Precreasing

Precreasing is the practice of creating shallow crease lines, or scored lines, on a material before folding. The goal is to guide the subsequent fold, improve accuracy, and reduce tearing or distortion, especially on thicker or coated papers and boards.

Applications include packaging and carton fabrication, origami and paper crafts, and, in textiles and leather work, guides for seams or decorative folds. In manufacturing, pre-creased lines enable faster, more consistent assembly of flat sheets into complex shapes.

Techniques involve scoring with a blade or wheel to weaken the fiber along the line, followed by bending along the crease. Tools commonly used are scoring blades, a bone folder, creasing boards, and rollers. Some materials respond to heat and pressure, using heat-creasing for plastics or laminated sheets.

Best practices include testing crease depth on scrap material, aligning creases with existing marks, and avoiding excessive depth that can cause cracking or weakening. Over-creasing may compromise strength, while under-creasing can hinder alignment. Pre-creasing is typically one step in a broader folding strategy rather than a substitute for precise cutting or scoring.