Carton opening force measurements can be used to characterise poorly performing cartons or compare carton boards and designs.
The term "carton opening force" is used to describe the resistance to erection of side seam glued cartons. This carton property can be measured in two main ways.
Diagonal loading method
The carton has a force applied across the collapsed carton from one 180 degree fold line to the other. It is usual to record the peak value of the force during erection.
Rotational opening method
The carton opening force is measured by rotating the carton open using an apparatus designed to reproduce the action of an epicyclical cartoning machine.
One main panel is secured and a force applied to the side panel by a bar that pivots on the axis of its crease to erect the whole carton towards the rectangular shape.