If the creasing operation is performed incorrectly—either too weakly or with the wrong profile—it severely compromises the structural integrity of the print’s surface coatings. When a coated thick material (like one with UV varnish or lamination) is folded without a proper crease, the coating, which is less elastic than the paper/board beneath it, is forced to stretch beyond its limit. This immediately leads to cracking (whitening of the surface) or detachment (peeling) of the coating along the Fold Line, especially visible in dark-colored designs.

This failure directly impacts the quality of the subsequent Folding process. A poor crease line means the folding machine or manual assembly cannot achieve a sharp, clean bend according to the Dieline. Instead, the material folds unevenly or resists the fold entirely, leading to distorted packaging and manufacturing waste. A well-executed crease provides the material with a pre-defined hinge, making the folding process smooth, accurate, and essential for the functionality detailed by the Structural Design.