Design And Implementation Of Size Detection Method For Printed Circuit Board

In recent years,with the development of technology and the improvement of automatic measurement,precision and speed requirements for printed circuit board size measurement is higher and higher.In numerous carrier size measurement,by CCD sensor,optical imaging system,data acquisition and processing system of automatic optical measurement device,has many characteristics,such as high measurement precision,convenient and flexible application,is the existing mechanical instrument can not reach.So in the field of printed circuit board surface testing is widely used.This paper first introduces the developing situation of measurement technology at home and abroad.Analyzes the characteristic of automatic optical inspection technology;Break through the traditional PCB test technology,two straight line edge detection distance,the shape of the arc size detection method.This paper proposes a new automatic optical inspection technology,in accordance with the information provided by the customer,first,to get customers expected characteristic shape,matching point information.secondly by the method of digital image processing,image smoothing processing of CCD scanning,part out of the hole and the appearance of PCB,to extract the contour boundary scan images.and Then the matching point according to the customer information,matching the CCD scanning image and customer expectations shape,and obtain customer expectations shape around ±10mil printed circuit board shape edge pixels within the scope of information.finally through the analysis of customer expectations and scan images shape dimension deviation and CPK indices such as process capability index,so as to realize the purpose of rapid on-line automatic testing dimension deviation.Based on the Windows XP operating system,using VB 6.0 software platform,the realization of the software is completed.After the completion of the system,the system test and performance analysis are completed.In the actual production of a variety of possible cases,the system can detect target complete appearance size accurate,stable and meet the design requirements.