When manufacturing PCBs, it is important to conduct inspections at every stage. This ultimately helps in identifying and correcting defects in the PCB, here are some ways to identify PCB defects:
Visual inspection: Visual inspection is the most common type of inspection during PCB assembly. Special equipment can be equipped for visual inspection according to the inspection objectives. Reflowed solder joints on PCBs are often inspected using prisms, which help identify various manufacturing defects. Using prism spectroscopy, incident light can be reflected off the PCB or PCB joints to understand issues in PCB design and contours.
X-ray inspection (AXI): Inspect components, welding, component misalignment, etc. Various faults may occur after mass production. With AXI technology, X-rays are shined directly onto the PCB assembly, which uses X-ray absorption to produce an image. X-ray inspection helps identify a variety of defects in wiring assemblies, voids and solder joints, semiconductor packages, and more.
Automated optical inspection (AOI): During the automated optical inspection process, a single or multiple cameras are used to scan the PCB. The camera stores images of various parts at different angles and positions. These images can then be analyzed by designers or engineers during the PCB assembly process, which will help detect defects such as scratches, stains, marks, and other dimensional defects. With this approach we can also identify skewed or incorrect components. Therefore, the system can use various 3D AOIs to detect the height and width of the PCB as well as the different micro-components used on the PCB.