• Title/Summary/Keyword: Roundness measurement

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A Study on Tooth Micro-geometry Optimization of Planetary Gear for 5MW Wind Turbine Pitch Drive (5MW 풍력용 피치드라이브의 유성기어 Micro-geometry 최적화에 관한 연구)

  • Lee, In-Bum;Kim, Dong-Young;Xu, Zhe-Zhu;Lee, Do-Young;Lyu, Sung-Ki
    • Journal of the Korean Society of Manufacturing Process Engineers
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    • v.13 no.1
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    • pp.85-91
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    • 2014
  • The rotation of a spindle unit must be accurate for high-quality machining and to improve the quality of the machine tools. Therefore, the proper measurement of the rotation accuracy and ensuring a proper analysis are very important. Separate processes are necessary because spindle errors and roundness errors associated with the test balls can both factor into the measured rotation error values. We used three methods to discern test ball errors and analyzed which could be deemed as the most proper technique in a test of the rotation accuracy of the main spindle of a machine tool.

Precision in situ Measurement using Non-Contacting Capacitive Sensor with 4-Electrodes (비접촉식 4-전극형 전기용량 센서를 이용한 in situ 정밀측정)

  • Kim, Jae-Yeol;Lee, Lae-Duck;Park, Ki-Hyung;Ma, Sang-Dong;Yang, Dong-Jo
    • Journal of the Korean Society for Precision Engineering
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    • v.19 no.3
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    • pp.33-38
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    • 2002
  • To establish the national standard of capacitance, four main electrodes of the cross capacitor which were evaluated to linearity and roundness less the $\pm 1 \mu m$ respectively have to be adjusted symmetrically in an inner cylinder. Four LM shafts with diameter of 5 mm were installed between main electrodes of the cross capacitor, and the electrodes were adjusted, as the first step, by means of the measured capacitance. In the second step, the symmetrical adjustment up to $\pm 1.2\mu m$ was performed by using a ball sensor, ball-type movable sensor, non-contacting capacitive sensor and upper guard sensor which were developed in this project.

Development of Online Realtime Positioning Error Compensation System for CNC Machine Tools (CNC 공작기계용 온라인 실시간 위치오차 보정시스템의 개발)

  • Chung, Chae-Il;Kim, Jong-Won;Nam, Weon-Woo;Lee, Sang-Jo
    • Journal of the Korean Society for Precision Engineering
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    • v.16 no.10
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    • pp.45-52
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    • 1999
  • The online realtime positioning error compensation system 'SKY-PACS' is developed to correct geometric errors, thermal errors and tool deflection errors induced by cutting forces on the vertical machining center. 'SKY-PACS' communicates position commands and position compensation signals with the CNC controller at 100Hz, which is CNC control frequency. So the compensation procedure can be applied during axis movement. Using 'SKY-PACS', Maximum 1 axis positioning accuracy was corrected from 5{\mu}m$ to 2{\mu}m$and the squareness error of X-Y table was corrected from 51{\mu}m$/m to below 4{\mu}m$/m. The error compensation under the cutting condition is carried out by ISO10791-7. And the measurement of test-pieces shows that the roundness is corrected rom 8{\mu}m$ to below 5{\mu}m$.

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A Useful Technique for Measuring the 3-dimensional Positioning of a Rotating Object (회전체의 효과적인 3차원 위치오차 측정방법)

  • Lee, Eung-Seok;Wi, Hyeon-Gon;Jeong, Ju-No
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.21 no.6
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    • pp.918-924
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    • 1997
  • A method for measuring the accuracy of rotating objects was studied. Rotating axis errors are significant; such as the spindle error of a manufacturing machine which results in the surface roughness of machined work pieces. Three capacitance type displacement sensors were used to measure the rotating master ball position. The sensors were mounted to the three orthogonal points on the spindle axis. The measurement data were analyzed and shown for rotating spindle accuracy, not only for average roundness error but also for spindle volumetric positional error during the revolutions. This method is simple and economical for industrial field use with regular inspection of rotating machines using portable equipment. Measuring and analyzing time using this method takes only a couple of hours. This method can also measure microscopic amplitude and 3-dimensional direction of vibrating objects.

Measurement of Carbon Nanotube Agglomerates Size and Shape in Dilute Phase of a Fluidized Bed (유동층 반응기 희박상 내 탄소나노튜브 응집체의 크기 및 형상 측정)

  • Kim, Sung Won
    • Korean Chemical Engineering Research
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    • v.55 no.5
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    • pp.646-651
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    • 2017
  • Size and shape of carbon nanotube (CNT) agglomerates in the dilute phase of a bubbling fluidized bed ($0.15m\;i.d{\times}2.6m\;high$) have been determined by the laser sheet technique. Axial solid holdup distribution of the CNT particles showed S curve with dense phase and dilute phase in bubbling fluidization regime. Heywood diameter and Feret diameter of the CNT agglomerates in the dilute phase of bubbling fluidized bed increased with increasing gas velocity. The CNT particle number in the agglomerates increased with increasing of gas velocity. Aspect ratio increased and circularity, roundness and solidity decreased with increasing of gas velocity. A possible mechanism of agglomerates formation was proposed based on the obtained information.

Development of the hot ring rolling processes for multilayered ring parts with a large outer diameter (외경이 큰 환형 부품의 다중형상 열간 링 롤링 공정의 개발)

  • Kim, Kyung-Ryool;Kim, Young-Suk
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.16 no.2
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    • pp.952-962
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    • 2015
  • In this study, multilayered rings with a large outer diameter have been developed using a hot ring rolling process. The ring rolling process has been analyzed by rigid plastic finite element analyses (FEA) using the AFDEX2D and AFDEX3D/HEXA/RING simulators, where the finite element meshes received severe plastic deformation are remeshed into a fine mesh-size using a dual-mesh system. According to the simulated results, the design variables of the multilayered rings were determined and real tests were conducted to check the validity of the simulation results. By adopting the hot ring rolling process, the input weight of raw materials was reduced by 40% against the conventional hot forging process and that the recovery rate was increased by 24%. The measurement of the averaged roundness was satisfied within 0.5 mm for both the inner and outer diameters. Moreover, the hot ring rolling processes yielded 1.49 Cpk for the outer-diameter and 0.84 Cpk 0.84 for the inner-diameter.

A Study on the Measurement of Physical Properties for Miscellaneous Cereal Crops Sorting (잡곡 선별을 위한 물성 측정에 관한 연구)

  • Kim, Hoon;Lee, Hyo-Jai;Han, Jae Woong
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.21 no.10
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    • pp.354-360
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    • 2020
  • This study examined the factors for sorting miscellaneous cereal crops using a rice-sorting device by analyzing the physical characteristics according to the moisture content. The initial moisture contents of miscellaneous cereal were 16.3, 19.8, and 16.5%, respectively. The samples were used in the experiment after drying to five levels. The width, length, and area of the samples increased with increasing moisture content except for the roundness, and all the prediction models were developed with a first-order linear equation. The bulk density of Italian millet and sorghum increased with increasing moisture content, whereas the bulk density of common millet was unaffected by the change in moisture content. The terminal velocity of the samples increased with increasing moisture content, and a first-order linear equation was used to develop the prediction models. The measured physical properties of the miscellaneous cereal crops based on the changes in the moisture content could be expressed using a first-order experimental model equation. Therefore, the rice-sorting device could be applied to the terminal velocity, but the other device applying the geometrical characteristics and bulk density was required to change the design of the process depending on the type of grain.