Most factories still inspect the way they did twenty years ago: build, then check. Parts move down the line, an AOI station at the end sorts good from bad, and the rejects go to rework or scrap. The arrangement is easy to understand and easy to buy. Its weakness is timing. By the time the defect is found, the process that caused it has already made dozens more.
At micro-scale joining the delay is expensive. A solder joint on a camera module or a fine-pitch interconnect is formed in milliseconds and cannot be improved afterwards. If the volume drifts, the wetting changes or the alignment shifts by a few microns, the only remaining choice is accept or reject. Inspection at the end of the line records that loss accurately. It does nothing to prevent it.
The alternative is to put vision inside the process. Cameras confirm position before the laser fires, measure the result immediately after, and feed both back to the controller. When the system notices drift across a run, it can correct a parameter or stop the line before the trend turns into scrap. Inspection stops being a gate and becomes a sensor, and the data it produces has a direct use instead of filling an archive.
This is the logic behind integrating AOI with the soldering head rather than sending parts to a separate station. It also lays the foundation for the next step. A process that already measures every joint, and already knows the parameters that produced it, has exactly the paired data that learning systems need to predict defects instead of only detecting them.
The strategic read: yield is decided at the moment of processing, so that is where inspection has to be. Factories that keep quality as a separate department at the end of the line will keep paying for rework. Those that close the loop at the point of joining will turn inspection from a cost of quality into a control system.