Cold Foil Register Drift as the Stack Warms across a Shift
Stack thermal buildup causes substrate shrinkage and mechanical expansion, driving cold foil register drift across continuous production shifts.
Thermal Scrap
Heat Loss
Manufacturing waste generated during the heat-sealing or thermal forming of polymer-coated paperboard represents a distinct category of production loss. The thermal scrap includes the trimmed edges and misaligned pieces of board that are exposed to high temperatures during the carton-forming process. This material must be kept separate from clean, dry waste because the heat can degrade both the paperboard fibers and the polymer coating.
It cannot be easily recycled in standard paper mills without specialized sorting.
Scrap Management
Separation of this material occurs at the discharge end of the high-speed carton filling and sealing line. When thermal scrap is generated, it is conveyed to a dedicated baling station to prevent it from mixing with the raw board scrap. Converting plants must track the volume of this material to monitor the heating efficiency of the sealing jaws.
A high level of heat-affected waste indicates that the machine’s thermal controls are misaligned or running too hot.
Process Constraint
Reuse of these polymer-coated fibers is limited by the heat-induced adhesion of the plastic layer. High-temperature treatment makes the polymer coating stickier, which increases the risk of contamination in the pulper. This restriction forces most of this waste into secondary recycling channels or energy recovery.