• International Journal of Precision Engineering and Manufacturing
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• v.6 no.4
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• pp.14-20
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• 2005

In this paper, a new field of metrology called 'precision nanometrology' is presented. The 'precision nanometrology' is the result of evolutions of the traditional 'precision metrology' and the new 'nanometrology'. 'Precision nanometrology' is defined here as the science of dimensional measurement and motion measurement with 100 nm to 0.1 nm resolution/uncertainty within a range of micrometer to meter. The definition is based on the fact that nanometrology in nanoengineering and the precision industries, such as semiconductor industry, precision machine tool industry, precision instrument industry, is not only concerned with the measurement resolution and/or uncertainty but also the range of measurement. It should also be pointed out that most of the measurement objects in nanoengineering have dimensions larger than 1 micrometer. After explaining the definition of precision nanometrology, the paper provides several examples showing the critical roles of precision nanometrology in precision nanosystems, including nanometrology system, nanofabrication system, and nanomechatronics system.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1993.10a
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• pp.279-285
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• 1993

This paper presents a precision automatic measuring system for ball screw Pitch. Ball screw is mounted on a precision indexing table, and the ball screw pitch is measured via magnetic scale, where the indexing and measurement are performed by a PC. For precision indexing of ball screw, direct driven motor is coupled to the designed dead and live centers; the performance of the centers are assessed with a precision master sylinder,such as radial motion,tilt motion, and axial motions. An error compensation model is constructed for the measurement system of ball screw pitch, where the error motions of indexing system as well as the scale measurement system are combined to give the measurement error for the ball screw. The developed system proposes an automated precision measurement system for manufacturers and users of ball screw.

• Journal of the Korean Society for Precision Engineering
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• v.21 no.10
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• pp.102-108
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• 2004

In this paper, we studied a vibration problem that is critical and common to most precision measurement systems. For micro mechanical part measurements, results obtained from the vision-based precision measurement system may contain errors due to the vibration. In order to defeat this generic problem, for the current study, a PC based image processing technique was used first, to assess the effect of the vibration to the precision measurement and second, to develop an in-situ calibration algorithm that automatically compensate the measurement results in real time. We used a set of stereoscopic CCD cameras to acquire the images for the dimensional measurement and the reference measurement. The mapping function was obtained through the in-situ calibration to compensate the measurement results and the statistical analysis for the actual results is provided in the paper. Based on the current statistical study, it is expected to obtain high precision results for the micro measurement systems.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2001.04a
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• pp.131-134
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• 2001

The three-dimensional precision measurement technology for industry product of middle and/or large scale has been developed. Theodolite measurement system which is one of the technology is widely used in aerospace industry. This paper describes measurement method and results for spacecraft structure test model by using the measurement system. And structural stability for STM is desribed through the comparison between design values and measured values.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.11 no.4
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• pp.55-61
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• 2012

Very important content in performance evaluation of machine tool is positioning accuracy and repeatability precision measurements of feed mechanism. A study analyses the measurement method and uncertainty factors by ISO-based test method. Reliable results can't be derived without the notion of measurement uncertainty. The reason is that the measured value includes a lot of uncertain factors. Finding the factor that affects the measurement of parameter is important for estimation of measurement precision. In this paper, the evaluation of uncertainty analysis about positioning accuracy and repeatability precision measurements of high precision feed mechanism is presented to evaluate the important factors of uncertainty.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2000.05a
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• pp.607-612
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• 2000

Roundness measurement method using three displacement sensors makes in-process roundness measurement possible on the NC machine because it eliminates the vibration signal and eccentricity signal from measured roundness signal from the workpiece. But if measured signals contain noises, high precision measurement of the roundness isn't possible. In this study, a high precision in-process roundness measurement system is developed, which applies a Kalman filter to the roundness measurement method using three displacement sensors and can be used to measure vibration of the spindle.

• Journal of Korea Technology Innovation Society
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• v.4 no.1
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• pp.110-126
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• 2001

In this study, we survey the demand of precision measurement technology including instrument and technical manpower in Korean industry and institution. Also this study is purposed to improve the metrological technology by suggesting the solution of technical problems.

• Journal of the Korean Society for Precision Engineering
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• v.20 no.7
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• pp.99-104
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• 2003

A precision displacement measurement system of 3-DOF micro motions is proposed in this paper. The measurement system is composed of two diode lasers, two quadratic PSDs, two beam splitters and a sphere whose surface is highly reflective. In this measurement system, the sphere reflector is mounted on the platform of positioning devices whose 3-DOF translational motions are to be measured, and the sensitive areas of two PSDs are oriented toward the center point of the sphere reflector. Each laser beam emitted from two diode laser sources is reflected at the surface of sphere and arrives at two PSDs. Each PSD serves as a 2-dimensional sensor, providing the information on the 3-dimensional position of the sphere. In this paper, we model the relationship between the outputs of two PSDs and 3-DOF translational motions of the sphere mounted on the object. Based on a deduced measurement model, we perform measurement simulation and evaluate the performance of the proposed measurement system: linearity, sensitivity, and measurement error. The simulation results show that the proposed measurement system can be valid means of precision displacement measurement of 3-dimensional micro motions.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2002.05a
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• pp.195-198
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• 2002

Demand for high precision measurement of large area is increasing in many industrial fields. White-light Scanning Interferometer(WSI) is a well-known method for 3D profile measurement. However WSI has some limitations in a measurement range because of the sensing mechanism. Therefore, in this paper we use a heterodyne laser interferometer to get over the limitations of a short measurement range in WSI, We suggest a new WSI system combined with heterodyne laser interferometer. This system is aimed at eliminating Abbe error with measuring the focus point directly. With the use of triggering functionality of WSI, we can use this system as a probe of a precision stage such as a probe of CMM. The suggested system gives a repeatability of 87 nm in the absolute distance measurement test under the laboratory environment.

• Journal of the Korean Society for Precision Engineering
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• v.17 no.1
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• pp.129-137
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• 2000

In this paper, a new method of noncontact measurement has been developed for a 3 dimensional topography in semiconductor wafer, implementing a new optical probe based on the precision defocus measurement. The developed technique consists of the new optical probe, precision stages, and the measurement/control system. The basic principle of the technique is to use the reflected slit beam from the specimen surface, and to measure the deviation of the specimen surface. The defocusing distance can be measured by the reflected slit beam, where the defocused image is measured by the proposed optical probe, giving very high resolution. The distance measuring formula has been proposed for the developed probe, using the laws of geometric optics. The precision calibration technique has been applied, giving about 10 nanometer resolution and 72 nanometer of four sigma uncertainty. In order to quantitize the micro pattern in the specimen surface, some efficient analysis algorithms have been developed to analyse the 3D topography pattern and some parameters of the surface. The developed system has been successfully applied to measure the wafer surface, demonstrating the line scanning feature and excellent 3 dimensional measurement capability.