Pulp Index Pass through Clauses inside a Paper Supply Contract
Ground paper supply pass-through clauses in verified dry fibre weight, strict index lag rules, and active goods-in batch audits to block supplier overcharges.
Lag Calibration
Sensor Delay
Time-delay adjustment calculations aligning online scanner measurement signals with physical paper machine reel positions compensate for transportation lag along the wet end and dryer sections. Lag calibration synchronizes quality scanner readings with specific stock valve movements and actuator responses across the paper machine. Proper alignment ensures automated control systems assign measured basis weight or moisture variations to correct physical machine locations.
Mathematical calibration stops applying during process shut-down or static web conditions.
Signal Alignment
Papermaking involves continuous web movement over long distances from headbox stock injection to final reel winding, introducing significant transport delay. Implementing lag calibration enables automated quality control systems to map downstream scanner signals back to headbox dilution actuators accurately. Without precise delay compensation, control algorithms adjust incorrect stock valves, creating artificial profile variations across the web.
System engineers calculate lag times based on machine speed, dryer roll distance, and scanner traverse frequency. When machine speed changes during production acceleration, dynamic lag algorithms recalculate transport delays in real time. Accurate time-alignment prevents control loop oscillations and reduces grade change transition scrap.
Process optimization relies on calibrated signal timing to maintain tight basis weight and caliper profiles.
System Limit
Process dynamics restrict delay compensation accuracy during sudden machine speed shifts or web breaks. Performing lag calibration requires continuous speed encoder inputs and dynamic delay tracking algorithms within the quality control system framework. Uncalibrated lag errors degrade cross-direction profile control, leading to edge-to-edge basis weight variability.
Calculations lose precision during rapid speed transitions before steady-state transport times re-establish.