대면적/고정밀 3차원 표면형상의 5자유도 정합법 개발 및 평가

이동혁(Dong-Hyeok Lee),안정화(Jung-Hwa Ahn),조남규(Nham Gyoo Cho) 한국생산제조학회 2014 한국생산제조학회지 Vol.23 No.2

In this paper, a new method is proposed for the five-degree-of-freedom precision alignment and stitching of three-dimensional surface-profile data sets. The control parameters for correcting thealignment error are calculated from the surface profile data for overlapped areas among the adjacent measuring areas by using the “least squares method” and “maximum lag position of cross correlation function.” To ensure the alignment and stitching reliability, the relationships betweenthe alignment uncertainty, overlapped area, and signal-to-noise level of the measured profile data are investigated. Based on the results of this uncertainty analysis, an appropriate size is proposed for the overlapped area according to the specimen’s surface texture and noise level.

Modelling and Optimisation of Up-and Down-Milling Processes for a Representative Pocket Feature

Mariana Dotcheva,Krassimir Dotchev,Ivan Popov 한국정밀공학회 2013 International Journal of Precision Engineering and Vol. No.

This paper presents the specifics of the two types of end-milling, up- and down-milling, in the context of process planning of a finishing operation for machining complex pocket features. An optimisation mechanism is used for a pocket type of end-milling operation with the aim of comparing the results from up- and down-milling. Two sets of cutting conditions have been generated and analysed for each type of end-milling- one with constant parameters for the entire tool path, derived from the worst case of cutting (representing the usual process planning approach) and another set representing the optimised process. The predicted results were verified through experiments. The optimized cutting parameters, when machining the critical corner, demonstrate the important changes in magnitude and direction of the radial cutting-tool deviation and surface error.

Surface profilometry of silicon wafers using wavelength-tuned phase-shifting interferometry

Fuqing Miao,안석영,문영훈,김양진 대한기계학회 2019 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.33 No.11

Surface profile is one of the key evaluation indexes in the optical industry. With the development of optical technology, wavelengthtuned phase-shifting interferometry has been widely used for measuring the surface profiles of optical components based on the high accuracy of this technique. However, coupling errors caused by higher harmonics and phase-shift errors may lead to systematic errors in the calculated phase. In this research, to suppress coupling errors effectively, we propose an 8N - 7 phase-shifting algorithm consisting of a novel polynomial window function and discrete Fourier transform. By locating eight multiple roots on the characteristic diagram, the polynomial window function of the proposed algorithm is derived based on the theory of characteristic polynomials. The characteristic polynomial of the 8N - 7 algorithm is estimated based on a Fourier representation. Phase errors are discussed and compared to the errors in other algorithms. The results indicate that the 8N - 7 algorithm has the smallest phase error among the compared algorithms and can compensate for up to sixth-order nonlinearity in phase measurements. Finally, the proposed algorithm was applied to profile the surface of a silicon wafer. The results revealed that the standard deviation across 20 experiments was 3.231 nm, which is much smaller than the standard deviations of conventional phase-shifting algorithms.

비구면 렌즈의 생산성 향상을 위한 최적가공조건선정

백승엽(S. Y. Baek),이해동(H. D. Lee),김성철(S. C. Kim),이은상(E. S. Lee) 한국정밀공학회 2006 한국정밀공학회 학술발표대회 논문집 Vol.2006 No.5월

To enhance the precision and productivity of ultra precision aspheric surface micro lens, the development of ultraprecision grinding system and process for the aspheric surface micro lens are described. In the work reported in this paper, an ultra-precision grinding system for manufacturing the aspheric surface micro lens was developed by considering the factors affecting the grinding surface roughness and profile accuracy. This paper deals with mirror grinding of an aspheric surface micro lens by resin bonded diamond wheel and spherical lens of BK7. The optimization of grinding conditions on ground surface roughness and profiles accuracy is investigated using the design of experiments.

휴대폰 카메라용 비구면 마이크로 렌즈 최적 연삭가공 평가

백승엽(Seung Yub Baek),이은상(Eun Sang Lee) 한국생산제조학회 2006 한국생산제조학회지 Vol.15 No.2

As consumers in optics, electronics, aerospace and electronics industry grow, the demand for ultra-precision aspheric surface lens increases higher. To enhance the precision and productivity of ultra precision aspheric surface micro lens, the development of ultra-precision grinding system and process for the aspheric surface micro lens are described. In the work reported in this paper, an ultra-precision grinding system for manufacturing the aspheric surface micro lens was developed by considering the factors affecting the ground surface roughness and profile accuracy. This paper deals with mirror grinding of an aspheric surface micro lens by resin bonded diamond wheel and spherical lens of BK7. The optimization of grinding conditions on ground surface roughness and profiles accuracy is investigated using the design of experiments.

태양 프로파일 예측 오차 최소화를 위한 보정 방법 및 블라인드 제어 전략

성윤복(Seong Yoon-Bok),여명석(Yeo Myoung-Souk),김광우(Kim Kwang-Woo) 대한건축학회 2012 대한건축학회논문집 Vol.28 No.4

The objective of this study is to deduce correction methods and control strategy that minimize solar profile prediction error to prevent glare caused by direct sunlight inlet. During the process of solar profile prediction, the major factors causing the errors are surface orientation and time. And because of this prediction error, the direct glare by the sunlight inlet may occur in blind control. In order to identify the accurate surface orientation based True North, correction methods utilizing a 3D measuring instrument and a protractor were suggested and verified through the field experiment. For solving the problems by the potential time errors, control strategy was proposed to divide the control sections using the calibrated control curve and this strategy was verified through the simulation. The proposed correction methods and control strategy in this research could prevent the direct glare all the time. And also these methods could maximize daylight and solar heat gain, because the blocked area on windows could be minimized.

구동오차 보상에 의한 정밀 표면형상 측정 기술

백상우(S.W. Baek),김민규(M. G. Kim),이동혁(D. H. Lee),조남규(N. G. Cho) 한국정밀공학회 2016 한국정밀공학회 학술발표대회 논문집 Vol.2016 No.5월

A Registration Method for Profi le Error Inspection of Complex Surface Under Minimum Zone Criterion

Gaoshan Tan,Liyan Zhang,Shenglan Liu 한국정밀공학회 2019 International Journal of Precision Engineering and Vol.20 No.7

Although registration of the measured model and the design model has been widely studied, it remains an open problem in complex surface profile error inspection. False rejection of some qualified parts is prone to occur due to the improper registration between the measured points and the nominal model. To solve this problem, we define a surface profile error metric in terms of a new range norm under minimum zone criterion. An optimal framework based on the range norm is proposed to find the registration pose of the measurement data set, in which the surface profile error is minimized. To deal with the computational intractability, the non-differentiable merit function is uniformly approximated by a smooth aggregation function, which can be effectively solved with the limited-memory Quasi-Newton method. Distinct numerical stability control and the active set selection mechanism are proposed to guarantee the accuracy and efficiency of the method. Experiments on a simulated and a real part are included to verify the superiority of the proposed method.

Development of Aspheric Surface Profilometry using Curvature Method

Korean Society for Precision Engineering 2015 International Journal of Precision Engineering and Vol.16 No.9

A curvature method is one promising possibility for the measurement of optical aspheric or freeform surface, which is the major part of an optical system, such as google glasses, and wearable devices. Increasing demand for highly accurate optical components requires accurate and efficient measurement techniques. In this paper, we have presented a method of aspheric surface reconstruction from curvature data by using white-light-interferometer as a curvature sensor. This sensor was found to be robust to mechanical position error and environmental noise via error diagnosis. The primary mirror of cassegrain type astronomical telescope was tested. The measurement results showed that white-light scanning interferomete was found to be suitable for measuring the aspheric surface profile as a curvature sensor.

Development of Aspheric Surface Profilometry using Curvature Method

김병창 한국정밀공학회 2015 International Journal of Precision Engineering and Vol. No.

A curvature method is one promising possibility for the measurement of optical aspheric or freeform surface, which is the major part of an optical system, such as google glasses, and wearable devices. Increasing demand for highly accurate optical components requires accurate and efficient measurement techniques. In this paper, we have presented a method of aspheric surface reconstruction from curvature data by using white-light-interferometer as a curvature sensor. This sensor was found to be robust to mechanical position error and environmental noise via error diagnosis. The primary mirror of cassegrain type astronomical telescope was tested. The measurement results showed that white-light scanning interferomete was found to be suitable for measuring the aspheric surface profile as a curvature sensor.