• Title/Summary/Keyword: Grinding wheel spindle

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Dynamic Chanrateristics of Spindle for the External Cylindrical Grinding Machine Considered the Shell Mode Vibration of Wheel (Wheel의 원반 진동을 고려한 외경연삭 주축의 동특성)

  • 하재훈;이선규
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 1995.10a
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    • pp.1000-1004
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    • 1995
  • In the case of the external cylindrical grinding machine, the grinding mechanism can cause a wheel to vibrate due to a wheel cutter. This phenomena will bring about the unsymmetric wear up to high frequency without any relation of rotational speed. So far, when the grinding spindle is analyzed, it is assumed that a wheel is considered as lumped mass at the endof a beam. Nowadays, there is a tendency to use the wheel with a lsrge diameter or CBN wheel to achieve the high speed and accuracy grinding performance. Therefore, this kind of assumption is no longer valid. At the analysis of the grinding spindle, the parameter which dapends on the dynamic characteristics is a combination force between each part. For example, there is the tightness torque of a bolt and taper element in the grindle. In addition, the material property of the wheel can contribute the dynamic characteristics. This paper shows the mode participation of the shell mode of the wheel in the grindle and the dynamic characteristics according to the parameters which are the configuration of the flange and tightness torque of a bolt and taper. Modal parameter of the wheel, flange and the spindle can be extracted through frequency response function obtained by modal test. After that, by changing the tightness torque and kinds of wheel, we could accomplish the test in the whole combined grinding spindle. To perform modal analysis of vibration characteristics in the grinding spindle, we could develop the model of finite element method.

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Effects of Flange Joint on the Dynamic Characteristics of the External Cylindrical Grinding Wheel Spindle (외경연삭 휠 주축의 진동특성에 미치는 플랜지 결합부의 영향)

  • Kim, Sun-Min;Ha, Jae-Hoon;Lee, Sun-Kyu
    • Journal of the Korean Society for Precision Engineering
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    • v.16 no.10
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    • pp.118-125
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    • 1999
  • In the grinding process, generally, the exciting forces with high frequency can be generated due to the wheel wear and the grinding process. As the grinding speed increases, the precise investigation about the wheel dynamic characteristics is required. Conventionally the wheel-spindle has been considered with lumped model in dynamic modeling. With this lumped model, the significant mode resulted from the shell mode of wheel can be readily ignored. This paper suggests the new analysis model which includes the shell mode of wheel in modeling the wheel-spindle assembly. Furthermore, based on the suggested model, the effects of the bolt tightening force and the taper tightening force on the dynamic properties are investigated by the finite element modal analysis and the experimental method. As a result of investigation, the shell mode vibration of wheel affects the dynamic characteristics of the spindle assembly. Also, the vibration modes of the spindle assembly are significantly affected by the joint tightening forces.

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The development of Centerless Grinder for Ferrule Grinding (페룰 가공용 초정밀 센터리스 연삭기 개발)

  • CHO S.J.;EBIHARA EBIHARA;TSUKISHIMA TSUKISHIMA;YOON J.S.;CHO C.R.
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 2005.06a
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    • pp.6-9
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    • 2005
  • In this study, the ultra precision centerless grinder for ferrule grinding was designed. As the good-qualified ferrule is required a precise and fine grinding, grinding machine for ferrule must have a high accuracy and a sufficient stiffness. The centerless grinder is composed of the high damping concrete bed, grinding wheel spindle unit, regulating wheel spindle unit, feeding table and dressing unit. For a newly developed centerless grinder, hydrostatic system with high precision feeding and high stiffness was proposed. The grinding and regulating wheel spindle units were composed of hydrostatic spindle and feeding table was hydrostatic table. The prototype of hydrostatic table was manufactured and tested.

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A Study on the Machining characteristics in the Cylindrical Plunge Grinding using Spindle Motor Current Signal (주축모터전류신호를 이용한 원통 연삭시 가공 특성에 관한 연구)

  • 김남훈
    • Proceedings of the Korean Society of Machine Tool Engineers Conference
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    • 1999.10a
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    • pp.507-512
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    • 1999
  • In modern engineering practice, the grinding process is one of the most important and widely used operations for the precision finishing of components. In this paper, machining characteristics of external plunge grinding were investigated by using spindle motor current signal through hall sensor. Grinding experiments were performed in terms of various grinding conditions such as wheel speed, workpiece speed, infeed rate and spark-out time with conventional vitrified bonded WA wheel. The relationship between spindle motor current signal and metal removal rate in terms of infeed rate was induced the by analyzing spindle motor current signal.

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Design of a Centerless Grinder for Ferrule Grinding (페룰 가공용 Centerless Grinder 설계)

  • Cho, Soon-Joo;Kim, Hyung-Gil;Cho, Chang-Rae
    • Proceedings of the KSME Conference
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    • 2004.04a
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    • pp.1087-1091
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    • 2004
  • In this study, the ultra precision centerless grinder for ferrule grinding was designed. The centerless grinder is composed of the high damping concrete bed, grinding wheel spindle unit, regulating wheel spindle unit, feeding table and dressing unit. For a newly developed centerless grinder, hydrostatic system with high precision feeding and high stiffness was proposed. The grinding and regulating wheel spindle units were composed of hydrostatic spindle and feeding table was hydrostatic table. The prototype of hydrostatic table was manufactured and tested.

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A Study on the Diamond Wheel Wear in Ceramic Grinding (세라믹 연삭에서 다이아몬드 숫돌 마멸에 관한 연구)

  • 공재향;유봉환;소의열;이근상;유은이
    • Proceedings of the Korean Society of Machine Tool Engineers Conference
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    • 2001.10a
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    • pp.344-348
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    • 2001
  • In this study, experiments were carried out to investigate the characteristics of grinding and wear process of diamond wheel grinding ceramic materials. Normal component of grinding resistance was decreasing while increase of spindle speed. The resistance of vitrified bond wheel was less then that of resinoid bond wheel because of imbedded large holes on the surface of cutting edge. Surface roughness was decreasing while increase of spindle speed. The surface roughness after using vitrified bond wheel was less than that of resinoid bond wheel because of small elastic deformation. After continuous grinding of ceramics, cutting edge ratio of resinoid bond wheel decreases. For the case of vitrified bond wheel, cutting edge ratio does not change.

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A Study on the Evaluation of Machining States in the Cylindrical Plunge Grinding using the Current Signals of a Spindle Motor (주축모터전류신호를 이용한 원통 연삭시 가공 상태 평가에 관한 연구)

  • 송지복;이은상;김남훈
    • Journal of the Korean Society for Precision Engineering
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    • v.17 no.6
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    • pp.76-82
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    • 2000
  • This paper describes the machining characteristics of cylindrical plunge grinding. The study investigates the process using the current signals of a spindle motor through a hall sensor. Grinding experiments were conducted under various conditions such as wheel speeds, workpiece speeds and infeed rates with a conventional vitrified bonded wheel. Analyzing the current signal of the spindle motor, a relationship between current signals and the metal removal rate in terms of the in(red rate is induced. It was also shown that a hall sensor has similar capabilities in evaluation of grinding behavior compared to the AE signals, which are useful far monitoring the grinding process.

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Wear Characteristics of Diamond Wheel according to bond in Ceramic Grinding (세라믹 연삭에서 결합제에 따른 다이아몬드 휠의 마멸 특성)

  • 공재향;유봉환;소의열;이근상;유은이;임홍섭
    • Transactions of the Korean Society of Machine Tool Engineers
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    • v.11 no.4
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    • pp.75-81
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    • 2002
  • In this study, experiments were carried out to investigate the characteristics of grinding and wear process of diamond wheel during grinding ceramic materials. Normal component of grinding resistance was decreasing while increase of spindle speed. The resistance of vitrified bond wheel was less then that of resinoid bond wheel because of imbedded large holes on the surface of cutting edge. Surface roughness was decreasing while increase of spindle speed. The surface roughness using vitrified bond wheel was less than that of resinoid bond wheel because of small elastic deformation. After continuous finding of ceramics, cutting edge ratio of resinoid bond wheel decreased. For the case of vitrified bond wheel, cutting edge ratio did not change.

Development of ELID Monitoring System and its Application to ELID Grinding of Structural Ceramics (ELID 연삭 모니터링 시스템의 개발과 구조 세라믹스 적용 사례)

  • Kwak, Tae-Soo;Kim, Gyung-Nyun;Kwak, Ihn-Sil
    • Journal of the Korean Society for Precision Engineering
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    • v.30 no.12
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    • pp.1245-1251
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    • 2013
  • This study has focused on development of ELID monitoring system and its application to ELID grinding of structural ceramics. ELID monitoring system was consisted of grinding equipment, ELID power supply, grinding wheel, electrode and monitoring program. It can give a real time data to check spindle grinding resistance, wheel revolution, dressing current and voltage in ELID grinding process. The performance of developed system was evaluated by applying to grinding of structural ceramics, silicon carbide and alumina. As the results of experiments, monitored data for spindle resistance and ELID dressing current was useful to check steady-state ELID grinding process. From the comparison of spindle resistance between ELID grinding and conventional grinding process according to change of depth of cut, it could be confirmed that the spindle resistance in ELID grinding was lower than conventional grinding process.

Analysis on the hydrostatic bearing using self-controlled restrictor or grinding wheel spindle (고정밀 연삭기 주축용 가변 면적 자기 보상형 리스트릭터 유정압 베어링 해석)

  • 조성만;박상신;안유민
    • Transactions of the Korean Society of Machine Tool Engineers
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    • v.10 no.1
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    • pp.23-29
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    • 2001
  • Cylindrical type of self-controlled restrictor are designed for hydrostatic bearing of grinding wheel spindle. Typical hydrostatic journal bearing with the designed restrictor is analytically model. According to the model, the affect of oper-ation parameters, such as, initial cross distance, supply pressure, diameter of two supply holes, pre-load of spring, and clearance between spindle and housing, on bearing stiffness are analyzed. From the results of the analysis, the optimum conditions of operation parameters that maximize the bearing stiffness are estimated.

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