pp.689-695
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    • 2004
  • This paper is concerned with the analysis of the forming load characteristics of a forward-backward can extrusion process. The analysis in this paper is extended to the selection of press frame capacity for producing efficiently final product at low cost. The possible extrusion processes to shape a forward-backward can part with different outer diameters are categorized to investigate quantitatively the forming load, forming energy and maximum pressure exerted on the die-material interface. The categorized processes are composed of combined and/or some basic extrusion processes. After the analysis of the forming load characteristics, the frame capacity of press suitable for a selected process could be determined along with securing the load capacity and with considering productivity. In addition, it is also suggested that different load capacities be selected for different dimensions of a part such as the wall thickness in forward direction. The work in this paper could be a good reference for analysis of complex extrusion and selection of proper frame capacity of press to achieve low production cost and thus high productivity.

A Study on Optimal Design Rule for Forward Extrusion Die (냉간 단조용 전방압출금형의 최적구조 설계에 관한 연구)

  • Kim, C.H.;Kim, S.Y.;Kim, J.H.
    • Journal of the Korea Society For Power System Engineering
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    • v.3 no.1
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    • pp.45-49
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    • 1999
  • Lots of products are made in various working conditions, depending on the size and the shape of them. Usually, at first, the die for new items had been designed on the basis of experience and know-how, and then modified through trial and error. At a die design stage most of drawings have been drawn manually. Recently some forging companies save design time by repeated utilization of standardized parts with registered data base. In this study the automated die design technique for forward extrusion of axisymmetric products is developed. A standardized die system is proposed from the investigation of ones employed frequently in the metal forming field and the design rules for cold extrusion die. A design example of forward extrusion die is given and discussed.

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A Study on the Effect of Process Parameters to Mechanical Property in Forward Extrusion of Milli-size Cylindrical Pin (밀리 단위의 원형핀 전방압출에 있어서 공정인자가 기계적 성질에 미치는 영향 연구)

  • 심경섭;김용일;이용신;김종호
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • pp.797-801
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    • 2003
  • The mechanical properties such as shear strength and the hardness of milli-size products that manufactured for various process parameters by forward extrusion using square dies are investigated. Shear strength test is implemented for the observation of relation between vickers hardness and shear strength in the interface of head and shaft part of a stepped pin. When the extrusion ratios of pure aluminum and pure copper billets increase, the hardness on both the surface and the center line of a pin also increase, especially the hardness on the surface is shown to be a little higher than on the center. The existence of knock-out pad in extrusion die caused hardness increase in the interface of a extruded pin. As compared shear strength with hardness of a pin, the approximated linear relations are suggested in this study.

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Deformation History of Product during Forward Extrusion Process (전방압출 공정에서 제품 변형 이력)

  • 이강희;박용복
    • Transactions of Materials Processing
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    • v.10 no.1
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    • pp.75-79
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    • 2001
  • The study has been performed for the relation between die and product during forward extrusion by the experiment. Stains of the die have been given by the simple experiment using the strain gauge located at the outer surface of the die. The history of the deformation of the die and the product has been given by the experiment and Lame's formula. The inner pressure of the die causes the deformation of die that affects the accuracy of dimension as well as shape of the product. The product with accurate dimension and shape can be obtained by analysing elastic deformation of the die during the process. The deformation of the die during metal forming process has been usually predicted by the experience of industrial engineer or finite element analysis. But it is difficult to predict the dimension of the product at unloading and ejected states. In the present study, useful results for the deformation history of the die and the product were obtained through the experiment and Lame's formula in forward extrusion which can be applied to the die design for the product with accurate dimension.

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