The relationship between board stiffness and crease stiffness, or crease recovery (spring back) as it is also known, is an important factor in the machine performance of cartons.
Crease stiffness testing is performed using a Smithers Pira board and crease stiffness tester (CBT2). Board stiffness is determined by bending a 50mm length test piece of board through a 15° angle. Crease recovery is determined by holding a formed crease at 90° and measuring the recovery force after 15 seconds. The maximum folding force is also recorded.
This information can be used to evaluate the crease performance for a range of crease settings, or to compare the performance of a selection of different carton board materials.
Standards and Accreditation
Crease stiffness testing is performed to British standard BS 6965:1 and board stiffness testing in accordance with BS 3748 and ISO 2493.