• Title, Summary, Keyword: vibration mill

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Experimental Study on the Chatter Vibration at the Early Stands in Hot Strip Finishing Mills (열간 마무리 압연기 전단 스탠드의 채터 진동에 관한 실험적 연구)

  • Choi, Jae-Chan;Lee, Sung-Jin;Lee, Jun-Shin;Jun, Hyeng-IL
    • Journal of the Korean Society for Precision Engineering
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    • v.13 no.2
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    • pp.48-61
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    • 1996
  • In the hot strip mill, not only the chatter vibration of finishing stands has a great influence on the surface quality of hot products, but also that is the major factors to shorten the life of rolling mill housings or to create the machine troubles. As long as the mill has been operating, the low frequency chatter at the early mill stands (No.2 and No.3) of POSCO's Kwangyang No.2 hot strip mill had been detected when rolling certain types of products, e.g., thinner gage, hard grade products. For several years, the experimental study was undertaken to analyze the cause of the chatter vibration and establish the methods to avoid the vibration to acceptable levels. The analysis and solution to the vibration problem with recommendations and revised maintenance practice are the subjects of this article.

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The Cause of Vibration at Finishing Stands in a Hot Strip Mill (열간 사상압연기에서의 진동 원인)

  • 손붕호;노용래;이영호
    • Journal of KSNVE
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    • v.4 no.1
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    • pp.43-50
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    • 1994
  • Chatter vibration of a rolling machine in steel plants has a significant effect on thickness quality of the products. The cause and mechanism of the mill chattering is addressed through measurement of vibration and dynamic torque. An FFT system and an FM telemetry system are employed to collect data at several locations of possible damages. The results reveal the followings as sources of the mill vibration. The first is defects in roller bearings of a work roll chock. The second is instability of an oil film bearing in a backup roll chock, which has been investigated with a theoretical model describing the phenomenon. Dynamic torque is not the direct cause of mill vibration but rather influenced by the vibration. Appropriate treatment methods are suggested to address each of the above sources.

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Characteristic Analysis of Vibration in Finishing Mill (열연 사상압연기 진동 특성 분석에 관한 연구)

  • Shin, N.H.;Son, B.H.
    • Proceedings of the KSME Conference
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    • pp.578-583
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    • 2001
  • Chattering phenomenon is an abrupt relative vibration between the strip and rolls of rolling machine in working. It inevitably results from the progress of the degeneration in the mill facilities. This research was carried out in order to analyze the characteristic and find the cause of chatter mark in finishing mill and it was founded that major causes are facility character of driving part and special condition in case of excessive roll force.

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Chaotic Behaviour of Vibration signal for Rolling Mill Bearing Diagnistics (압연기 베어링진단을 위한 진동 신호의 카오스적 거동)

  • 배영철;김이곤;최남섭;김경민;정양희;최홍준;김서영;유권종
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.4 no.4
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    • pp.759-765
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    • 2000
  • A diagnosis system that provides early warnings regarding machine malfunction is very important for rolling mill so as to avoid great losses resulting from unexpected shutdown of the production line. But it is very difficult to provide early warnings in rolling mill. Because dynamics of rolling mill is non-linear. This paper shows a chaotic behavior of vibration signal in rolling mill using embedding method. Not only phase plane and Poincare map are implemented but also FH and histogram of vibration signal in rolling mill is presented by embedding method.

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Chaotic Behaviour of Vibration signal in Rolling Mill Bearing (압연기 베어링 진동 신호의 카오스적 거동)

  • 배영철;김이곤;최남섭;김경민;정양희;최홍준;김서영
    • Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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    • pp.634-637
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    • 2000
  • A diagnosis system that provides early warnings regarding machine malfunction is very important for rolling mill so as to avoid great losses resulting from unexpected shutdown of the production line. But it is very difficult to provide early warnings in rolling mill. Because dynamics of rolling mill is non-linear. This paper shows a chaotic behaviour of vibration signal in rolling mill using embedding method. Not only phase plane and Poincare map are implemented but also FFT and histogram of vibration signal in rolling mill is presented by embedding method.

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Chaotic Phenomenon of Vibration signal in Rolling Mill Soaring (회전 기기에서의 카오스 현상에 관한 연구)

  • 배영철;김주완
    • Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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    • pp.374-377
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    • 2001
  • A diagnosis system that provides early warnings regarding machine malfunction is very important for rolling mill so as to avoid great losses resulting from unexpected shutdown of the production line. But it is very difficult to provide early warnings in rolling mill. Because dynamics of rolling mill is non-linear. This paper shows a chaotic behaviour of vibration signal in rolling mill using embedding method. Not only phase plane and Poincare map are implemented but also FFT and histogram of vibration signal in rolling mill is presented by embedding method.

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Hepatoprotective Effects of Amorphous and Nnno-Particle Pyeparations of Ursodeoxycholic Acid in CC4-Induced Mice : Effects of Three Types of Fine Grinding Mills (Ursodeoxycholic acid의 무정형 초미립자제제들의 CC4 유도 간손상 생쥐에 대한 보호 효과)

  • 정한영;곽신성;김현일;최우식;이지현;김애라;박태현;정해영;김유정
    • Biomolecules & Therapeutics
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    • v.10 no.1
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    • pp.1-6
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    • 2002
  • The particle size of medicinal materials is an Important physical property that affects the phar-maceutical behaviors such as dissolution, chemical stability, and bioavailability of solid dosage forms. The size reduction of raw medicinal powder is needed to formulate insoluble drugs or slightly soluble medicines and to improve the pharmaceutical properties such as the solubility, the pharmaceutical mixing, and the dispersion. The objective of the present study is to evaluate physiological activity of amorphous and nano-particle prep-arations of insoluble drug, ursodeoxycholic acid (UDCA), which were made by three types of fine grinding mills. The change of physical properties of ground UDCA was conformed by Mastersiger microplus and X-ray diffraction. We have investigated hepatoprotective effects of the nano-particle preparations of UDCA by plan-etary mill, vibration rod mill and jet mill in $CCI_4$-induced oxidatively injured mouse liver. The results showed that nano-particle preparations of UDCA all decreased reactive oxygen sepecies generation and lipid peroxi-dation in $CCI_4$-induced oxidative stress mice. Among them, nano-particle preparations by vibration rod mill and jet mill showed more significantly hepatoprotective effects compared to intact UDCA and planetary mill-ground UDCA. These results suggest that ground UDCA with vibration rod mill and jet mill shows a high amorphous state and the improved dissolution.

Characteristic Analysis of Chattering in Finishing Mill (열연 사상압연기 채터링 특성 분석에 관한 연구)

  • Shin, N.H.;Lim, E.S.
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • pp.1854-1858
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    • 2000
  • Chattering phenomenon is an abrupt relative vibration between the strip and rolls of rolling machine in working. It inevitably results from the progress of the degeneration in the mill facilities. This research was carried out in order to analyze the characteristic and find the cause of chatter mark in finishing mill and it was founded that one of major cause is appearance of dead zone at pinion stand in case of excessive roll force.

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The Effect of Gear Contact Stiffnesses on the Vibration of Torsional Geared Systems for a Mill Turret (복합공구대 비틀림계 진동에 대한 기어 맞물림 강성의 영향에 관한 연구)

  • Kim, Chae-sil;Kim, Soo-Tae;Cho, Soo-Yong;Jung, Hoon-Hyung
    • Journal of the Korean Society of Manufacturing Process Engineers
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    • v.8 no.2
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    • pp.32-39
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    • 2009
  • This paper describes mathematical models of the torsional geared driving system for the indexing path and the mill driving path in a mill turret. The eigenvalue analysis for the models is conducted both with and without the gear contact stiffnesses. The natural frequency leads to the effect of gear contact stiffnesses on the vibration of torsional geared systems in a mill turret. It is necessary to analyze eigenvalues of the complex geared torsional system in order to prevent the unexpected vibrations.

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Framework Development for Fault Prediction in Hot Rolling Mill System (열간 압연 설비의 고장 예지를 위한 프레임워크 구축)

  • Son, J.D.;Yang, B.S.;Park, S.H.
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.21 no.3
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    • pp.199-205
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    • 2011
  • This paper proposes a framework to predict the mechanical fault of hot rolling mill system (HRMS). The optimum process of HRMS is usually identified by the rotating velocity of working roll. Therefore, observing the velocity of working roll is relevant to early know the HRMS condition. In this paper, we propose the framework which consists of two methods namely spectrum matrix which related to case-based fast Fourier transform(FFT) analysis, and three dimensional condition monitoring based on novel visualization. Validation of the proposed method has been conducted using vibration data acquired from HRMS by accelerometer sensors. The acquired data was also tested by developed software referred as hot rolling mill facility analysis module. The result is plausible and promising, and the developed software will be enhanced to be capable in prediction of remaining useful life of HRMS.