Paper Equilibrium
Gravimetric measurement quantifies the mass of water held within a sample of paper or board against the mass of that same material after oven drying at a specific temperature. The moisture content of paper measured under iso 287 represents the ratio of water mass to the total wet mass of the specimen. Laboratory procedures require the weighing of a specimen before and after removing all moisture in a circulating air oven to calculate the precise water loss.
Calibration of the balance and the controlled environment of the drying chamber dictate the accuracy of these final results.
Conversion Variance
Paper fibres expand and contract in response to fluctuating levels of ambient humidity which impacts the final dimensions of a product during mechanical converting. Sheet fed offset printing relies on iso 287 to ensure the moisture levels of the stock permit registration accuracy across multiple color stations. Boards that exit the mill with improper water levels suffer from curling or wavy edges that obstruct the smooth passage of material through high speed vacuum fed machines.
Precise control of this metric prevents the static electricity buildup that interferes with precision folding and gluing operations in secondary packaging production.
Tolerance Management
Packaging lines demand strict control over the water weight of substrates to maintain the structural integrity of corrugated boxes during the filling process and subsequent palletization. A manufacturer uses iso 287 to establish the baseline moisture content for incoming material to ensure the board maintains the necessary stiffness for vertical stacking. Excess water weakens the bonds between cellulose fibres which causes compression failure when external loads reach the design limits of a container.
Consistent moisture values confirm that the material meets the structural specifications required for the intended distribution environment.
