All PCB manufacturing companies employ a PCB inspection process when producing the articles for their customers. These days high-quality printed circuit boards (PCBs) have become a significant component of almost all sorts of electronic devices that we use in-home or hospitals.
Important PCB inspection procedures
These days manufacturers and PCB assemblers perform different types of PCB inspections at various stages of the manufacturing process. These inspections help detect the errors and faults on the spot so they can be corrected easily.
First Article PCB Inspection
The quality of production is directly associated with the functioning of SMT. Most commonly, the PCB manufacturers conduct the first article inspection before they start volume assembly and production.
Visual Inspection
The visual inspection usually means reviewing, analyzing, and inspecting the PCB components through naked eyes and detectors. Most times, the mistakes can be caught through the inspection; for example, component placements are analyzed along with solder paste printing. Naked eyes can easily detect if these components have been set up correctly. However, solder paste deposition and copper pad can not be assessed with eyes only; a Z high-degree detector would be needed for that.
Another part of visual inspection is analyzing the light reflected by the prism at reflow joints. These rays of light are reviewed with different perspectives to check the functionality of PCB.
Automated Optical Inspection
AOI is one of the most common visual inspection methods used by manufacturers to detect PCBs’ major defects. The procedure is conducted by using LED libraries, various light sources, along with cameras. The automated optical inspection takes the images of solder joints at different angles. These images are saved for comparison with a PCB board that’s designed and assembled correctly without fault.
The inspection highlights PCBs’ faults, such as scratches, nodes, component misalignments, and strains. Moreover, the system is good enough to detect missing components, if there are any. Nowadays, automated optical inspections are used by all high-profile PCB assembly services and manufacturers. The simple reason is that these inspections are reliable, detecting, and analyzing the faults without any hassle. Fortunately, there’s an evolution now, and simple AOI systems have been upgraded with 3D AOI for making PCB inspection an easy task.
Automated X-ray Inspection (AXI)
Most medical devices such as X-rays and pacemakers demand high-density PCB, so the apparatus’s design can be made small in size. Therefore, the technology SMT is considered the best solution for PCB assembly services and manufacturers for making dense and compact-sized PCBs.
With SMT technology, the package size of the PCB has been drastically reduced. With this new change, many complex components and faults emerged with the technology that cannot be detected with naked eyes. For instance, on a high-density PCB, there might be more than 14 thousand solder connections in a package featuring SMT.
Generally speaking, automated X-ray inspection is conducted to look through the solder joints to assess their missing balls, dispositions and component misalignments, and much more complexities. The X-ray inspection penetrates the compliments and takes the images for the analyses.