A Study of Machine Vision in Inspecting Connectors of Surface-Mount Technology

• Main Authors: Lin Chou, 周霖
• Other Authors: Nai-Jian Wang
• Format: Others
• Language: zh-TW
• Published: 2013
• Online Access: http://ndltd.ncl.edu.tw/handle/76346569850462778238

碩士 === 國立臺灣科技大學 === 電機工程系 === 101 === 　With the trend of automation, manual vision inspection (MVI) has been gradually replaced by automatic optical inspection (AOI) for speeding up the production and reducing the cost of assembly nowadays. However, equipments are usually expensive, which will be a heavy burden for a small- amount demand R&D laboratory in a company. As for current choice of AOI equipments, customized ones are often more welcome due to the consideration of fitness and cost, rather than a universal learning system, especially when the objects to be tested are special or high precision. 　Our study focuses on developing an inspection system for a surface-mounted device receptacle connector, I-PEX 20474-030E, which is a high-cost and high-precision electronic component. The defects to be detected include component missing, skewing, wrong priority, component shifting, solder bridge, and missing solder. The proposed system is designed as an off-line inspection. Manual positioning is not required before detection to make the operation easy and simple and the total costs of equipments are kept low in our system. For the algorithms of the system, it is combined by mathematical algorithms and image processing technique. First the target object is obtained by fast connected component, and then the revised least square error method calculate the inclination angles of the object to help positioning the freely-placed connectors. After that, morphology and other image processing technique are applied for image analysis to detect the defects of the connectors. 　With 1920 images of test samples, the experimental results indicate that the detection rate of the proposed method for each defect is at 96.57%, and the overall false rate is 1.13%. The method has little interference of noise or changes in brightness, hence it can be said to be a reliable and stable real-time inspection system with simple and convenient operation.