Machines that use a fourdrinier to make bleached folding carton and cupstock have to handle high basis weights that provide the caliper necessary for these grades. This thick sheet of paper quickly suffers when the weight goes up and down. Breaks in the press are more frequent and take longer to re-thread. And of course, there is the lost on-quality tons when the caliper drops below specification.
A machine making 140.000 MT/year of bleached cupstock was suffering from these issues. Off quality paper was cost 200.000€/year per 1% of lost production.
BTG experts completed a dilution capability map and audited the consistency variability reduction chain. It was found that each machine was in desperate need of improved variability reduction from the consistency loops. Upgrades to the transmitter quality and training of the operators and lab cross-checkers resulted in significant reduction in weight swings due to consistency.
The reduction in off-quality was signed off by the customer at 1% reduction, a value of 200.000€/year! The mill immediately undertook the same project on the bleached folding carton machine that sat across the aisle with similar success!
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