Abstract
An SMT machine has many working coordinate frames—the fiducial mark camera frame, component camera frame, machine table frame, PCB frame, and reference frame. Because of many influences such as mechanical dimension errors, machine assembling errors, and camera lens distortions, all frames on the SMT machine must be calibrated to compensate for these machine errors. This paper applies machine vision techniques to auto-calibrate an SMT machine, including frame transformations and nozzle compensation, bringing the accuracy of this system to within ±0.1 mm. The coordinate mapping from the camera frame to machine table frame is a quadratic form, while the other frame mappings use linear forms. The merits for this machine’s vision-based, auto-calibration methods are: (1) It has little calibration time, (2) It does not need expensive calibration instruments, and (3) Its expense is very low.
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References
Zupancic J (1994) Calibration of an SMT robot assembly cell. J Robot Syst 11:301–310
Woolstenhulme J, Lubofsky E (2000) Machine vision placement considerations. Surf Mount Tech 14:62–65
Butler DA, Pierson PK (1991) A distortion-correction scheme for industrial machine-vision applications. IEEE Trans Robotic Autom 7:546–551
Shen TS, Menq CH (2001) Automatic camera calibration for a multiple-sensor integrated coordinate measurement system. IEEE Trans Robotic Autom 17:502–507
Wang CC (1994) A low-cost calibration method for automated optical measuration using a video camera. Mach Vision Appl 7(4):259–266
Chatterjee C, Roychowdhury VP (2000) Algorithms for coplanar camera calibration. Mach Vision Appl 12:84–97
Chang YC, Reid JF (1996) RGB calibration for color image analysis in machine vision. IEEE Trans Image Process 5:1414–1422
Bose CB, Amir J (1990) Design of fiducials for accurate registration using machine vision. IEEE Trans Pattern Anal 12:1196–1200
Shih CL, Ruo CW, Hsu HT (2003) Locating and checking of BGA pin position using gray level. Int J Adv Manuf Tech (in press)
Acknowledgement
This work is supported by the National Science Council of Taiwan under Grant NSC 91-2212-E-011-055.
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Shih, CL., Ruo, CW. Auto-calibration of an SMT machine by machine vision. Int J Adv Manuf Technol 26, 243–250 (2005). https://doi.org/10.1007/s00170-003-1765-0
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DOI: https://doi.org/10.1007/s00170-003-1765-0