• Title/Summary/Keyword: Counterblow Hammer

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Comparative Analysis of Mechanical Vibrations of an Air-Drop Hammer and a Counterblow Hammer in Forging Process (에어-드롭 해머와 카운터블로 해머 프레스 단조공정의 기계진동 비교해석)

  • Kim, S.T.;Choi, Y.H.;Ju, G.J.
    • Journal of Drive and Control
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    • v.19 no.4
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    • pp.10-18
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    • 2022
  • Air-drop hammer press and counterblow hammer press are widely used power-drop forging hammersemploying different forging blow mechanisms. It is important and necessary to analyze mechanical vibrations of these two different hammers in their forging processes in order to develop high performance forging hammers. In this study, these two forging hammers were mathematically modelled as mass-spring-damper systems. For these two different types of forging hammers, the forging efficiency and mechanical vibrations due to hammer forging blow were theoretically analyzed and compared. The force transmitted to the ground was also determined and compared. Especially, effects of mass ratio and restitution coefficient on forging efficiency were investigated.

Mechanical Vibration Characteristics Analysis of a Counterblow Hammer Press in the Forging Process (카운터블로 해머 프레스 단조공정의 기계진동 특성 해석)

  • Kim, Soo Tae;Ju, Gyeong Jin;Park, Geon Jong;Choi, Young Hyu
    • Journal of the Korean Society of Manufacturing Process Engineers
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    • v.21 no.8
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    • pp.43-52
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    • 2022
  • The vibration characteristics of a hammer press are important parameters for machine design and production control. In this study, a counterblow hammer press was mathematically modelled as a mass-spring-damper system in order to analyze its vibration characteristics. The forging efficiency was theoretically derived as a function of the mass ratio, momentum ratio, and the coefficient of restitution And the effects of the mass ratio, momentum ratio and the restitution coefficient on the forging efficiency were also investigated for two particular cases of the unit mass ratio and unit momentum ratio. Additionally, the vibration responses of the counterblow hammer press due to the ram colliding impact were analyzed, and the force transmitted to the foundation through the mounting unit was determined.

Determination of Number of Blows in Hammer Forging by Finite Element Method (유한요소법을 이용한 해머단조 공정에서 타격 횟수의 결정)

  • Jang, S.M.;Kim, S.H.;Lee, M.C.;Cho, B.J.;Joun, M.S.
    • Proceedings of the Korean Society for Technology of Plasticity Conference
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    • 2009.10a
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    • pp.338-341
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    • 2009
  • In this paper, three-dimensional finite element approach to determining the number of blows in hammer forging is presented. Energy efficiency which is a major factor affecting the number of blows in hammer forging is assumed to decrease linearly as die-material contact area increases. The approach is applied to predicting the number of blows in counterblow hammer forging of large crank shaft for medium sized ship engine.

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Determination of Blow Efficiency of the Forging Hammer (단조해머의 타격효율 결정)

  • 이성호;조남춘;이종수
    • Transactions of the Korean Society of Mechanical Engineers
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    • v.19 no.6
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    • pp.1539-1544
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    • 1995
  • Copper blow test to measure the forging capability of 35 ton counterblow hammer and upset of plasticine on the model hammer to investigate the change of the blow efficiency during the forging process have been performed together with finite element analyses of these experiments. The blow efficiency of the hammer has been found to be dependent on the friction and on the contact area between the die and the workpiece. The effects of the volume and the aspect ratio of the billet have not been found. Inferring from the experimental results and Schey's empirical formula on the forging load, we expect that the efficiency also varies with the flow stress of the workpiece material and with the shape complexity of the forging product.