Automated Optical Inspection (AOI) is a high-speed and high-precision optical image inspection system. Using machine vision as a standard inspection technology, it can improve the shortcomings of traditional human-based inspection using optical instruments. The application level includes high-tech inspections. Industrial R&D, manufacturing quality control, as well as national defense, people's livelihood, medical care, environmental protection, electric power and other fields.
Taking SMT inspection as an example, during automatic inspection, the machine automatically scans the PCB through the camera, collects images, and compares the tested solder joints with the qualified parameters in the database. The sign shows/marks the defect for repair by maintenance personnel.
AOI four detection positions:
(1) After solder paste printing, mainly check the situation of solder paste printing;
(2) After the chip components are placed, to check whether the patch is correct or not, errors can be found earlier and costs can be reduced;
(3) After the chip is placed, the inspection system can check for missing, offset, skewed chips and chip polarity errors on the PCB;
(4) After reflow soldering, at the end of the production line. The inspection system can detect missing, offset and skewed components and component polarity defects.
Among the four inspection positions of AOI, the purpose of inspection after solder paste printing, (chip) device placement and component placement is to prevent problems. Inspection at these positions can prevent the generation of defects; after reflow soldering The purpose of inspection is to find the problem. Preventing problems AOI is placed in front of the furnace, and problem AOI is placed behind the furnace.
