• 제목/요약/키워드: Machine tools accuracy

검색결과 302건 처리시간 0.026초

Grid Encoder를 이용한 NC공작기계 동적정밀도 측정에 관한 연구 (A Study on Measurement of Dynamic Accuracy Using Grid Encoder in NC Machine Tools)

  • 이찬호;이방희;김성청
    • 한국정밀공학회:학술대회논문집
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    • 한국정밀공학회 2003년도 춘계학술대회 논문집
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    • pp.378-381
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    • 2003
  • Efficient development of method on a performance evaluation for machine tools has been regarded as the most important work for accuracy and quality enhancement to every user and manufacturer. A evaluation method of accuracy for machine tools has been studied recently according to the rapid increase of interest in precision machine tools. To this point of view, the circular interpolation test of machine tools is recognized as the most useful method to distinguish a dynamic accuracy of NC machine tools by ISO and ANSI/ASME, etc. In this paper, we have studied and developed the form measurement system with grid encoder to analyse the final accuracy of NC machine tools. we have analyzed the servo system error and geometric error of NC machine tools through measuring a dynamic error signal by this system. and then we verified the experimental result and enhanced the reliability by means of comparing the characteristics of the developed system with the kinematic ball-bar system.

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2차원 프로브에 의한 NC공작기계의 운동 정밀도 측정 -제2보 직선운동 정밀도 측정- (Measurement of Motion Accuracy by Two-dimensional Probe on NC Machine Tools -2nd Report, Measurement of the Linear Motion Accuracy-)

  • 전언찬;소산전중덕;제정신;각전윤일랑
    • 한국정밀공학회지
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    • 제14권7호
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    • pp.15-21
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    • 1997
  • This paper presented a linear motion accuracy by using two-dimensional probe with the master block and the square for NC machine tools. This measuring system could be measured motion error due to numerical control system. The results of measurement and simulation for motion error were similar, and so, this system had enough accuracy to measure a linear motion accuracy for NC machine tools. The experimental results are as follows. 1. This measuring system could be measured motion error due to mumerical control system. 2. The results of measurement and simulation for motion error were similar. 3. This measuring system had enough accuracy to measure a linear motion accuracy for NC machine tools.

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발파진동으로 인한 공작기계 가공정도의 영향 평가 (Evaluation of the Influence of Blast Vibration on Machine Tool Accuracy)

  • 이진갑
    • 한국산학기술학회논문지
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    • 제15권8호
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    • pp.4790-4795
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    • 2014
  • 공작기계는 기계산업의 생산 및 시제품가공 등에 널리 적용되고 있다. 폭발시 발생하는 지반진동은 인근 구조물의 손상이나 시설에 많은 영향을 미친다. 본 논문은 발파진동이 공작기계의 가공정밀도에 미치는 영향을 고찰하였다. 발파진동과 발파시 공작기계의 진동을 측정하였고, 진동허용치를 기준으로 평가하였다. 공작기계의 진동허용치를 기준으로 할 경우 본 연구에 사용된 공작기계의 발파시 진동허용치는 SLIGHTLY ROUGH~ROUGH에 해당된다. 발파진동이 반복될 경우 정밀도가 저하될 가능성이 많다.

Measurement of the Volumetric Thermal Errors for CNC Machining Center Using the Star-type-styluses Tough Probe

  • Lee, Jae-Jong;Yang, Min-Yang
    • International Journal of Precision Engineering and Manufacturing
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    • 제1권1호
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    • pp.111-117
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    • 2000
  • One of the major limitations of productivity and quality in metal cutting is the machining accuracy of machine tools. The machining accuracy is affected by geometric errors, thermally-induced errors, and the deterioration of the machine tools. Geometric and thermal errors of machine tools should be measured and compensated to manufacture high quality products. In metal cutting, the machining accuracy is more affected by thermal errors than by geometric errors. This paper models the thermal errors for error analysis and develops an on-the-machine measurement system by which the volumetric errors are measured and compensated. The thermal error is modeled by means of angularity errors of a column and thermal drift error of the spindle unit which are measured by the touch probe unit with a star type styluses and a designed spherical ball artifact (SBA). Experiments show that the developed system provides a high measuring accuracy, with repeatability of $\pm$2$\mu\textrm{m}$ in X, Y and Z directions. It is believed that the developed measurement system can be also applied to the machine tools with CNC controller. In addition, machining accuracy and product quality can be also improved by using the developed measurement system when the spherical ball artifact is mounted on a modular fixture.

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기상계측 시스템을 이용한 머시닝센터의 열변형 오차 모델링 및 오차측정 (Modeling and Measurement of Thermal Errors for Machining Center using On-Machine Measurement System)

  • 이재종;양민양
    • 한국정밀공학회지
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    • 제17권1호
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    • pp.120-128
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    • 2000
  • One of the major limitations of productivity and quality in metal cutting is the machining accuracy of machine tools. The machining accuracy is affected by geometric errors, thermally-induced errors, and the deterioration of the machine tools. Geometric and thermal errors of machine tools should be measured and compensated to manufacture high quality products. In metal cutting, the machining accuracy is more affected by thermal errors than by geometric errors. This paper models of the thermal errors for error analysis and develops on-the-machine measurement system by which the volumetric error are measured and compensated. The thermal error is modeled by means of angularity errors of a column and thermal drift error of the spindle unit which are measured by the touch probe unit with a star type styluses and a designed spherical ball artifact (SBA). Experiments, performed with the developed measurement system, show that the system provides a high measuring accuracy, with repeatability of $\pm$2${\mu}{\textrm}{m}$ in X, Y and Z directions. It is believed that the developed measurement system can be also applied to the machine tools with CNC controller. In addition, machining accuracy and product quality can be improved by using the developed measurement system when the spherical ball artifact is mounted on the modular fixture.

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CNC 공작기계의 위치결정 정밀도 향상에 관한 연구 (An Improvement of Positioning Accuracy for CNC Machine Tools)

  • 전언찬;광전강굉;제정신;남궁척
    • 한국정밀공학회지
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    • 제11권6호
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    • pp.5-11
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    • 1994
  • We have investigated the variation of dwell and warm-up time for effects of positioning accuracy of the CNC machine tools with an laser measuring system. Also, we strdied the effect of improvement of the positioning accuracy by variation of the temperature for hollow ball screw, which mostly used as drive mechanism of CNC machine tools. We dbtained the effectiveness of cooling effect of the new cooling system, compared with the conventional cooling system.

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Machining Center의 공간정도 측정장치의 개발 (Developement of Measuring Units of Space Motion Accuracy in Machining Center)

  • 김영석;남궁석
    • 한국정밀공학회지
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    • 제12권2호
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    • pp.37-47
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    • 1995
  • In recent years, it has been variously developed for testing the accuracy of circular motion of NC machine tools, for example Telescoping Ball Bar Method by Bryan, Circular test Method by Knapp and $r^{-{\theta} }$ Method by Tsutsumi etc., but these methods are all 2-dimentional measuring methods on plane. These simple methods of circular motion accuracy test of NC machine tools have been studied by many reserchers as above, but it is not yet settled in the code of measuring methods of motion errors of NC machine tools, because of errors of measuring units and sensors, and also especially the difficulties of centering of measuring units and the spindle of machining center. In this paper, in use of 2 rotary encoders and 1 magnetic type linear scale with resolution of 0.5 .mu. m, it has become possible for measuring of 3 dimentional space motion accuracy.

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CNC공작기계의 열변형 오차보정 (II) - 알고리즘 및 시스템 인터폐이스 중심 - (Algorithm of Thermal Error Compensation for the Line Center - System Interface -)

  • 이재종;최대봉;박현구;류길상
    • 한국공작기계학회:학술대회논문집
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    • 한국공작기계학회 2002년도 추계학술대회 논문집
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    • pp.417-422
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    • 2002
  • One of the major limitations of productivity and quality in metal cutting is the machining accuracy of machine tools. The machining accuracy is affected by geometric errors, thermally-induced errors, and the deterioration of the machine tools. Geometric and thermal errors of machine tools should be measured and compensated to manufacture high quality products. In metal cutting, the machining accuracy is more affected by thermal errors than by geometric errors. In this study, the compensation device and temperature-based algorithm have been implemented on the machining center in order to compensate thermal error of machine tools under the real-time. The thermal errors are predicted using the neural network and multi-regression modeling methods. In order to compensate thermal characteristics under several operating conditions, experiments performed with five gap sensors and manufactured compensation device on the horizontal machining center.

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NC 밀링머신의 Volumetric 오차보상을 통한 포물면 가공의 정밀도 향상 (Enhancement of a parabolic face working accuracy using volumetric error compensation of NC milling machine)

  • 이찬호;정을섭;이응석;김성청
    • 한국정밀공학회:학술대회논문집
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    • 한국정밀공학회 2000년도 춘계학술대회 논문집
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    • pp.917-921
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    • 2000
  • One of the major limitations of productivity and quality in machining is machining accuracy of the machine tools. The machining accuracy is affected by geometric, volumetric errors of the machine tools. This paper suggests the enhancement method of machining accuracy for precision machining of high quality metal reflection mirror or optics lens, etc. In this paper, we study 1) the compensation of linear pitch error with NC controller compensation function using laser interferometer measurement, 2) the method for enhancing the accuracy of NC milling machining by modeling and compensation of volumetric error, 3) the generation of the parabolic face profile. And the method is verified by the parabolic face machining experiment with a vertical three axes NC milling machine. After this study, we will inspect using On-machine measurement and study the repetitive machining by a compensated path

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공작기계 열변형의 실험적 보정에 관한 연구 (A Study on the Experimental Compensation of Thermal Deformation in Machine Tools)

  • 윤인준;류한선;고태조;김희술
    • 한국공작기계학회논문집
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    • 제13권3호
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    • pp.16-23
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    • 2004
  • Thermally induced errors of machine tools have been recognized as one of the most important issues in precision machining. This is probably the most formidable obstacle to obtain high level of machining accuracy. To this regard, the experimental compensation methodologies such as software-based method or origin shift of machine tool axes have been suggested. In this research, to cope with thermal deformation, a model based correction was carried out with the function of an external machine coordinate shift. Models with multi-linear regression or neural network were investigated to selected a good one for thermal compensation. Consequently, multi-linear regression model combined with origin shift was verified good enough form the machining of dot matrices of plate with ball end milling.