• Title/Summary/Keyword: Roundness error

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An Analysis of Performance Error of Roundness Measuring Instrument -by phase different method- (眞圓度 測定器의 誤差特性에 대한 解析 -위상차법-)

  • 한응교;허문석;박익근
    • Journal of the korean Society of Automotive Engineers
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    • v.10 no.3
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    • pp.31-37
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    • 1988
  • A phase different method to evaluate the instrument error of roundness measuring instrument and the form error of specimens for the calibration of the instrument is used. An instrument with a rotary table supported by an air bearing was calibrated by using the standard balls as a standard. The calibration was carried out repeatedly by setting the same ball in 12 phase angles(per 30.deg.) on the table and by recording their roundness errors with a magnification of 100,000 times. As a result of data analysis of all the observations, readout at each of 144 orientations(per 2.5.deg.) from recorded data file, the error of performance of the instrument and the specimens are separated. In the particular instrument used in the present experiment, the error of the instrument was determined with the accuracy of 0.0164 (.mu.m) and the form error of the specimens was determined with the accuracy of 0.0264,0.0172(.mu.m), respectively. If the instrument was calibrated by using the above specimens, then the accuracy of the measurement of roundness error can be improved to about 0.017 (.mu.m).

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Effect of Roundness Error of a Crank Pin Bearing for a Marine Engine on the Minimum Film Thickness (박용엔진 크랭크 핀 베어링의 형상오차가 최소유막두께에 미치는 영향)

  • Ha, Yang-Hyup;Shin, In-Dong;Lee, Sang-Min;Lee, Seung-Jun;Lee, Deug-Woo
    • Tribology and Lubricants
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    • v.27 no.5
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    • pp.256-263
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    • 2011
  • Bearings of marine engines are operated under severe conditions because of dynamic load and low sliding speed. This paper deals with lubrication analysis of a crank pin bearing for a marine diesel engine. Journal center locus and oil film thickness are compared of crank pin bearing. In the past researches, journal bearings have been studied only about the surface of bearing. In addition to this conventional research, this paper analyzes the effect of roundness error of a journal and a bearing on the minimum film thickness. Numerical analysis has been studied by using Reynolds equation and also Half-Sommerfeld condition is applied as boundary condition. Futhermore, this study investigates the effect of roundness error change on the minimum film thickness. The results demonstrate that the bigger amplitude of roundness error yields, the lower minimum oil film thickness is. In comparison to previous research considered a journal and a bearing individually, the results considering a journal and a bearing together show that amplitude of roundness error of journal has very little effect on the minimum oil film thickness.

A Roundness Evaluation of Al-6061 Turning by Orthogonal Table and Multiple Linear Regression (직교배열에 의한 선삭과 회귀분석방법에 의한 Al-6061의 진원도 평가)

  • Jang, Sung-Min;Back, Si-Young
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.13 no.1
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    • pp.45-50
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    • 2012
  • This paper on analysis of roundness error after boring turning of Al-6061 materials with CNC lathe. Experiment applying turning parameters is based on experimental design method. A design and analysis of experiments is conducted to study the effects of these parameters on the roundness error using the S/N ratio and analysis of ANOVA. Multiple linear regression analysis is applied to compare experimental with predicted data in consideration of roundness error. To fixation pressure and the opening which are a turning parameter, the cutting depth and feed speed respected the objective attainment of dissertation and to be applied the result they investigated.

The Roundness Prediction at Numerical Control Machine Using Neural Network (수치제어 공작기계에서 신경망을 이용한 진원도 예측)

  • Shin, Kwan-Soo
    • Journal of the Korean Society of Manufacturing Technology Engineers
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    • v.18 no.3
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    • pp.315-320
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    • 2009
  • The purpose of this study is to predict the roundness of Numerical Control Machining so that helps the operator to choose the right machining conditions to produce a product within the given error limits. Learning of neural network is Backpropagation theory. From this study, the base was set to setup the database to produce precisely machined product by predicting the rate of error in the fabrication facility which does not have the environment to analyze it.

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An Analysis of Performance Error of High Precision Measuring Instrument (진원도 측정기의 오차특성에 관한 연구)

  • 한응교;노병옥;허민석
    • Transactions of the Korean Society of Mechanical Engineers
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    • v.13 no.5
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    • pp.862-874
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    • 1989
  • A phase evil method and spectrum analysis were instrument error which is originated from measurement system and the form error of standard specimens. An instrument with a rotating table supported by an air bearing is calibrated using standard specimens. The phase of standard specimens was measured 12 times on the rotating table with rotating 30 in turn and its measurement magnification was set by 100000 times. As a result of data analysis of all the observations, read out at each of 144 orientations(per 2.5) from recorded datafiles, the error of the performance of the instrument and those of the standard specimens are evaluated and a systematic deviation of the instrument is determined. In the particular instrument used in the present experiment, the deviation of the instrument is determined with the accuracy of 15nm and those of standard specimens with the accuracy of 23, 13 n, respectively. The reproducibility of the instrument is investigated, too. If the instrument is calibrated by using the above standard specimens, then the accuracy of the measurement of roundness error can be improved to about 15nm.

Efffct of Material Removal per Tooth on the Circumferential Shape of Cylindrically Milled Parts (공구날당 소재제거량이 원통형 밀링가공물의 원주형상에 미치는 영향)

  • Kim Kwang Hee
    • Transactions of the Korean Society of Machine Tool Engineers
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    • v.13 no.5
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    • pp.62-66
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    • 2004
  • A study for investigating the effects of the cutting conditions(feed rate, radial depth of cut, cutting speed) and the tool diameter on the circumferential geometry of the cyl indrically end-mi1led workpiece is described. In this work, the circumferential geometry is characterized by the roundness error. Experimental results show that the circumferential geometry is directly affected by the material removal per tooth,which is defined as a function of the cutting speed, the feed rate and the radial depth of cut. And, the radial depth of cut is revealed to be the most critical condition among them. It is also found that the roundness error decreases when the tool diameter is larger under the same cutting conditions.

Chucking Compliance Compensation by Using Linear Motor (리니어 모터를 이용한 척킹 컴플라이언스 보상)

  • Lee, Seon-Gyu;Lee, Jin-Ho
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.26 no.1
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    • pp.15-22
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    • 2002
  • This paper introduces a compensating system for machining error, which is resulted from chucking with separated jaws. In machining the chucked cylindrical workpiece, the deterioration of machining accuracy, such as out-of-roundness is inevitable due to the variation of the radial compliance of the chuck workpiece system which is caused by the position of jaws with respect to the direction of the applied force. To compensate the chucking compliance induced error, firstly roundness profile of workpiece due to chucking compliance after machining needs to be predicted. Then using this predicted profile, the compensated tool feed trajectory can be generated. And by synchronizing the cutting tool feed system with workpiece rotation, the chucking compliance induced error can be compensated. To satisfy the condition that the cutting tool feed system must provide high speed and high position accuracy, brushless linear DC motor is used. In this study, firstly through the force-deflection experiment in workpiece chucked lathe, the variation of radial compliance of chuck workpiece system is obtained. Secondly using the mathematical equation and cutting experiment result, the predicted profile of workpiece and its compensation tool trajectory are generated. Thirdly the configuration of compensation system using linear motor is introduced, and to improve the system performance, PID controller is designed. Finally the tracking performance of system is examined by experiment. Through the real cutting experiment, roundness is significantly improved.

On-Machine Measurement System Development of Hole Accuracy using Machine Vision (머신비젼을 이용한 구멍 정밀도의 기상측정시스템 개발)

  • Kim, Min-Ho;Kim, Tae-Yeong
    • Journal of the Korean Society for Precision Engineering
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    • v.27 no.5
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    • pp.7-13
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    • 2010
  • The integrity and accuracy of the drilling hole are decided by positional error, diameter error, the roundness, the straightness, the cylindericity, size of the burr, the surface roundness and others. Among these parameters, positional error and diameter error have the most important parameters. The diameter error has been widely studied, but there has been little research done about the positional error due to the difficulty of measuring it. The measurement of hole location and diameter would be performed by CMM(Coordinate Measurement Machine). However, the usage of CMM requires much time and cost. In order to overcome the difficulties, we have developed a hole location and diameter error measuring device using machine vision. The developed measurement device attached to a CNC machine can determine hole quality quickly and easily.

Influence of fixed pressure on the machining accuracy of inner diameter of hollow shaft (고정압이 중공축 내경의 가공정밀도에 미치는 영향)

  • Jeon, Young-Seog;Jang, Sung-Min;Kang, Shin-Gil
    • Journal of the Korean Society of Manufacturing Technology Engineers
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    • v.19 no.3
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    • pp.381-387
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    • 2010
  • This paper presents a study of the influence of fixed pressure in turning. The effect of roundness error and diameter deformation were studied with respect to the fixed pressure applied inside the cylindrical work piece made by boring tool in CNC lathe. The boring tool used in this study is a tungsten carbide coated. The material of workpiece is SM45C and the machining method is dry cutting. Cutting conditions as cutting speed, feed rate and depth of cut are constant. Finally, the change of fixed pressure had influence on the roundness error and diameter deformation.