What is the purpose of die-cutting? Die-cutting (paper cutting, imposition): Arrange the cutting lines according to the box design (to minimise paper waste) and confirm the direction of the paper grain (with the grain). Ensure sufficient allowances are made for die-cutting standards (notches, bleed). The die-cutting parameters should be set to minimise paper waste.
How is die-cutting verified? Die-cutting (die, creasing): the precision of the cutting lines (die-cut lines) (standard tolerances) and the depth of the creases (fold lines); dies for irregular shapes (rounded corners, windows) must be tested. To verify die-cutting, fold a single box to check the alignment.
A single cardboard box must pass through four critical stages from a large sheet of paper to the finished product: whether the cutting is precise, whether the printing is accurate, whether the die-cutting is aligned, and whether the gluing is secure — any shortcut at any stage will compromise the quality of the box. This article clearly explains the production process for packaging boxes.
How is printing controlled? Printing (pre-press proofing, colour matching on press): Spot colours / four-colour process (colour matching standards), print density (both light and dark areas); colour variations in bulk production (within the same batch) must be spot-checked. Print control is based on the principle of ‘matching the proof box’.
How is inspection carried out? Batch inspection (spot-checking): dimensions (measured with calipers), rigidity (by hand), opening and closing (resilience), printing (colour variation comparison); Defective items (proportion) are determined according to AQL. Inspection rules are governed by ‘the sample selection’.
How is box gluing carried out? Box gluing (machine-glued, hand-glued): machine-glued (for high-volume production), hand-glued (for irregular shapes / high-end products); the adhesive used (white latex glue, hot-melt adhesive) is selected according to the production process; alignment of the box sides (all four sides aligned) must be inspected. The standard for box assembly is that the box must ‘open and close without coming apart’.
The production process for packaging boxes is a relay in which ‘not a single one of the four stages can be omitted’: paper-saving blank cutting, colour-accurate printing, precise die-cutting, and secure box assembly — each stage must be closely monitored to ensure the boxes can withstand being unpacked upon leaving the factory.
