• Transactions of Materials Processing
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• v.1 no.2
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• pp.40-51
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• 1992

냉간단조에 의한 새로운 헬리컬기어 성형공정이 제시되었다. 원형봉재로 부터 헬리컬기어를 압출함에 있어서 압출압력을 계산하기 위하여 상계정리를 적용하여 수치계산하고, 수치해석 결과와 압출하려는 기어의 금형을 설계 제작하여 실험한 결과를 비교 검토하고자 한다. 이론해석상 다이형상으로 인벌류트곡선을 사용한 이론해는 실험결과와 잘 일치하였다. 그리고, 다이의 형상을 평기어부와 헬리컬기어부의 이중구조로 된 신공정이 헬리컬기어부로만 된 사만타공정과 비교해서 금형강도를 향상시킴으로써 다이수명은 증가되었고, 자동차 변속기용으로 헬리컬기어는 KS 기어급수 4~5 급의 정밀도에 해당하는 기어를 가공했다. 이는 사만타공정의 정밀도 보다 향상된 결과를 얻었다.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 1998.03a
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• pp.94-99
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• 1998

In bulk metal forming processes prediction of tool life is very important for saving production cost and achieving good material properties. Generally the service life of tools in metal forming process is limited to a large extent by wear, fracture and plastic deformation of tools. In case of hot and warm forging processes, tool life depends on wear over 70%. In this study finite element analyses are applied to warm forging and hot forging by adopting suggested wear model. By comparision of simulation and real profile of die, suggested model is verified

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 1998.03a
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• pp.88-93
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• 1998

The service life of tools in metal forming process is to a large extent limited by wear, fatigue fracture and plastic deformation. In warm forging processes wear is the predominant factor for operating lives of tools. To predict tool life by wear, Archard's wear model is generally applied. Usually hardness of die is considered to be a function of temperature in Archard's wear model. But hardness of die is a function of not only temperature but also operating time of die. To consider softening of die by repeated operations, it is necessary to express hardness of dies by a function of temperatures and operating time. By experiment of reheating of dies, die softening curves were obtained. Finally modified Archard's wear model in which hardness of die was expressed as a function of main tempering curve was proposed.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2003.10a
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• pp.232-232
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• 2003

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 1995.06a
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• pp.158-164
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• 1995

진합정공 주식회사는 다단 성형기를 사용하여 자동차 부품이나 건축재 등을 냉간 단조로 생산하는 중소기업으로서, 수입에 의존하고 있는 각종 단조품들의 국산화와 고부가 가치의 정밀 단조품 생산을 위해 기술개발에 많은 노력을 기울이고 있는 회사이다. 본 논문 에서는 진합정공의 냉간단조 생산 기술을 예비처리 과정과 냉간단조법, 단조소재, 단조 금 형으로 나누어 개략적으로 소개함으로써 중소기업형인 국내 단조 기업의 생산 기술과 생산 현황을 파악하고자 하였다. 이러한 시도를 통하여 국내 단조 기술의 수준을 파악할 수 있을 것이며, 기술 개발을 위한 산학협동의 기반을 마련할 수 있을 것으로 기대된다.

• Transactions of the Korean Society of Mechanical Engineers
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• v.19 no.4
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• pp.896-907
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• 1995

Titanium 6242(.alpha. + .betha.) alloy has a good strength/weight ratio and is used for aircraft components such as engine disks and compressor blades. When this material is forged at an elevated temperature, the process parameters should be carefully controlled because the process window of this material is quite narrow. In the present investigation, a rigid-thermoviscoplastic finite element method is used to predict the deformation behavior and temperature/strain distributions in an engine disk during near-net shape hot forging. The purpose of the investigation is to obtain a proper ram speed profile, assuming the hydraulic press used in the forging is capable of varying ram speed during loading. In result, it was found that the ram speed at constant strain-rate of 0.5/sec shows a sound deformation behavior, a relatively uniform deformation and a good temperature distribution. This information is also valuable in predicting resulting microstructures in the disk.

• Transactions of Materials Processing
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• v.7 no.4
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• pp.347-353
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• 1998

A new approach of elastic finite element to die stress analysis in forging is presented in this paper. The die set analysis problem is formulated by considering contact problems under both mechanical and thermal loads. In the approach, amount of shrink fit is controlled by thermal load i.e., temperature difference between die insert and shrink fits. The loading conditions are extracted automatically from a forging simulator. The predicted solution is compared with analytical one and it has been shown that the predicted results are in excellent agreement with the analytical ones. An application example is given, which was found in a cold forging company.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.13 no.3
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• pp.56-62
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• 2014

During the hot forging process, the most common cause of tool failure is wear. Tool wear results in the gradual loss of part tolerances, after which eventually the tool must be replaced or repaired. In order to maximize the lifetimes of forging tools, it is important to investigate the wear mechanisms of these tools. In this study, the hot forging of the outer race of an automotive constant-velocity joint was analyzed by a finite element method to investigate the wear distribution, especially the amount and location of the maximum expected wear damage, using Archard's wear model, which was modified considering the forging temperature. Forging analyses were carried out after modifying blocker forging tools based on established versions. The modified blocker tools resulted in an increase in the tool life up to 31% with a finisher punch.

• Transactions of the Korean Society of Mechanical Engineers
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• v.13 no.1
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• pp.190-198
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• 1989

Some Developments in computer aided procedures for cold forging process and tool design of rotationally symmetric cup shape parts are described. The developed system enables appropriate forging sequence to be determined automatically, together with details of corresponding preform, die and punch design. The computer program developed is interactive and written in BASIC. This system not only assist the heavy work of designers but greatly shorten the time of design.

• Proceedings of the KAIS Fall Conference
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• 2009.05a
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• pp.525-527
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• 2009

본 논문에서는 자동차 공조부품인 리시버드라이어로서 플랜지와 바디로 구성되어 있다. 리시버드라이어는 냉매 중 포함된 습기 및 기타 불순물을 차단하는 부품으로서 사이트글라스가 부착되어 냉매의 흐름의 상태를 알 수 있다. 또한 압력 밸브가 부착되어 있어 냉매 회로의 압력과 온도가 상승하면 녹아서 냉매를 배출하므로 배관이나 부품들의 압력에 의해서 파괴되는 것을 방지 할 수 있다. 최근 경제적 성형에 관심이 많아 대표적 성형공정인 냉간단조를 적용하여 소재 회수율 및 절삭 비용 등을 절감하는데 목적을 두었다. 냉간단조를 적용하여 자동차 공조 부품인 플랜지와 바디를 개발하는데 공정설계, 금형설계, 금형제작 기술을 확보하였다.