Chain of Custody Credit Accounting Protocols for Packaging Board Mills
Mill credit accounting requires dry fiber mass balance calculations, yield factor adjustments for coating mass, and strict rolling credit ledger management.
Edge Trim Waste
Material Loss
Narrow strips of paper or board removed from the sides of a moving web during the slitting process ensure that the final reel has clean and uniform edges. While edge trim waste is a necessary part of manufacturing to reach precise widths, it represents a portion of the material that does not reach the customer. This discarded material is typically vacuumed away and returned to the pulper for reprocessing into new stock.
Operational Efficiency
Setting the width of the trim depends on the stability of the web as it travels through the paper machine or the corrugator. If the web wanders from side to side, a wider trim is required to prevent the finished product from having uneven edges. Operators strive to minimize this width to improve the overall deckle utilization of the machine.
A machine with a width of five meters might lose fifty millimeters on each side to trim. This loss is factored into the production cost and the carbon footprint of the batch.
Converting Accuracy
In the converting stage, trimming ensures that the printed image aligns perfectly with the physical edge of the sheet. It removes any registration marks or color bars used during the printing process.