Predicting Set off Migration in Stacked Packaging Board under Non Uniform Compression
Predicting set-off migration requires calculating local pressure peaks across board caliper variations to set safe pile heights and barrier coat weights.
Contact Pressure Mapping
Spatial Measurement
Tactile sensor arrays quantify the force distribution between compressed mechanical surfaces within converting machinery. Piezoelectric or resistive sensor sheets register spatial load variations across the full width of rotating cylinders under dynamic load. Data acquired through contact pressure mapping reveals localized stress concentrations caused by roll deflection, rubber cover wear, or journal misalignment.
Unbalanced pressure distributions create uneven fluid metering in coater units and irregular ink transfer in offset printing presses. Quantitative readings permit operators to calibrate nip geometry prior to running sensitive paperboard substrates.
Nip Mechanics
Roll flexure under hydraulic loaded bearing blocks creates an uneven pressure profile along the web width, concentrating force at the cylinder edges while relieving tension near the center. Crowned rolls correct for this bending deflection, yet improper crown calculations lead to center pinched or edge starved nip zones. Utilizing contact pressure mapping during static setup pinpoints mechanical deviations across the nip impression area.
Variations in rubber sleeve hardness alter the effective contact area, changing peak nip pressure without altering total load meter readings. Precise mapping identifies localized high pressure points that crush paperboard caliper, preserving stiffness and structural rigidity in corrugated fluting. Coating units rely on uniform nip force to maintain constant film thickness across the moving web.
Transfer Uniformity
Digital matrix sensors record live pressure gradients as nip rolls rotate under operational speeds and temperatures. Process engineers inspect these real time profiles during contact pressure mapping to establish repeatable nip parameters across production shifts. Detailed contact pressure mapping reduces substrate crush defects across heavy paperboard grades.