Application of automatic optical inspection technology

Automatic optical inspection (AOI) is a new inspection technology, but it is developing rapidly. Many manufacturers have introduced AOI testing equipment. Take SMT detection as an example. During automatic detection, the machine will automatically scan the PCB through the camera, collect images, and compare the detected solder joints with the qualified parameters in the database. After image processing, check the defects on the PCB, and display / mark the defects through the display or automatic mark for repair by maintenance personnel.
With the rapid development of electronic technology, image sensing technology and computer technology, the use of automatic optical (visual) detection technology of surface defects based on optical image sensing to replace manual visual detection of surface defects has gradually become an important means of surface defect detection, because this method has the advantages of automation, non-contact, high speed, high precision and stability.
The earliest method used for PCB inspection was manual visual inspection. Due to the requirements of high-density circuit wiring and high output, manual visual inspection cannot meet the reliability requirements. The best solution for repetitive, monotonous and rigorous inspection tasks is to use an automatic optical inspection system. AOI can meet the overall inspection of PCB on the production line. The AOI system can detect the following errors: missing components, wrong polarity of tantalum capacitor, incorrect position or deflection of welding pin, bending or folding of welding pin, excessive or insufficient soldering tin, welding bridge or false welding. AOI can not only check the defects that cannot be detected by manual visual inspection, but also detect the components and solder joints that cannot be touched by the needle bed in online inspection, thus improving the defect coverage. AOI can also collect the work quality and defect types of each process in the production process, and feed them back to the process control personnel for analysis and management, so as to reduce the scrap rate of PCB.