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Measurement and Correction of PCB Alignment Error for Screen Printer Using Machine Vision (2)  

신동원 (금오공과대학교 기계공학부)
Publication Information
Journal of the Korean Society for Precision Engineering / v.20, no.6, 2003 , pp. 96-104 More about this Journal
Abstract
This paper presents the measurement and correction method of PCB alignment errors for PCB screen printer. Electronic equipment is getting smaller and yet must satisfy high performance standard. Therefore, there is a great demand for PCB with high density. However conventional PCB screen printer doesn't have enough accuracy to accommodate the demand for high-resolution circuit pattern and high-density mounting capacity of electronic chips. It is because the alignment errors of PCB occur when it is loaded to the screen printer. Therefore, this study focuses on the development of the system which is able to measure and correct alignment errors with high-accuracy. An automatic optical inspection part measures the PCB alignment errors using machine vision, and the high-accuracy 3-axis stage makes correction for these errors. This system used two CCD cameras to get images of two fiducial marks of PCB. The centers of fiducial marks are obtained by using moment, gradient method. The first method is calculating the centroid by using first moment of blob, and the latter method is calculating the center of the circle whose equation is obtained by curve-fitting the boundaries of fiducial mark. The operating system used to implement the whole set-up is carried in Window 98 (or NT) environment. Finally we implemented this system to PCB screen printer.
Keywords
Screen Printer; PCB; Alignment Error; Fiducial Mark; Machine Vision;
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  • Reference
1 'Applied Technology: Screen Printer Helps Improve Production Consistency and Quality Goals,' Electronic packaging and production, Vol. 39, No. 7, pp. 55-56, 1999
2 Teoh, E. K., Mital, D. P., Lee, B. W., Wee, L. K., 'Automated visual inspection of surface mount PCBs,' Proceeding of IECON'90(16th Annual Conference of IEEE Industrial Electronics Society), pp. 576-580, 1990   DOI
3 Ahmadi, R. H., Kouvelis, P., 'Design of electronic assembly lines: An analytical framework and its application,' European Journal of Operational Research, Vol. 115, No. 1, pp. 113-136, 1999   DOI   ScienceOn
4 Alvi, Mohammed I., Giachetti, Ronald E., 'An object-oriented information model for manufacturability analysis of printed circuit board,' COMPUTERS IN INDUSTRY, Vol. 45, No. 2, pp. 177-196, 2001   DOI   ScienceOn
5 Gonzalez, R. C., Wood, R. E., Digital Image Processing, Addison Wesley
6 Park, Jae-Sung, Park, Heui-Jae, Kim, Ku-Young, 'Development of Managing System of Vision Probe for CMM,' Proc. of KSPE Autumn Annual Meeting 1996, pp. 501-505, 1996   과학기술학회마을
7 NALWA, VISHVJIT S., BINFORD, THOMAS O., 'On Detecting Edges,' IEEE Trans, Pattern Anal. Machine Intell., Vol. PAMI-8, No. 6, pp. 699-714, Nov. 1986   DOI
8 Otsu, N., 'A Threshold Selection Method from Gray Level Histogram,' IEEE Transactions on Syst, Man and Cyber, Vol. SMC-9, No. 1, pp. 62-66, 1979
9 Parker, J. R., Algorithms for Image Processing and Computer Vision, John Wiley & Sons, 1997
10 Shin, Dongwon, Kim, Chon-Whan, 'Measurement and Correction of PCB Alignment Error for Screen Printer Using Machine Vision,' Proc. of KSPE Spring Annual Meeting 2000, pp. 347-350, 2000