Non-Contact Caliper Measurement Systems on High Speed Packaging Board Lines
Non-contact optical gauges eliminate mechanical board compression on high-speed lines, enabling tighter cross-machine caliper targets and reduced fiber mass.
Edge Roll Off
Caliper Gradient
Caliper gradient measures the unintended thinning occurring within the outer two millimetres of a converted sheet. Edge roll off develops when slitting blades exert excessive lateral pressure against the web during final trimming. Coaters apply excessive tension to the substrate periphery, producing a localized thickness drop that compromises subsequent packaging conversion.
Press operators compensate for this caliper variation by adjusting impression cylinders, but uneven caliper limits high speed folding carton integrity.
Width Tolerance
Width tolerance defines the exact specification threshold separating acceptable trimmed stock from unusable waste. Slitter operators monitor blade sharpness continuously to prevent the lateral crushing that causes edge roll off. Substrate compressibility dictates how much tension the perimeter can withstand before permanent deformation occurs during winding.
Converters measure this caliper loss using precision micrometers across five distinct points along the transverse direction.
Conversion Yield
Conversion yield calculates the usable surface area remaining after discarding defective perimeter strips affected by edge roll off. Die cutters reject the outer millimeters of wide reels because inconsistent caliper prevents reliable glue penetration during box erection. Premium packaging lines demand uniform thickness profiles to ensure high speed gluing stations apply adhesives evenly without joint failure.
Material waste increases whenever slitter dullness shifts the caliper gradient beyond established mill standards.