• Title/Summary/Keyword: On the Machine Measurement(OMM)

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A study of an OMM system for machined spherical form measurement using the volumetric error compensation of Machining Center (머시닝센터의 오차보상을 통한 구면 가공형상 측정 OMM 시스템 연구)

  • 이찬호;오창진;이응석;김성청
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 2000.11a
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    • pp.838-841
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    • 2000
  • To improve the accuracy of products and improve the product quality, we need to enhance the machining accuracy of the machine tools. To this point of view, measurement and inspection of finished part as well as error analysis of machine tools has been studied for last several decades. OMM(On the Machine Measurement) has been issued to alternate with CMM, pointing out disadvantages of high expenses and lots of setting time in CMM. In this paper, we study 1) the spherical surface manufacturing by volumetric error compensation of machine tool, 2) the system development of OMM without detaching work piece from a bed of machine tool after working. 3) the generation of the finished part profile by On the machine measurement. Furthermore, the output of OMM is compared with that of CMM, and verified the feasibility of the measurement system.

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The Development and Evaluation of OMM(On the Machine Measuring) System Using Scanning Probe (Scanning Probe를 이용한 OMM(On the Machine Measuring) 시스템 개발 및 평가)

  • Kim, S.H.;Kim, I.H.
    • Journal of the Korean Society for Precision Engineering
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    • v.13 no.10
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    • pp.71-77
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    • 1996
  • This paper describes the development of on the machine measuring(OMM) system which can directlry measure the three dimensional machined dimensilnal accuracy using scanning probe in milling machine. Two algolithms, continuous path(CP) measurement using UC program and CAD data assisted point to point(PTP) measurement, were developed regarding specification of scanning probe. The OMM system was contructed to verify the developed system suing the proposed algorithm, and actually measured three kinds of machined TV shadow mask molds. The developed system was evaluated it's repeatability and compared with the current measurement system of CMM(Coording Measuring Machine) in terms of relative accuracy and time reduction and productivity increase.

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Geometric Accuracy Measurement of Machined Surface Using the OMM (On the Machine Measurement) System

  • Kim, Sun-Ho;Lee, Seung-Woo;Kim, Dong-Hoon;Lee, An-Sung;Lim, Sun-Jong;Park, Kyoung-Taik
    • International Journal of Precision Engineering and Manufacturing
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    • v.4 no.4
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    • pp.57-63
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    • 2003
  • Machining information such as form accuracy and surface roughness is an important factor for manufacturing precise parts. To this regard, OMM (On the Machine Measurement) has been researched for last several decades to alternate CMM (Coordinate Measurement Machine) process. In this research, the OMM system with a laser displacement sensor was developed for measuring form accuracy and surface roughness of the machined workpiece on the machine tool. The surface roughness was estimated comparing the sensory signal with the reference data measured from master specimen. Also, form accuracy was determined from the moving averaged raw data. In addition, the geometric error map constructed beforehand using the geometric errors of the machine tool was used to compensate the obtained form accuracy. The overall performance was compared with CMM result, and verified the feasibility of the measurement system.

Development of On-the-Machine Measurement(OMM) System (기상측정(機上測定) 시스템 개발)

  • Lee, Seung-Woo;Kim, Sun-Ho
    • IE interfaces
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    • v.11 no.1
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    • pp.199-205
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    • 1998
  • This paper describes the development of on-the-machine measuring(OMM) system which can directly measure the two and three dimensional machined accuracy using a scanning probe in milling machine. Two algorithms, NC program based continuous path(CP) measurement and CAD data assisted point to point(PTP) measurement, are developed for three dimensional measurements, with consideration of the characteristics of the scanning probe. The algorithms are used to develop an auto measuring system. The delveloped system is compared with the CMM (Coordinate Measuring Machine) in terms of accuracy and repeatability. The OMM system is expected to realize measurement time reduction and hence result in high productivity.

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The OMM system for machined form and surface roughness measurement concerned with volumetric error (기계 체적오차가 고려된 가공형상-거칠기 측정 OMM 시스템)

  • 이상준;김선호;김옥현
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 2000.05a
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    • pp.681-686
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    • 2000
  • Machining information such as machined form and surface roughness accuracy is an important factor for manufacturing precise parts. To this regard, OMM(On the Machine Measurement) has been issued for last several decades to alternate with CMM. In this research, measuring system consisting of a laser probe is developed for machined form and surface roughness measurement on the machine tool. The obtained machined form accuracy is compared with reference one defined in CAD model. The measured surface roughness data is compared with measured master surface beforehand. Furthermore, using the pre-defined volumetric error map approach compensates the geometric accuracy of the machine tool. The overall performance is compared with CMM, and verified the feasibility of the measurement system.

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The OMM System for Machined Form and Surface Roughness Measurement Concerned with Volumetric Error (기계 체적오차가 고려된 가공형상-거칠기 측정 OMM 시스템)

  • 이상준;김선호;김옥현
    • Journal of the Korean Society for Precision Engineering
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    • v.17 no.7
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    • pp.232-240
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    • 2000
  • Machining information such as machined form and surface roughness accuracy is an important factor for manufacturing precise parts. To this regard, OMM(On the Machine Measurement) has been issued for last several decades to alternate with CMM. In this research, measuring system consisting of a laser probe is developed for machined form and surface roughness measurement on the machine tool. The obtained machined form accuracy is compared with reference one defined in CAD model. The measured surface roughness data is compared with measured master surface beforehand. Furthermore, using the pre-defined volumetric error map approach compensates the geometric accuracy of the machine tool. The overall performance is compared with CMM, and verified the feasibility of the measurement system.

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Ultra Miniature Eddy Current Sensor with 3 Axes for On-Machine-Measurement (기상측정용 3축 구조의 초소형 와전류 센서 개발 및 평가)

  • Kim, Sun-Ho
    • Journal of the Korean Society for Precision Engineering
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    • v.27 no.3
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    • pp.27-32
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    • 2010
  • The OMM(On-Machine-Measurement) system has many advantages compare to conventional measurement in the way the time and cost. But, the sensor suitable to OMM system is restrictive use. Touch trigger probe sensor has long time for measurement and non-contact sensor has directional demerit. Because the long mechanical parts such as gear and lead screw for pump, injector and machine tools has big and heavy, unclamp and transferring for measurement in machining process is very difficult. This paper presents a development of ultra miniature eddy current displacement sensor with 3 axes for On-Machine-Measurement system. The accuracy of the sensor is experimentally proved in the grinding machine. In experimental results, the accuracy has under ${\pm}5\;{\mu}m$.

Error Prediction Considering the Measurement Direction in OMM System (OMM 시스템에서 측정방향을 고려한 가공물의 오차평가)

  • 최진필;이상조;권혁동
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 2002.05a
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    • pp.632-635
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    • 2002
  • In this paper, a general procedure to determine machine tool errors from the on-machine measurement (OMM) data is described. First, a parameterized error model of a machine tool is illustrated by approximating error components as linear function of axis positions, and a modified error model is proposed which includes backlash effects. To determine the unknown model coefficient vectors of the forward and backward error model, an artifact with 8 cutes is made and calibrated on CMM. Then, lower-left and upper-right cube corners are measured with a touch-trigger probe mounted on the machine tool spindle. Measured error data are used to determine the coefficient vectors. The positioning errors in the XY plane at the fixed z position are simulated for the forward and backward error model.

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A Study on a Hartmann Test of Optical Mirror for On-Machine Measurement of Polishing machine (광학면 연마기의 OMM을 위한 Hartmann Test 방법 연구)

  • 김옥현;이응석;오창진;김용관
    • Journal of the Korean Society for Precision Engineering
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    • v.21 no.1
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    • pp.40-45
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    • 2004
  • Recently, aspheric optical lenses and mirrors, which are harder to manufacture and measure than the conventional spherical ones, are widely used, particularly in electronic fabrication process. Generally, interferometric optical method is used for the measurement of spherical optical surface. However, the interferometric method for aspheric surface measurement is difficult because it needs a precise null corrector and strict environmental conditions such as constant temperature, humidity and vibrations. We have been studied on the manufacturing of aspheric optics to improve the surface profile accuracy and productivity using a corrective polishing process. For the corrective polishing, a practical method of On-Machine Measurement (OMM) is required. For this purpose, an optical OMM system has been studied using the Shach-Hartmann test, which is very robust to the practical polishing environment. The wavefront has been reconstructed from the measured data using the primary aberration polynomial function by the least squares fitting. The measured result of the OMM system shows that the maximum deviation is less than 200 nm for the one of commercial Fizeau interferometer Wyko 6000.

The Error Source Analysis of Measuring Data of OMM System (OMM 시스템의 측정오차 원인분석 및 대책)

  • 이상준;김선호;김옥현
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 1997.04a
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    • pp.73-77
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    • 1997
  • This paper describes the analysis of measuring error of on the machine measuring(OMM) system which can directly measure the three dimensional machined free surface dimension using scanning probe on milling machine. 21 inch TV shadow mask mould was measured using PTP(point to point)measurement algorithm at pallet clamped and unclamped state on OMM system, and using coordinate measuring machine(CMM) one after another. The OMM system was evaluated probe error, stylus contact error, center shift error, repeatability and so on. Consequencely, the conclusion derived that elastic displacement of pallet had effect on measuring error mainly, and pallet design and setup method would be important.

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