Transactions of the Korean Society of Mechanical Engineers A (대한기계학회논문집A)

The Korean Society of Mechanical Engineers (대한기계학회)
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Investigation of Unbalanced Mass of a Work Roll in a Cold Rolling Mill

냉간 압연기에서 작업롤의 질량 불평형에 관한 연구

  • Kim, Young-Deuk (Dept. of Mechanical Engineering, Pohang University of Science and Technology (POSTECH)) ;
  • Kim, Chang-Wan (School of Mechanical Engineering, Konkuk Univ.) ;
  • Park, Hyun-Chul (Dept. of Mechanical Engineering, Pohang University of Science and Technology (POSTECH))
  • 김영득 (포항공과대학교 기계공학과) ;
  • 김창완 (건국대학교 기계설계학과) ;
  • 박현철 (포항공과대학교 기계공학과)
  • Received : 2011.10.18
  • Accepted : 2012.01.26
  • Published : 2012.04.01
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Abstract

An abrasion due to continuous friction between a work roll and strip causes the mass of the work roll to be unbalanced in the rolling process. We developed a mathematical model for the rolling mill considering the unbalanced mass and verified the model experimentally. The work roll was approximated as a rigid rotor with eccentricity, and the effect of the unbalanced mass on chatter vibration was investigated. The joint forces computed by quasistatic analysis were applied to the work roll in the rolling mill. Transient responses were obtained, and frequency analysis was performed by solving equations of motion using a direct integration method. Horizontal vibrations were more strongly affected by eccentricity than vertical vibrations. In the horizontal direction, a small eccentricity of 1% of the work roll radius considerably increased the amplitude of the chatter frequency.

압연공정 중에 작업롤은 스트립과의 지속적인 마찰에 의해 마모가 발생하여, 질량 불평형이 발생하게 된다. 이러한 작업롤의 질량 불평형을 고려한 압연기의 수학적 모델을 제안하였고, 이 모델은 실험에 의해 검증되었다. 작업롤은 편심을 가진 강체 로터로 가정되어, 질량 불평형의 채터 진동에 대한 영향을 분석하였다. 스핀들의 준평형 해석을 통해 계산된 조인트 힘은 압연기의 작업롤에 외력으로 작용시켰다. 압연기의 운동방정식을 직접적분법으로 풀어 과도 응답을 얻고 주파수 분석을 수행하였다. 편심은 수직 방향의 진동보다 수평 방향의 진동에 더 큰 영향을 끼쳤는데, 작업롤 반경의 1%의 편심거리도 수평 방향 채터 주파수의 진폭을 크게 상승시킬 수 있다는 것을 확인하였다.

Keywords

References

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