In today’s context, a small PCB can potentially contain thousands of solder joints and numerous tiny components. The increased complexity leads to higher possibilities of errors. When standard visual inspections are insufficient to detect minute defects in densely packed circuit boards, technologies like Automated Optical Inspection (AOI) aid in providing deeper insights and accuracy.

What is AOI?

Automated Optical Inspection (AOI) is a visual quality control method used to identify defects that may occur during the manufacturing and assembly stages of PCBs. In this technology, cameras scan the circuit board to inspect various surface feature defects such as stains, scratches, open circuits, and short circuits. Additionally, it can also identify missing, incorrect, or improperly placed components.

PCB manufacturers will pass the PCB through AOI equipment after all components have been placed and then run it again after the soldering is completed. Throughout the process, the cameras capture multiple images that are used to generate a standard, often referred to as a golden standard, which represents a successfully assembled circuit board.

During subsequent production runs, AOI scans new images and compares them to the existing golden standard. When it encounters areas that do not meet the standard, it identifies potential defects in those areas. Later, technicians identify these errors and find possible solutions to correct them.