Bending resistance is defined as the force (in Newton) that is required to bend a rectangular test piece to a specified angle, when the test piece is fixed at one end and the force is applied to its free end.
Creasability is defined as the ability of the board to permit deep and narrow creases that are easy to fold and result in well-defined edges and corners. Foldability is defined as the ability of a creased blank to form a carton or graphical product with the desired shape and dimensions, with minimal spring-back force.
Why measure bending resistance or stiffness?
Bending resistance and stiffness is an important material property that can affect the product performance in many converting and end-use operations. Low bending resistance/stiffness causes runnability issues during printing of paper, foldability issues during converting of board into packaging boxes, and stackability issues during handling and storage of packaging boxes.
Why measure creasability?
Creasability impacts foldability during converting operations of packaging board, runnability on packaging machines, and stackability of packaging boxes during end-use applications. Creasability evaluation can be used to determine creasing tool dimensions, monitor creasing tool wear-out, determine what type of board is suitable for certain creasing tools and optimize processes to produce board with better folding properties.