Edge Strip
Narrow margins of paper or paperboard are continuously sliced from the outer edges of the parent roll as it is rewound into smaller finished rolls. This discarded material, known as winder trim, is removed to ensure that the finished rolls have straight, clean, and uniform edges. It represents a necessary loss of width to maintain the dimensional quality of the shipped product.
Width Optimization
Slitting blades on the slitter-winder must be kept sharp and correctly positioned to prevent ragged edges or dust on the wound rolls. Since paperboard varies in thickness across the machine width, the outer edges of the web are often thinner or less uniform. Slicing off these uneven margins prevents soft edges in the finished rolls, which could cause tension issues during subsequent printing or converting.
Fiber Recovery
Disposal of this excess material is handled automatically by pneumatic systems that shred and transport the strips back to the pulper. This continuous recovery of clean fibers improves the overall material efficiency of the mill by recycling the trim directly into the stock preparation system. Minimizing the width of the trim while maintaining edge quality is an ongoing focus for winder operators.
Reducing the trim width by even a few millimeters can yield cost savings over a long production run. This optimization requires precise positioning of the outer slitting knives.
