Piezoelectric Sensor Frequency Response Calibration for Folding Boxboard Converting
Piezoelectric sensor frequency response calibration prevents amplitude distortion during high speed creasing by matching amplifier cutoff to rule strike transients.
Amplitude Attenuation
Signal Reduction
Physical phenomena involving energy loss during wave propagation determine how acoustic signals interact with fibrous materials. Measuring amplitude attenuation allows technicians to evaluate the internal bonding and elastic modulus of a paper sheet without destructive testing. The value represents the decrease in peak pressure or voltage as the pulse travels through the substrate.
Attenuation Mechanism
Fibers and air pockets within the board matrix scatter sound waves and convert mechanical energy into heat through friction and thermal exchange. When amplitude attenuation increases, it typically indicates a higher degree of porosity or the presence of internal delamination within the multi-ply structure. Low density grades show much higher losses than dense, highly calendered boards because the air-fiber interfaces provide more opportunities for signal scattering.
The relationship helps in monitoring the consistency of the refining process during production and ensures that the structural integrity of the packaging meets the required specifications for heavy duty use. Sensors placed across the web track these changes in real time to prevent the distribution of sub-standard material.
Process Boundary
Signal loss measurements depend heavily on the moisture content and the temperature of the sample. If the board is too wet, the water in the capillaries dominates the response and obscures the fiber properties. Results are usually normalized to a standard climate to ensure comparability between different production runs.