Research On PCBA Defect Detection Application Based On AO

With the rapid development of military industry and aerospace industry,electronic products tend to be integrated and high-quality.Although the manufacturing process and reliability of electronic products have been steadily improved,there are more and more kinds of welding defects in the manufacturing process of electronic products.PCBA(Printed Circuit Board Assembly)board is a popular name for PCB empty board after SMT(Surface Mount Technology)assembly or DIP(Dual In-line Package)plug-in,referred to as PCBA for short.In order to prevent products with welding defects from continuing to circulate during the production process,it is necessary to have complete quality management and testing methods to reduce the immeasurable risk.Automatic optical inspection technology(Automated Optical Inspection,AOI)is getting more and more attention because automatic optical inspection technology obtains effective data of components from captured images as well as processes and analyzes relevant data to complete the detection of related targets.This paper takes the AOI inspection of the soldering quality of components after reflow soldering of PCBA board in the actual production of enterprises as the research background instead of manual visual inspection,and studies the application of AOI system for component welding quality inspection in SMT assembly production.Firstly,this paper analyzes the research status of AOI technology at home and abroad,expounds the principle of PCB defect detection and its application in SMT production line,and accomplish the obtaining of the coordinate position information of actual PCB components and the detection module positioning during automatic detection,according to PCBA data preprocessing and circle detection algorithm.Secondly,image preprocessing and PCB defect detection are carried out,and the algorithms are analyzed and studied which are image filtering,image clipping,image histogram calculation and binarization etc.,so that the collected PCBA images can be processed pertinently.Fast classification,identification and detection of different defects of components are realized based on IPC data matching library and defect identification module.Furthermore,Using onedimensional and two-dimensional judgment module and display system,the defect detection and the display and data output of the detection results are finally realized.Finally,in the application software inspection in our institute,the application research and defect display of PCB solder joint detection shows that,At present,the detection of QFP(Quad Flat Package)device pins and resistive and capacitive device polarity pins have been realized,which improves the accuracy and speed of welding detection,and has a feedback effect on the coplanarity of material device pins in the material preparation area.The application and research of this system is of great significance,and the reliability of control equipment can be further improved by combining with the test of PCB’s later electrical performance,thus improving SMT production efficiency,shortening process flow and reducing artificial quality problems.It has a wide application prospect in domestic military enterprises.