Cross Sectional Verification
Destructive physical examination of a dedicated test vehicle confirms internal printed circuit board integrity. Quality control departments use microsection coupon analysis to inspect plated through holes and internal layers for material voids, plating thickness, or drilling defects. Technicians extract the sample from a production panel edge before final board routing.
They mount the specimen in thermoset resin, grind the face to the vertical centerline, and polish the surface to reveal a planar view of internal features. Examiners then subject the prepared plane to optical or electron microscopy to measure feature dimensions against design specifications.
Geometric Compliance
Accurate determination of copper wrap thickness at the barrel center relies on the quality of the sectioning plane. Operators must align the cutting path precisely with the center of the hole to ensure representative measurements. Variations in grinding depth produce skewed readings of annular ring width or dielectric thickness.
Calibration of the mechanical system holds importance during the preparation phase to prevent smearing of soft copper into nonconductive resin voids. Metallurgical integrity often depends on the absence of such artifacts during the imaging process.
Performance Validation
Regulatory bodies define specific criteria for acceptable void percentages and dielectric spacing within high reliability hardware. Inspectors compare these quantitative results against established build requirements to authorize the release of a production lot. Failure to meet thickness minima or width tolerances triggers an investigation into the plating chemistry or registration accuracy of the drilling equipment.
Properly executed data collection from these samples provides the final evidence for internal structural conformity.
