Positional Adjustment
Positional mapping software calculates the offset between theoretical copper coordinates and the actual locations of global markers on a fabricated panel. The fiducial displacement matrix records the translation and rotation required to align the pick and place machine with the physical board. This data set compensates for the material shrinkage that occurs during high temperature lamination.
Inspection Verification
Coordinate values for every fiducial are compared against the original Gerber files by the vision system of the assembly equipment. When a fiducial displacement matrix is generated, it applies a mathematical transform to every placement coordinate in the job file. This adjustment ensures that small components land precisely on their pads even if the substrate has scaled or warped slightly during previous thermal steps.
The matrix typically accounts for linear scaling in both the horizontal and vertical axes while correcting for any shearing effects in the panel. Mathematical interpolation helps determine the correct placement for parts located between the measured markers.
Assembly Alignment
Modern assembly lines require this correction to maintain high yields on dense boards. Without a fiducial displacement matrix, the cumulative error from board fabrication would cause components to sit off-center or bridge adjacent pads. Inspection machines also use this data to calibrate their own optical sensors before checking for defects.
