• Title/Summary/Keyword: Ball screw

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A Study on the Driving System Using Ball Screw (볼나사를 이용한 이송계에 관한 연구)

  • 이상조;남원우
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 1995.10a
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    • pp.981-984
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    • 1995
  • The feed system using ball screw is constructed by ball screw, support bering and LM guide, and servo system for driving ball screw. AC servo motr drives ball screw which was connected by coupling. In this study, a new axial direction dynamic modeling of ball screw driving system was developed, and forced vibraition test using the impact hammer was experimented. The simulation result is compared with experimental result, which defines the reliability of mathematical modeling.

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A Study on Control of the Thermal Expansion for Ball Screw of CNC Machin Tools (CNC 공작기계용 볼스크류의 열팽창 억제에 관한 연구)

  • 전언찬
    • Journal of the Korean Society of Manufacturing Technology Engineers
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    • v.7 no.4
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    • pp.73-78
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    • 1998
  • In this paper, we have studied about the thermal expansion of the ball screw used for the CNC machine tools. The hollow ball type is used for the ball screw. We have compared the conventional cooling system and function with the improved cooling system and function which is developed the path providing cooling oil in hollow ball screw. That is the temperature variation and positioning accuracy are analyzed of the ball screw. We have obtained the following results through this experiment. 1) The improved cooling system of the hollow ball screw for CNC machine tools was developed 2) The improved cooling system of the hollow ball screw has a large effectiveness on restraining the thermal expansion of the ball screw. 3) The positioning accuracy of the ball screw was improved about 2~4$\mu$m using temperature -controlled cooling oil.

A Study of Compensatio of Thermal Displacement of the Ball Screw in CNC Lathe (CNC 선반에서 BALL ACREW의 열변위 보정에 관한 연구)

  • 홍성오;김병철
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 1993.10a
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    • pp.181-186
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    • 1993
  • Thermal expansion of ball screw in the semi-closed loop type CNC LATHE introduces positioning errors directly along the travelling the axis. In this paper the thermal displacements of the ball screw were estimated by using macro variable. The estimated displacements of the ball screw were given to the ball screw of the CNC LATHE under the constant driving conditions were measured to examine the effectiveness of the compensation method. The results showed that thermal displacements of the ball screw could be maintained less then 6 .mu.m positioning accaracy while using this compensation.

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Precision Measurement System forBall Screw Pitch Error (볼스크류 전구간 피치오차 측정시스템)

  • 박희재;김인기
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 1993.10a
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    • pp.279-285
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    • 1993
  • This paper presents a precision automatic measuring system for ball screw Pitch. Ball screw is mounted on a precision indexing table, and the ball screw pitch is measured via magnetic scale, where the indexing and measurement are performed by a PC. For precision indexing of ball screw, direct driven motor is coupled to the designed dead and live centers; the performance of the centers are assessed with a precision master sylinder,such as radial motion,tilt motion, and axial motions. An error compensation model is constructed for the measurement system of ball screw pitch, where the error motions of indexing system as well as the scale measurement system are combined to give the measurement error for the ball screw. The developed system proposes an automated precision measurement system for manufacturers and users of ball screw.

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A Study on Improvement of Repeatability induced Thermal deformation of the ball screw (볼나사 열변형에 따른 반복정밀도 개선에 관한 연구)

  • 조규재
    • Proceedings of the Korean Society of Machine Tool Engineers Conference
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    • 1997.10a
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    • pp.31-36
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    • 1997
  • Thermal expansion of the ball screw in semi-closed loop type CNC Lathe directly affects the position precision along the travel axis. In this paper, the thermal displacement of the ball screw is estimated by using macro variables. The estimated displacements of the ball screw are managed by calculating the interval of pitch error rate in the NC. The thermal behaviour of the ball screw of the CNC Lathe, under the constant operating conditions, was measured to examine the effectiveness of this compensation method. The results showed that thermal displacement of the ball screw could be maintained its accuracy better than 6${\mu}{\textrm}{m}$ while applying this method.

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A Study on Improvement of Accuracy of Positioning Induced Thermal Deformation of the Ball Screw in CNC Lathe (CNC 선반에서 볼 나사 열변형에 따른 위치결정 정도 개선에 관한 연구)

  • 홍성오
    • Journal of the Korean Society of Manufacturing Technology Engineers
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    • v.8 no.1
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    • pp.45-51
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    • 1999
  • Thermal expansion of the ball screw can directly affect the accuracy of positioning along the travel axis in the semi-closed loop type CNC Lathe. In this paper, use of MACRO variables can make the thermal displacement of the ball screw estimated. Also, the estimated displacements of the ball screw are controlled by calculating the interval of pitch error rate in the Numerical Control(NC). Under the constant operating conditions, the thermal expansion of the ball screw was measured to confirm the effectiveness of the compensation method in the CNC Lathe. By using this method the results show that the thermal displacement of the ball screw could be reduced to 20% compared with ordinary method.

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A Study on Structure of Support Ball Screw and Arrangement of Combined Bearing (볼나사 지지 구조와 베어링 조합 배열에 관한 연구)

  • 홍성오;정성택;조규재
    • Transactions of the Korean Society of Machine Tool Engineers
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    • v.11 no.3
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    • pp.51-56
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    • 2002
  • In order to achieve high precision machine tools, Performance enhancement of feed drive systems is required. One of the important technical issues is how to decrease thermal expansion of ball screw in proportion to the increase of machining speed. When measuring force of stretch of ball screw, since not only actual expansion and the value of bending have to be considered, it is impossible to define the exact value of expansion. In addition, support bearings of ball screw gain considerable force in axial direction. It also generates thermal expansion on the ball screw, and deteriorates the performances of the hearings. In conclusion, it is impossible to give the pretension enough to absorb all the elongation due to thermal expansion generated during machine is running. If given bed column and saddle are all bent to chance machine accuracy, and the support bearings of ball screw is damaged.

Practical Ultraprecision Positioning of a Ball Screw Mechanism

  • Sato, Kaiji;Maeda, Guilherme Jorge
    • International Journal of Precision Engineering and Manufacturing
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    • v.9 no.2
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    • pp.44-49
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    • 2008
  • This paper describes the problem of ultraprecision positioning with a ball screw mechanism in the microdynamic range, along with its solution. We compared the characteristics of two ball screw mechanisms with different table masses. The experimental results showed that the vibration resulting from the low stiffness of the ball screw degraded the positioning performance in the microdynamic range for the heavyweight mechanism. The proposed nominal characteristic trajectory following (NCTF) controller was designed for ultra precision positioning of the ball screw mechanism. The basic NCTF control system achieved ultra precision positioning performance with the lightweight mechanism, but not with the heavyweight mechanism. A conditional notch filter was added to the NCTF controller to overcome this problem. Despite the differences in payload and friction, both mechanisms then showed similar positioning performance, demonstrating the high robustness and effectiveness of the improved NCTF controller with the conditional notch filter. The experimental results demonstrated that the improved NCTF control system with the conditional notch filter achieved ultra precision positioning with a positioning accuracy of better than 10 nm, independent of the reference step input height.

A Study on Effect of Various Cooling Methods in Motion of High-Precision Ball Screw (고속 고정밀 볼 스크류 구동에 따른 강제 냉각방식의 효과에 관한 연구)

  • Kim, Su-Sang;Xu, Zhe-Zhu;Kim, Hyun-Koo;Lyu, Sung-Ki
    • Journal of the Korean Society for Precision Engineering
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    • v.30 no.3
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    • pp.254-259
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    • 2013
  • Ball screw system is widely used as a precision mechanical linear actuator that translates rotational motion to linear motion for its high efficiency, great stiffness and long life. Recently, according to the requirements of high accuracy and stiffness, the pre-load on the ball screw which means of remove the backlash in the ball screw is usually used. Because of the preload which means the frictional resistance between the screw and nut, becomes a dominating heat source and it generates thermal deformation of ball screw which is the reason for low accuracy of the positioning decision. There are several methods to solve the problem that includes temperature control, thermal stable design and error compensation. In the past years, researchers focused on the error compensation technique for its ability to correct ball screw error effectively rather than the capabilities of careful machine design and manufacturing. Significant amounts of researches have been done to real-time error compensation. But in this paper, we developed a series of cooling methods to get thermal equilibrium in the ball screw system. So we find the optimum cooling type for improving positioning error which caused by thermal deformation in the ball screw system.

레이저를 이용한 볼나사 리드오차 측정에 관한 연구

  • 윤영식;박철우;이상조
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 1994.10a
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    • pp.254-259
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    • 1994
  • Recently, the precision ball screw becomes the essence of the high-precision industries and is playing a key role in the positioning devices. The standard and definition of pitch error in a precision ball screw is specified by KS, JIS or ISO. However, the method of measuring the pitch error is not concrete. In this study. laser measurement system(LMS) with a laser position transducer and a machine-tools is developed. In order to verify the stability of the LMS, several experiments with the standard ball screw is performed.

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