• Title, Summary, Keyword: Preform Design

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Preform Design of the Bevel Gear for the Warm Forging using Artificial Neural Network (신경망을 이용한 정밀 베벨기어의 온간단조 예비성형체 설계)

  • 김동환;김병민
    • Journal of the Korean Society for Precision Engineering
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    • v.20 no.7
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    • pp.36-43
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    • 2003
  • In this paper, the warm forging process sequence has been determined to manufacture the warm forged product for the precision bevel gear used as the differential gear unit of a commercial automobile. The preform shape of bevel gear influences the dimensional accuracy and stiffness of final product. So, the design parameters related preform shape such as aspect ratio and chamfer length having an influence the formability of forged product are analyzed. Then the optimal conditions of design parameters have been selected by artificial neural network (ANN). Finally, to verify the optimal preform shape, the experiments of the warm forging of the bevel gear have been executed. The proposed method can give more systematic and economically feasible means for designing preform shape in metal forming process.

Preform Design for the Sinter-forging Process of Arc-shaped Powdered Magnets (원호 형상을 가지는 분말자석 단조성형공정에서의 예비성형체 설계)

  • Kim, Seung-Ho;Lee, Choong-Ho;Huh, Hoon
    • Transactions of Materials Processing
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    • v.8 no.2
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    • pp.135-142
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    • 1999
  • Tube Process(TP) is one of the processes to produce permanent magnets. Advantage claimed for this process is that it can accmplish both densification and anisotropication in one step forming. This process is distinguished from other processes since it uses deformable tube for densification of powder magnets. TP has, however, difficulties in manufacturing permanent magnets from Nd-Fe-B green powder due to folding resulted from large height reduction and localized densification. Therefore, an adequate preform is necessary to reduce folding resulted from large height reduction and localized densification. Therefore, an adequate preform is necessary to reduce folding, lead magnets into almost desired final shape and get uniform densification. In this paper, preform design for TP is carried out without a deformable tube to investigate the behaviour of magnet sinter-forging. Preform design is accomplished to increase the effective magnet area with a near net shape and uniform densification.

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Design of Hexagonal Fitting Nut Preform Considering a Ductile Fracture (연성파괴를 고려한 6각 피팅 너트 예비성형체 설계)

  • 김동환;이정민;김병민
    • Transactions of Materials Processing
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    • v.13 no.4
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    • pp.359-364
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    • 2004
  • In the multi-stage former, a manufacture of hexagonal fitting nut was generated in a defective products about 70∼80% in the industry field. Products generated in defects manufactured to be a machining about 60%. Additional process increased a product cost and decreased a product rate. Therefore, it is important to predict and design a preform reducing defective products in the early stage of process design. So in the study Defects for manufacturing hexagonal fitting nut verified a cause through the finite element simulation. To reduce a defective generation. a preform designed and a designed preform verified through the finite element simulation. In conclusion, a generated defects when a hexagonal fitting nut manufactured should reduce if a round dimension of preform reduced and a part of opposition angle distributed in plenty a volume.

The Optimal Preform Design for Automotive Differential Bevel Gear (자동차용 차동 베벨기어의 최적 예비성형체 설계)

  • 김병민;김동환;정구섭
    • Transactions of the Korean Society of Automotive Engineers
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    • v.12 no.1
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    • pp.184-189
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    • 2004
  • In this paper, the warm forging process sequence has been determined to manufacture the warm forged product for the precision bevel gear used as the differential gear unit of a commercial automobile. The preform shape of bevel gear influences the dimensional accuracy and stiffness of final product. The aspect ratio and chamfer length are considered as design parameters to achieve adequate metal distribution in the finish forging operation. Then the optimal conditions of design parameters have been selected by artificial neural network (ANN). Finally, to verify the optimal preform shape, the experiments of the warm forging of the bevel gear have been executed. The proposed method can give more systematic and economically feasible means for designing the preform shape in metal forming process.

Design of Preform using equi-potential lines in Hot Forging (등전위면을 이용한 열간 단조에서의 예비형상 설계)

  • 이영규
    • Proceedings of the Korean Society for Technology of Plasticity Conference
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    • pp.71-74
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    • 2000
  • The equi-potential lines designed in the electric field are introduced to find the preform shape in axisymmetric hot forging. The equi-potential lines generated between two conductors of different voltages show similar trends of the minimum work paths between the undeformed shape and the deformed shape. Base on this similarity the equi-potential lines obtained by arrangement of the initial and final shapes are utilized for the design of preform and then the artificial neural network is used to find the range of initial volume and potential value of the electric field.

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Design of Preform in the Forging Process of the Ball-Joint Socket (볼조인트 소켓 단조 공정의 예비형상 설계)

  • Park C. H.;Lee S. R.;Shin H. K.;Yang D. Y.;Park Y. B.;Ahn B. G.;Kim Y. H.;Bae M. H.;Chung S. C.
    • Proceedings of the Korean Society for Technology of Plasticity Conference
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    • pp.224-227
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    • 2001
  • The preform design in metal forging plays a key role in improving product quality, such as ensuring defect-free property and proper metal flow. In industry, preforms are generally designed by the iterative trial-and-error approach, but this approach leads not only to significant tool cost but also to the down-time of the production equipment. It is thus necessary to reduce the time and the man-power through an effective method of perform design. In this paper, the equi-potential lines designed in the electric field are introduced to find the preform shape. The equi-potential lines obtained by the arrangement of the initial and final shapes are utilized for the design of the preform, and then applied for obtaining a fine preform in the foging process of the ball-joint socket.

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Preform Design Technique by Tracing The Material Deformation Behavior (재료의 변형거동 추적을 통한 예비형상 설계)

  • Hong J. T.;Park C. H.;Lee S. R.;Yang D. Y.
    • Proceedings of the Korean Society for Technology of Plasticity Conference
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    • pp.91-94
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    • 2004
  • Preform design techniques have been investigated in efforts to reduce die wear and forming load and to improve material flow, filing ratio, etc. In hot forging processes, a thin deformed part of a workpiece, known as a flash, is formed in the narrow gap between the upper and lower tools. Although designers make tools that generate a flash intentionally in order to improve flow properties, excessive flash increases die wear and forming load. Therefore, it is necessary to make a preform shape that can reduce the excessive flash without changing flow properties. In this paper, a new preform design technique is proposed to reduce the excessive flash in a metal forging process. After a finite element simulation of the process is carried out with an initial billet, the flow of material in the flash region is traced from the final shape to the initial billet. The region belonging to the flash is then easily found in the initial billet. The finite element simulation is then carried out again with the modified billet from which the selected region has been removed. In several iterations of this technique, the optimal preform shape that minimizes the amount of flash without changing the forgeability can be obtained.

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Preform Design Technique by Tracing the Material Deformation Behavior (재료의 변형거동 추적을 통한 예비형상 설계)

  • Hong J. T.;Park C. H.;Lee S. R.;Yang D. Y.
    • Transactions of Materials Processing
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    • v.13 no.6
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    • pp.503-508
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    • 2004
  • Preform design techniques have been investigated to reduce die wear and forming load and to improve material flow, filling ratio, etc. In hot forging processes, a thin deformed part of a workpiece, known as a flash, is formed in the narrow gap between the upper and lower tools. Although designers make tools that generate a flash intentionally in order to improve flow properties, excessive flash increases die wear and forming load. Therefore, it is necessary to make a preform shape that can reduce the excessive flash without changing flow properties. In this paper, a new preform design technique is proposed to reduce the excessive flash in a metal forging process. After a finite element simulation of the process is carried out with an initial billet, the flow of material in the flash region is traced from the final shape to the initial billet. The region belonging to the flash is then easily found in the initial billet. The finite element simulation is then carried out again with the modified billet from which the selected region has been removed. In several iterations of this technique, the optimal preform shape that minimizes the amount of flash without changing the forgeability can be obtained.

Process Design of Shaft Considering Effect of Preform and Eccentric Load on Cold Forging Product in Multistage Former of Horizontal Type (수평식 냉간 다단포머에서 예비성형체와 편심하중을 고려한 Shaft의 성형공정설계)

  • Park S. S.;Lee J. M.;Kim B. M.
    • Transactions of Materials Processing
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    • v.14 no.1
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    • pp.57-64
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    • 2005
  • This study deals with the cold forging process design for shaft in the main part of automobile motors with rectangular deep groove. In forging process, the accuracy and die lift is very important because it have influence on reduction of the production cost and the increase of the production rate. Therefore, it is necessary to develop the manufacturing process of shaft by cold forging., process variables are the cropped face angle of billet and the eccentric load of punch. The former is derived from cropping test, the latter is occurred by clearance between container and preform. Also, grooved preform select the process variable for decrease in punch deflection. We investigate that a deflection of punch and a deformation of preform to every process variables. Through this investigation, we suggest the optimal preform and process design, expect to be improved the tool life in forging process.

preform Design by Use of Spread Coefficient for Flange Forging (폭연신계수를 이용한 플랜지단조의 초기형상설계)

  • 김진영;박종진
    • Proceedings of the Korean Society for Technology of Plasticity Conference
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    • pp.157-166
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    • 1995
  • A large crank shaft for ship engine consists of several components, such as throw, jornal, pin and flange. These compoents are individually made by open-die forging followed by machining and they are thermally fitted to form the crankshaft. In the present investigation, it was attempted to design an optimum preform for the throw by use of the spread coefficient. The spread coefficient found in the literature was confirmed by comparison with experimental results using plasticine. However, the preform designed by the spread coefficient was unable to produce the final product. The reason was found that the spread coefficient differs distinctly for the magnitude of bite ratio. Therefore, another spread coefficient, especially for low bite ratios, was proposed and the preform was redesigned. It was found that the new preform was able to produce the final product.

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