Deposition Measurement
Process control systems quantify the three dimensional topography of printed materials immediately following the stencil printing stage. In a typical production environment, automated solder paste inspection systems use structured light or laser triangulation to calculate volume, area, height and position. These measurements determine if the print deposit matches the aperture design within specified tolerances.
Volume Consistency
Solder paste deposits must maintain specific volumetric thresholds to prevent assembly failures. If automated solder paste inspection detects a low volume condition, the board is diverted for cleaning before components are placed. Such intervention prevents insufficient solder joints or open circuits during reflow.
High volume readings conversely warn of potential bridging between fine pitch pads.
Defect Prevention
Statistical analysis of the data collected during the inspection cycle identifies trends in stencil clogging or paste degradation. Because automated solder paste inspection provides real time feedback on the printing process, operators adjust squeegee pressure or cleaning cycles before defects occur. This step effectively closes the loop on the front end of the surface mount technology line.
It eliminates the rework costs associated with post reflow repairs. Quality assurance teams use the resulting metrics to validate the stability of the printing operation over long production shifts.
