摘要
为了实现表面贴片技术(SMT)模板的高精度自动光学检测,提出了一种检测系统及对应的误差校正方法,提高了系统的检测精度;该方法首先由激光跟踪仪测量CCD相机的位置误差,之后采用移动最小二乘法拟合误差曲面,从而可对CCD相机的任意位置进行校正误差,并与样条插值法进行对比证明了本方法的优点;而系统在检测前需对SMT模板进行定位,每次的定位误差均不同,该误差由SMT模板的Mark点得出,并根据所求得的误差值经过齐次坐标变换从而校正SMT模板的定位误差;经实验验证系统在经过误差校正后对SMT模板上通孔的测量误差在0.032 mm以内,满足SMT模板的检测要求;故该系统可快速、精确、非接触地检测SMT模板,可有效提高PCB板的质量。
In order to realize high precision and automatic optical inspection of the SMT template, a detection system and its error correction method are proposed in this paper, thus the detection accuracy of the system is improved. This method firstly measures the position error of CCD camera by laser tracker, the error surface is fitted by moving least square method, so that it can correct the error of CCD camera in any position. The advantages of this method are proved by comparing with the spline interpolation method. The system needs to locate the SMT template positioning error before testing, and each time the positioning error is different, positioning error is calculated by the Mark point of the SMT template. Homogeneous transformation is carried out to correct the positioning error of SMT template according to the error value. The experiment result shows that the measurement error of the through hole on the SMT template is less than 0. 032 mm after the error correction, which satisfies the accuracy requirement of SMT template. The system can detect the SMT template quickly, accurately and noncontact, and improve the quality of PCB board effectively.
出处
《电子测量与仪器学报》
CSCD
北大核心
2016年第10期1468-1474,共7页
Journal of Electronic Measurement and Instrumentation
基金
国家自然基金委员会与中国民用航空局联合资助(U1433117)
中国民航科技重大专项(MHRD20130104)
中国民航大学天津市民用航空器适航与维修重点实验室开放基金资助项目
关键词
SMT模板
移动最小二乘法
误差曲面
定位误差
齐次坐标变换
SMT template
moving least square method
error surface
positioning error
homogeneous transformation
