Can our PCB optical inspection equipment measure multiple items at once?
Release date:
2015-11-13 00:00
Source:
In SMT production, multiple components are usually undetectable—can our AOI system handle this?
Multiple components being misplaced represent a significant challenge in AOI inspection, primarily due to "uncertain positioning." In other words, "foreign objects" could potentially appear anywhere on the entire circuit board—whether it’s directly on component pads where they shouldn’t be or even in completely unexpected areas. While detecting components stuck in the wrong locations (e.g., on pads where parts shouldn’t be) is relatively straightforward, the "multiple-component misplacement" scenario—as described by the customer, which typically involves foreign objects appearing at *any* spot on the board—is something that Star River’s AOI system can indeed identify. However, practical implementation of this capability still comes with certain limitations.
First, we need to set a certain size limit for foreign objects—specifically, they can’t be too small. Generally speaking, if an object is smaller than the width of the silkscreen markings on the circuit board, it becomes difficult to detect.
Secondly, if the foreign object is metallic, its distinct reflective properties make it easier to detect—otherwise, if it matches the color of the base material or closely resembles the screen-printed design, it becomes much harder to spot.
Also, when programming, you need to ensure that the entire PCB surface is included within the inspection FOV—only the programmed area will actually be inspected.
Our AOI features a "block all component windows" function, meaning that once a component window (such as the component body, pads, or IC pins) is drawn within a specific area, its contents will be masked in the "stain detection window." This prevents "false stain alarms" caused by variations on the component surface or changes in solder on component pads. This capability is one of the key technologies enabling our company’s AOI system to perform "multi-part detection." Other critical technologies include "image feature description," which ensures that only metallic foreign objects are flagged, while accurately ignoring false alarms triggered by shifts in screen-printing patterns.
Of course, detecting "multiple components" will naturally require scanning more FOV areas than simply inspecting individual components and solder joints, so the overall inspection speed is bound to slow down.
Previous page
Next page
