Volumetric Metrology
Three-dimensional optical inspection using projected fringe patterns enables the precise measurement of solder volume and component heights on assembled circuit boards. An automated inspection system utilizing structured light 3d aoi projects sinusoidal light grids onto the board surface and captures the deformed patterns with top-down or angled cameras. This technique translates phase variations of the reflected light into accurate height measurements for each pixel on the board.
It allows quality control systems to detect defects that are invisible to two-dimensional systems, such as lifted leads or subtle component tilt.
Defect Detection
Analyzing the calculated three-dimensional profiles allows the system to verify the volume, height, and area of each solder joint. Traditional inspection often struggles with height-based defects like head-in-pillow or coplanarity issues, whereas this approach captures the complete surface topography. If the solder paste volume falls below the specified tolerance, the system flags the board for rework before it undergoes thermal reflow.
This early detection is essential for reducing scrap rates on complex assemblies with fine-pitch components.
Process Feedback
Closed-loop feedback systems use this height data to optimize the solder paste printer and component placement machines. When volume drift is detected, the system adjusts the print settings automatically to prevent future errors. This real-time control maintains process stability during long production runs.
