Laser Line Triangulation Profilometry Principles on Continuous Paperboard Substrates
Inline blue laser triangulation measures paperboard surface topography at high speeds by overcoming fiber light penetration and isolating mechanical flutter.
Peak Extraction Algorithm
Signal Boundary
A peak extraction algorithm isolates true substrate deflection anomalies from background web tension oscillation during high speed converting operations. Calibrating this routine requires setting a baseline noise threshold that prevents false positive defect flags during heavy board lamination runs. Machine operators configure the detection window using millimetre per second velocity gradients rather than raw amplitude counts.
Substrate stiffness variations across a recycled linerboard web create persistent baseline chatter that invalidates standard threshold filters.
Contour Resolution
Mathematical derivatives isolate the precise apex of a deformation signal before secondary harmonic interference distorts the measurement. Converting lines running at high speeds generate mechanical resonance that masks subtle caliper losses in corrugated packaging material. Signal processing software applies a second order Savitzky-Golay filter to smooth high frequency jitter without shifting the temporal location of the actual defect apex.
Translating raw sensor voltages into accurate micro-metre thickness values demands precise synchronisation between the rotary encoder and the optical detector clock.
Tolerance Mapping
Software parameters establish the maximum allowable deviation between nominal caliper targets and the measured peaks recorded during continuous production runs. Converting facilities apply these algorithms to verify that multi-ply folding boxboard maintains uniform thickness across the entire parent roll width. Exceeding the predefined extraction boundary triggers an automated sorting gate diverter before defective sheets reach the sheeter knife assembly.
Production tolerances narrow significantly when processing coated graphic paper destined for luxury packaging applications.