• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.10a
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• pp.208-211
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• 2005

The volumetric interferometer, which uses the interference of wavefronts emitted from two single mode fibers, measures the target position in 3-D. In this paper, we suggest a new calculation method which doesn't need a non-linear optimization and an initial guess. We find the relationship between the coefficients of the Zernike polynomials for a spherical wavefront and its center and reconstruct a spherical wavefront by using the Zernike polynomials from two interference fringes like a lateral shearing interferometer. The target position can be obtained from the coefficients of the Zernike polynomials of the reconstructed wavefront. We can get the target position in 3-D with $sub-{\mu}m$ errors in a simulation.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2003.06a
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• pp.268-271
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• 2003

The Volumetric Interferometer using two spherical wavefronts emitted from the ends of two single mode fibers has been suggested to measure 3-dimensional absolute coordinates. In this paper, we try to improve the performance of the volumetric interferometer using multi-CCDs. We get coordinates matching matrixes between CCDs and can obtain more information in the space with multi-CCDs. Also we find out the best arrangement of multi-CCDs by computer simulations. In the simulation we can know that it will be better to increase the distance between CCDs to improve performance. For the performance test, we do a repeatability test, a comparison test with 2-D stage and the self-calibration using artifact.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2002.10a
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• pp.387-390
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• 2002

In this paper, we accomplish uncertainty evaluation and performance test of the volumetric interferometer using two spherical wavefronts emitted from the ends of two single mode fibers. We verify that the volumetric interferometer has the volume uncertainty of 690nm through the error analysis and it has the resolution of 0.1 0.1$\mu\textrm{m}$ for x axis which is the same order of repeatability for x axis. Also, we obtain the systematic error of $1\mu\textrm{m}$ for $60\times 60\times 20 mm^3$ working volume using self-calibration with an artifact plate.

• Journal of the Korean Society for Precision Engineering
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• v.11 no.4
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• pp.158-164
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• 1994

A volumetric error compensation method was stueide with measuring systematic error of a Coordinate Measuring Machine(CMM). The volumetric error equations were proposed for a Moving Bridge type CMM. Using the error equations, error vectors in the measuring volume were corrected by a software method. The CMM was controlled by the compensation program separately in the measuring and moving function of the CMM proving. The linear accuracy of the CMM was measured by the Laser Interferometer and compared with the data before the volumetric error compensation. This method was proved as low cost and effective to reduce the systematic error of the CMM, as no hardware modification is required.

• Korean Journal of Optics and Photonics
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• v.13 no.6
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• pp.521-529
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• 2002

We have recently proposed the new concept of a phase-measuring volumetric interferometer that enables us to accurately measure the xyz-coordinates of the probe without metrology frames. The interferometer is composed of a movable target and a fixed photo-detector array. The target is made of point diffraction sources to emit two spherical wavefronts, whose interference is monitored by an array of photo-detectors. Phase shifting is applied to obtain the precise phase values of the photo-detectors. Then the measured phases are fitted to a geometric model of multilateration so as to determine the xyz-location of the target by minimizing least square errors. The proposed interferometer has been designed and built with a volumetric uncertainty of less than 1.0 $\mu\textrm{m}$ within a cubic working volume of side 120 mm. Here, in this paper, we also present error sources, an evaluated uncertainty, and test results from the prototype system. The self-calibration of two-dimensional precision metrology stages is applied to test the performance of the interferometer.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1994.10a
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• pp.260-265
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• 1994

Efforts have been devoted to developing rapid and accurate methods for measuring the errors of machine tools. The method os measurement and calibration of machine tool errors should be general and efficient. The objective of this study is to show in detail the full sequence from the measurement of errors factors to the verification of the positioning accuracy after compensation for the volumetric error. In this paper, we described the steps in measuring the volumetric error parameters, a general error model composed of error parameters, temperature, and the desired position. The validity of the error calibration methods proposed in this paper was tested using a vertical 3-axis CNC machine with a laser interferometer and a ball bar.

• Proceedings of the Optical Society of Korea Conference
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• 2004.07a
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• pp.80-81
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• 2004

• Proceedings of the Optical Society of Korea Conference
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• 2005.07a
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• pp.244-245
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• 2005

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2000.05a
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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

• Transactions of the Korean Society of Mechanical Engineers
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• v.17 no.6
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• pp.1431-1440
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• 1993

This paper presents a new NC machine performance test and calibration system. In order to measure NC machine erros in simpler, and less time-comsuming way, some indirect measuring systems such as circular disk system and double ball bar system have been developed instead of laser interferometer. But these indirect measuring systems have shown their limits in identifying each of NC machine error sources in absolute numerical value. Therefore, we developed an unique NC machine error measurement system which provides a simple measuring process like other conventional indirect methods and still can indentify each of NC machine error sources in absolute numerical value.