Practical method to use the AOI system at present

This issue has both pros and cons. For electronic assembly industries that require a larger number of stable production, AOI is indeed needed to help production inspections. But the question is whether AOI inspection equipment can screen out all components assembly problems, it is a dilemma. For traditional SMT parts, the pins are all around the parts body, so it is indeed feasible to carry out AOI inspection. However, when the AOI for SMT assembly gradually became popular, another trend emerged, that is, PCB design began to use a large number of array-type SMT parts, such as: CSP, BGA, etc. The emergence of this kind of parts is due to the complexity of the functions of electronic products and the increase of contact pins.

The pins of these parts are right below the parts. If the general AOI system is used, the soldering defects cannot be fully detected, and the problem can not be detected quickly if the penetrating X-ray equipment is used. Of course, the instrument industry also provides a 3D-X-ray equipment system, which can perform more detailed inspection of assembly defects, but the speed is too slow and the effect is limited. At best, it can only be used as a problem analysis tool.

PCBA AOI inspecting machine

The AOI equipment is generally set after the reflow oven, and the inspection is performed after the reflow soldering is completed, but after the reflow soldering, a certain distance (time) must be left to cool the PCBA, and a manual visual inspection station is installed thereafter.

Therefore, currently the more practical approach is to use the AOI system for general assembly inspection after reflow and timely feedback of problems, and then perform electrical testing, repair, and retesting. At present, it is still difficult to completely rely on the AOI system to solve all PCBA assembly problems.