Statistical Process Control Fundamentals in Packaging Substrate Converting
Statistical process control in substrate converting relies on sub-grouping across machine direction variance and isolating non-normal barrier defects.
Defect Containment
Quality Isolation
Immediate quarantine of substandard board prevents defective material from advancing through the subsequent stages of print and conversion. Implementing systematic defect containment protocols ensures that issues such as misregistrations or ply separation are resolved within the production facility. This action minimizes the risk of sending faulty cartons to the filling lines.
Inspection Protocol
Automated optical scanners mounted on high-speed presses detect surface flaws and trigger active rejection systems. These cameras scan the moving paper web to find deviations in color or ink density. When a flaw is detected, the system marks the affected sheet or roll, allowing the operator to separate the material from the approved batch before it reaches the shipping department.
This automated tracking is supplemented by manual checks at the slitter-winder, where rolls are inspected for edge tears and core defects that could cause web breaks on the customer’s printing press.
Supply Protection
Isolating substandard board protects the converter from the financial liabilities associated with line downtime at the customer’s plant. When a packaging line jams due to warped board, the cost of the lost production time is often charged back to the converter. Efficient containment ensures that only board meeting the agreed specifications is dispatched.