• 제목/요약/키워드: Cold Multi-Stage Forging

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Experimental Study on Multi-Stage Cold Forging for an Outer Race of a CV Joint (등속조인트용 외륜의 다단 냉간 단조공정에 관한 실험적 연구)

  • Kang, B.S.;Ku, T.W.
    • Transactions of Materials Processing
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    • v.23 no.4
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    • pp.221-230
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    • 2014
  • This study deals with a series of experimental investigations on multi-stage cold forging of an outer race used for a constant velocity (CV) joint with six inner ball grooves. The multi-stage cold forging, which consists of forward extrusion, upsetting, backward extrusion, and combined sizing-necking including ironing, was used to produce a prototype of the outer race. The cold forging tools such as forging punches and dies required in this multi-stage cold forging were also designed and fabricated. For the combined sizing-necking, especially, the longitudinally six-segmentallized punches were developed to easily eject from the necked inner groove of the outer race with consideration of the operating mechanism. Spheroidized SCr420H billet was used in the experimental study. To verify the suitability of the proposed process, the obtained parts were obtained from each forging operation, and the geometries were compared with the target dimensions. It was confirmed that the outer race with six inner ball grooves was well forged by adopting the proposed multi-stage cold forging, and the dimensional accuracy of the forged outer race matched well with the requirements.

Rigid-Plastic Finite Element Analysis of Multi-Stage Automatic Cold Forging Processes by Combined Analyses of Two-Dimensional and Three-Dimensional Approaches (2차원 및 3차원 연계해석을 통한 다단 자동냉간단조 공정의 강소성 유한요소해석)

  • Lee, M.C.;Joun, M.S.
    • Transactions of Materials Processing
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    • v.17 no.3
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    • pp.155-160
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    • 2008
  • We analyzed a sequence of multi-stage automatic cold forging processes composed of four axisymmetric processes followed by a non-axisymmetric process using rigid-plastic finite element based forging simulators. The forging sequence selected for an example involves a piercing process and a heading process accompanying folding or overlapping, which all make it difficult to simulate the processes. To reduce computational time and to enhance the solution reliability, only the non-symmetric process was analyzed by the three-dimensional approach after the axisymmetric processes were analyzed by the two-dimensional approach. It has been emphsized that this capability is very helpful in simulating the multi-stage automatic forging processes which are next to axisymmetric or involve several axisymmetric processes.

Rigid-Plastic Finite Element Analysis of Multi-Stage Automatic Cold Forging Processes by Combined Analyses of Two-Dimension and Three-Dimensional Approaches (2차원 및 3차원 연계해석을 통한 다단 자동냉간단조 공정의 강소성 유한요소해석)

  • Lee, M.C.;Joun, M.S.
    • Proceedings of the Korean Society for Technology of Plasticity Conference
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    • 2007.10a
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    • pp.195-200
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    • 2007
  • We analyzed a sequence of multi-stage automatic cold forging processes composed of four axisymmetric processes followed by a non-axisymmetric process using rigid-plastic finite element based forging simulators. The forging sequence selected for an example involves a piercing process and a heading process accompanying folding or overlapping, which all make it difficult to simulate the processes. To reduce computational time and to enhance the solution reliability, only the non-symmetric process was analyzed by the three-dimensional approach after the axisymmetric processes were analyzed by the two-dimensional approach. It has been emphsized that this capability is very helpful in simulating the multi-stage automatic forging processes which are next to axisymmetric.

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Multi-stage Cold Forging Process Design and Backward Extrusion Characteristics Evaluation of Serration Gear for Electronic Parking Brake (전자식 파킹 브레이크용 세레이션 기어의 냉간다단단조 공정 설계 및 후방 압출특성에 관한 평가)

  • Seo, Ju-Han;Choi, Jong-Won;Jung, Eu-Enn;Kang, Myungchang
    • Journal of the Korean Society of Manufacturing Process Engineers
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    • v.21 no.2
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    • pp.130-136
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    • 2022
  • Reducing production costs through net-shaped cold forging is an important aspect in the automobile industry. In this study, we intend to produce a net-shaped electronic parking brake (EPB) serration gear for automobiles, using multi-stage cold forging. These serrations are then assembled to the reduction gear of an EPB actuator. The forging process of the serrations and the cold forging design were verified through finite element analysis (FEA) in order to evaluate metal flow. The forging machine was selected by checking the load using FEA. Based on the FEA results, molds were designed, and parts were made using multi-stage cold forging to produce a net-shaped serration gear.

Process Modification and Numerical Simulation for an Outer Race of a CV Joint using Multi-Stage Cold Forging (등속조인트용 외륜의 다단 냉간 단조공정을 위한 공정개선 및 유한요소 해석)

  • Kang, B.S.;Ku, T.W.
    • Transactions of Materials Processing
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    • v.23 no.4
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    • pp.211-220
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    • 2014
  • The outer race of a constant velocity (CV) joint having six inner ball grooves has traditionally been manufactured by multi-stage warm forging, which includes forward extrusion, upsetting, backward extrusions, necking, ironing and sizing, and machining. In the current study, a multi-stage cold forging process is examined and an assessment for replacing and modifying the conventional multi-stage warm forging is made. The proposed procedure is simplified to the backward extrusion of the conventional process, and the sizing and necking are combined into a single sizing-necking step. Thus, the forging surface of the six ball grooves can be obtained without additional machining. To verify the suitability of the proposed process, a 3-dimensional numerical simulation on each operation was performed. The forging loads were also predicted. In addition, a structural integrity evaluation for the tools was carried out. Based on the results, it is shown that the dimensional requirements of the outer race can be well met.

Effectiveness Validation on Cold Multi-Stage Forging of Aluminum Inner Tie Rod Socket (알루미늄 이너 타이로드 소켓의 냉간다단단조 유효성 검증)

  • Park, Jae-Wook;Choi, Jong-Won;Jeong, Enn-Eun;Yoon, Il-Chae;Kang, Myungchang
    • Journal of the Korean Society of Manufacturing Process Engineers
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    • v.21 no.1
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    • pp.49-55
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    • 2022
  • Recently, the automobile industry has continued to demand lighter materials owing to international environmental regulations and increased convenience. To address this demand, aluminum parts have increased in popularity and are mainly developed and produced through hot forging and cold pressing. However, because this method has low yield and low production efficiency, a new manufacturing method is desirable. In this study, the water capacity efficiency of an aluminum inner tie rod socket was investigated using cold forging that provided a high yield and excellent production efficiency. Mechanical properties were derived through tensile testing of 6110A aluminum materials, and critical fracture factor and process analysis based on experimental data were carried out. The optimized process was applied as a prototype using cold multi-stage forging, and based on the derived results, the formability, productivity, and material efficiency of aluminum inner tie rod socket parts using this cold forging process was verified.

Multi-Stage Cold Forging Process Design with A* Searching Algorithm (탐색 알고리즘을 이용한 냉간 단조 공정 설계)

  • 김홍석;임용택
    • Proceedings of the Korean Society for Technology of Plasticity Conference
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    • 1995.10a
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    • pp.30-36
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    • 1995
  • Conventionally design for multi-stage cold forging depends on the designer's experience and decision-making. Due to such non-deterministic nature of the process sequence design, a flexible inference engine is needed for process design expert system. In this study, A* searching algorithm was introduced to arrive at the vetter process sequence design considering the number of forming stages and levels of effective strain, effective stress, and forming load during the porcess. In order to optimize the process sequence in producing the final part, cost function was defined and minimized using the proposed A* searching algorithm. For verification of the designed forming sequences, forming experiments and finite element analyses were carried out in the present investigation. The developed expert system using A* searching algorithm can produce a flexible design system based on changes in the number of forming stages and weights.

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Finite Element Analysis for Multi-stage Forging Process Design of Bolt with Nonaxisymmetric Washer Cam (비축대칭 와셔 캠 볼트의 다단 단조공정 설계를 위한 유한요소 해석)

  • Kim, Kwan-Woo;Kim, Yi-Tae;Kim, Wan-Jong;Cho, Hae-Yong
    • Journal of Advanced Marine Engineering and Technology
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    • v.32 no.4
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    • pp.585-595
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    • 2008
  • Process design of multi-stage forging for a bolt with nonaxisymmetric washer cam has been studied by using finite element method. For shape complexity of the bolt, it is impossible to manufacture in a single stage forging. To design multi-stage forging for the bolt the forging load and fiber flow of each step have been analyzed by using commercial finite element code DEFORM-3D. Simulated results have been compared with experimental ones. Multi-stage forging process has been designed with four stages. The workpiece should be eccentric shape until third forging stage. And then bolt head and washer of eccentrical shape is created in last stage. As a results, It was predicted that shape of product would be good and effective strain would be uniformly distributed in the product. Also, it was predicted whether defects would exist or not by reviewing the fiber flow.

Mold-design Verification of Ball Housing Insert Die in Non Processing Type Multi-stage Cold Forging (다단냉간단조 비가공 타입에서 볼하우징 인서트 다이의 금형설계 검증)

  • Hwang, Won-Seok;Choi, Jong-Won;Jung, Eu-Enn;Kang, Myungchang
    • Journal of the Korean Society of Manufacturing Process Engineers
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    • v.20 no.12
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    • pp.8-15
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    • 2021
  • Cold forging is a method in which molding is performed at room temperature. It has a high material recovery rate and dimensional precision and produces excellent surface quality, and it is mainly used for the production of bolted or housing products. The lifespan of cold forging molds is generally determined by the wear of the mold, plastic deformation of the mold, and fatigue strength. Cold forging molds are frequently damaged due to fatigue destruction rather than wear and plastic deformation in a high-temperature environment as it is molded at room temperature without preheating the raw material and mold. Based on the results analyzed through FEM, an effective mold structure design method was proposed by analyzing the changes in tensile and compressive stresses on molds according to the number of molds and reinforcement rings and comparing the product geometry and mold stress using three existing mold models.

Monitoring and Analysis on Die Loads in Multi-stage Cold Forging Process Using Piezo-Sensors (금형블록에 장착된 압조센서를 활용한 다단 냉간단조 공정의 모니터링 및 분석)

  • Kang, S.M.;Kang, K.J.;Yeom, S.R.;Lee, K.H.;Kim, J.Y.
    • Transactions of Materials Processing
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    • v.31 no.1
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    • pp.5-10
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    • 2022
  • In multi-stage cold forging process, to enhance the productivity and product quality, in-site process monitoring technique by implanting sensors such as piezo-sensor and acoustic emission sensor has been continuously studied. For accurate analysis of the process, the selection of appropriate sensors and implantation positions are very important. Until now, in a multi-state forging machine, wedge parts located at the end of punch-set are used but it is difficult to analyze minute changes in die block-set. In this study, we also implanted sensors to the die part (die spacer) and compared signals from both sensors and found that sensing signals from die part showed enhanced process monitoring results.