Verification of Paperboard Chain of Custody Public Scope Schedules
Public scope schedule verification requires matching board product categories and claim systems on official registers to downstream delivery notes.
Caliper Specification
Thickness Standard
Microscopic distance between the upper and lower surfaces of a paperboard sheet under standardized static pressure defines its structural thickness profile. Caliper specification sets the nominal distance in micrometres that mills must maintain across a production run to ensure mechanical compatibility with converting equipment. Mechanical dead-weight micrometers apply a constant pressure of one hundred kilopascals over a defined anvil area to yield reproducible measurements across compressible fibrous matrix structures.
Structural stiffness scales non-linearly with board thickness, making precise thickness control critical for folding carton performance.
Process Control
On-line thickness gauges pass non-contact sensors across moving paper webs to regulate calender nip pressures continuously. Machine operators adjust steel calender roll temperature profiles and hydraulic loading to eliminate cross-web thickness variation. Variations in fibrous density alter thickness independently of sheet weight, requiring separate monitoring of density metrics during wet-end drainage adjustments.
Caliper specification monitoring prevents carton feed jams on high-speed gluing equipment by maintaining constant sheet profiles throughout long converting runs.
Operational Limit
Production boundaries establish minimum and maximum sheet thickness values for converted packaging materials. Standard commercial specifications enforce tolerance bands within plus or minus five percent of target micro-meter values to preserve crease channel geometry. Excessive thickness variations disrupt die-cutting depth settings, resulting in surface liner cracking during carton erection.
Sub-specification board thickness leads to inadequate package stacking strength, resulting in structural warehouse box collapse under vertical compression loads.