• Title/Summary/Keyword: Forging load

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A Study on Extrusion of Helical Gears by a Two-step Process (2단계공정을 이용한 헬리컬기어 압출에 관한 연구)

  • Jung, S.Y.;Park, J.H.;Kim, C.;Kim, C.H.;Choi, J.C.;Choi, S.H.
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 2002.10a
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    • pp.824-828
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    • 2002
  • Of all the many types of machine elements which exist today, gears are among the most commonly used. Many researches have been done to manufacture helical gears by cold forging and extrusion. Although cold forging and extrusion were applied to some bevel, spur, and helical gears, problems in connection with reducing forming load and tool life still make it difficult for the related methods to be commercialized. In this study, focusing on reducing load in forming helical gears, extrusion of helical gears by a two-step process is proposed. The process is composed of an extrusion step of spur gears used as preform and a torsion step of the preform to make helical gears. Upper-bound analysis for the two-step process is performed and compared with results of experiments. The newly proposed method can be used as an advanced forming technique to remarkably reduce the forming load and replace the conventional forming process of helical gears.

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Automated Forming Sequence Design System for Multistage Cold Forging Parts (다단 냉간단조품의 자동공정설계시스템)

  • Park, J.C.;Kim, B.M.;Kim, S.W.;Kim, H.K.
    • Journal of the Korean Society for Precision Engineering
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    • v.11 no.4
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    • pp.77-87
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    • 1994
  • This paper deals with an automated forming sequence design system by which designers can determine desirable operation sequences even if they have little experience in the design of cold forging process. The forming sequence design in the cold forging is very important and requires many kinds of technical and empirical knowledge. They system isproposed, which generates forming sequence plans for the multistage cold forging of axisymmtrical solid products. Since the process of metal forming can be considered as a transformation of geometry, treatment of the geometry of the product is a key in planning process. To recognize the geometry of the product section, section entity representation and primitive geometries were used. Section entity representation can be used for the calculation of maximum diameter, maximum height, and volume. Forming sequence for the part can be determined by means of primitive geometries such as cylinder, cone, convex, and concave. By utilizing this geometrical characteristics (diameter, height, and radius), the product geometry is expressed by a list of the priitive geometries. Accordingly the forming sequence design is formulated as the search problem which starts with a billet geometry and finishes with a given product one. Using the developed system, the sequence drawing with all dimensions, which includes the proper sequence of operations for the part, is generated under the environment of AutoCAD. Based on the results of forming sequence, process variables(strain, punch pressure, die inner pressure, and forming load) are determined.

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Numerical Evaluation of Backward Extrusion and Head Nosing for Producing a 6.75L Small Seamless AA6061 Liner (6.75L급 소형 AA6061 라이너의 후방압출 및 노우징 공정에 관한 해석적 연구)

  • Ku, T.W.;Kang, B.S.
    • Transactions of Materials Processing
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    • v.22 no.4
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    • pp.204-215
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    • 2013
  • As a pressure vessel, a small seamless aluminum liner with inner volume of about 6.75L is made from an initial billet material of AA6061-O. To produce the aluminum liner, warm forging including backward extrusion and head nosing was numerically simulated using a billet initially pre-heated to about $480^{\circ}C$. Compression tests on the billet material were performed at various temperatures and strain rates, and the measured mechanical properties were used in the numerical simulations. For the backward extrusion and the head nosing, the tool geometries were designed based on the desired configuration of the aluminum liner. Furthermore, the structural integrity of the tooling was evaluated to ensure adequate tool life. The seamless aluminum liner has an endurance limit of about 1.47MPa ($15Kg_f/cm^2$), estimated based on the required inner pressure. The results confirm that the small seamless aluminum liner of AA6061-O can be successfully made by using the two stage warm forging procedures without any bursting failures.

Development of LPI Vehicle Fuel Filter Housing (LPI 차량용 연료필터하우징 개발)

  • Hong, Byeong-Hoon;Park, Sung-Young
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.15 no.2
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    • pp.653-659
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    • 2014
  • Computer simulation has been performed to optimize cold forging process of automotive LPI fuel filter housing. A mold and the test product have been manufactured considering the strain and load distribution during the cold forging process. Also, fuel flow simulation has been performed to analyze flow characteristics of existing model and new model. Simulation result shows that two models have equivalent pressure drop. Compared with the mass of existing product, raw material reduction of 16 g and 30.5 g has been achieved from the upper and lower housing, respectively. Total mass reduction of the new housing was 46.5 g. Leak test and internal pressure test have been performed to verify the safety standard and test results were satisfactory.

Process Design in Cold Forging of the Backward and Forward Extruded Part (전.후방 압출품의 냉간단조 공정설계)

  • Min, G.S.;Choi, J.;Choi, J.C.;Kim, B.M.;Cho, H.Y.
    • Journal of the Korean Society for Precision Engineering
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    • v.14 no.8
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    • pp.57-64
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    • 1997
  • The process design of backward and forward extrusion of axisymmetric part has been studied in this paper. The important factors of cold forging process with complex geometry are the design of initial billet shape, the possibility of forming by one-stage operation and the determination of preform shapes, etc. Based on the systematic procedure of process sequence design, the forming operation of cold forged part is analyzed by the commercial finite element program, DEFORM. The design criteria are forming load, geo- metrical filling without defect and a sound distribution of effective strain in final product. It is noted that one step of preform operation is required to obtain the final product. Numerical result is compared with experi- mental one. It is found that the analyzed result is in good agreement with actual forming result.

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Study on Cold Forward Extrusion Formality Analysis along with Tool Entrance Angle of Helical Gear for Electronic Parking Brake Using Finite Element Analysis (유한요소해석을 이용한 전자식 주차브레이크용 헬리컬 기어의 금형 도입부 각도에 따른 냉간 전방압출 성형성 분석에 관한 연구)

  • Kim, Byeong Kil;Lee, Hyun Goo;Cho, Jae Ung;Jeong, Kwang Young;Cheon, Seong Sik
    • Journal of the Korean Society for Precision Engineering
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    • v.32 no.11
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    • pp.977-982
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    • 2015
  • This study uses finite element analysis to evaluate the forming load of tool entrance angle of the cold forward extrusion molding process of helical gear; this can replace the spur gear applied to the Electronic Parking Brake (EPB) system. A cold forging process is often used in the automobile industry as well as in various industrial machines due to its high efficiency. Finite element analysis is frequently used when interpreting results of the forging process. Formality was evaluated by calculating tooth profile filling rate of helical gear. Change in required forming load was investigated when the entrance angle of forward extrusion tool die was changed from $30^{\circ}$ to $60^{\circ}$, also by finite element analysis. We suggest suitable tool entrance angles.

A study on the three-dimensional upsetting of non-prismatic blocks considering different frictional conditions at two flat dies (상하면의 마찰이 틀린 비직각주 소재의 3차원 업셋팅에 관한 연구)

  • 김종호;류민형;양동열
    • Transactions of the Korean Society of Mechanical Engineers
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    • v.13 no.3
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    • pp.345-352
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    • 1989
  • Upsetting of non-circular blocks is characterized by the three-dimensional deformation with lateral sidewise spread as well as axial bulging along thickness. A kinematically admissible velocity field for the upsetting of prismatic or non-prismatic blocks is proposed which considers the different frictional conditions at the top and bottom surfaces of a billet. From the proposed velocity field the upper-bound load and the deformed configuration are determined by minimizing the total power consumption with respect to some chosen parameters. Experiments are carried out with annealed SM 15C steel billets at room temperature for different billet shapes and frictional conditions. The theoretical predictions both in the forging load and the deformed configurations are shown to be in good agreement with the experimental observations. Therefore, the velocity field proposed in this work can be used for the prediction of forging load and deformation in upsetting of prismatic or non-prismatic blocks, considering the different frictional conditions at two flat dies.

The study of adopting the hydroforming method in the front axle of the commercial vehicle (대형 상용차 앞차축 액슬 하이드로포밍 공법 적용 연구)

  • Jeon, D.H.;Kim, Y.G.;Na, S,M.;Park, D.S.
    • Proceedings of the Korean Society for Technology of Plasticity Conference
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    • 2008.10a
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    • pp.169-173
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    • 2008
  • This study is concerned with adopting the hydroforming method in the front axle of the commercial vehicle. Generally the front axle of the commercial vehicle is made bγ the several operations of press forging. This product supports the big weight of the vehicle and load. The weight of the press forging parts is also so more than it of the press parts of the passenger car. So, we have studied the hydroforming method to lessen the weight of the front axle of the commercial vehicle. To apply the hydroforming method in the commercial vehicle, we had to use the operation of reducing the diameter of the used tube prior to the hydorforming operation.

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An Analysis of Cold Foging at Final State Using Rigid-Plastic FEM (강소성 유한요소법을 이용한 냉간단조 공정의 최종단계 해석)

  • Choi, Y.;Jung, S.Y.;Kim, B.M.;Choi, J.C.
    • Transactions of Materials Processing
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    • v.8 no.1
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    • pp.108-115
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    • 1999
  • In this paper, the analysis of cold forging in final state has been performed by using rigid-plastic FEM. For the analysis, the geometry and flow stress of the workpiece are required. One method to obtain the geometry is measurement of that made from experimet. To evaluate the flow stress, average effective strain is calculated from the load-stroke diagram by using energy method. The numerical test performed to show the validity of propose method. The analysis of PFIR, the precision forging of spurgear with inside relif, is performed.

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A Comparative Study of the Incompressibility Constraint on the Rigid Plastic Finite Element Method (강소성 유한요소법에서 비압축성조건의 비교 연구)

  • 이상재;조종래;배원병
    • Transactions of Materials Processing
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    • v.8 no.1
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    • pp.47-56
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    • 1999
  • The governing functional in plastic deformation has to satisfy the incompressibility constraint. This incompressibility constraint imposed on velocity fields can be removed by introducing either Lagrange multiplier or the penalty constant into the functional. In this study, two-dimensional rigid plastic FEM programs using these schemes were developed. These two programs and DEFORM were applied in a cylinder upsetting and a closed die forging to compare the values of load, local mean stress and volume loss. As the results, the program using Lagrange multiplier obtained a more exact and stable solution, but it took more computational time than the program using the penalty constant. Therefore, according to user's need, one of these two programs can be chosen to simulate a metal forming processes.

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