Piezoelectric Stress Wave Analysis in Rotary Die Scoring Operations
Piezoelectric stress wave monitoring detects cartonboard score cracking in real time by capturing high-frequency elastic strain transients at rotary die nips.
Bandpass Filtering
Frequency Selection
Signal processing algorithms extract targeted frequency bands from raw vibration or thickness transducer inputs while attenuating low frequency baseline drift and high frequency electrical noise. Digital bandpass filtering isolates specific mechanical frequencies generated by rotating press rolls, corrugator rolls, and calender nips on paper machines. The isolation of narrow spectral windows allows monitoring systems to detect bearing defects and roll eccentricities long before physical damage alters board quality.
Continuous calculations highlight amplitude growth within defined frequency limits.
Signal Conditioning
Continuous calculation of web caliper and basis weight profile relies on high rate transducer data passed through selective frequency windows. In online paper machine sensor arrays, bandpass filtering separates fundamental machine speed vibrations from periodic structural resonances. Raw signals from piezoelectric sensors pass through digital infinite impulse response filters designed with sharp roll-off characteristics.
Attenuating outer frequencies prevents aliasing and stabilizes machine direction profile algorithms during speed transitions.
Operational Limit
Dynamic response degradation occurs when filter bandwidth is set too narrow relative to machine speed fluctuations. Phase lag increases near corner frequencies, distorting real time edge detection signals on high speed slitter rewinder beds. Filter coefficients must adjust dynamically when machine operating speeds shift across product grades.