- Friction in paper and paper compounds (coefficient of friction) is important for their further processing in automatic systems. The coefficient of friction can be measured as "paper against paper" or "paper against other material."
- During measurement of the coefficient of friction, properties such as static and dynamic friction are determined in accordance with TAPPI T 549.
- ZwickRoell has friction devices and programs for determining both values. These provide the user with reliable values and help in finding a solution to packaging or printing problems.
- Horizontal plane method: static and dynamic friction are determined using a sled. Friction device as per TAPPI with fast specimen gripping.
- Strip method: two strips of material are drawn in opposite directions over rollers pressed together. Advantages of this method: Only the surfaces which have not yet been in contact with each other are tested.
- The ZwickRoell testing software determines friction properties such as static and dynamic friction, peak values and upper and lower averages of the peaks. In one operation the user obtains the results needed to enable further processing of the materials.
Of the horizontal plane methods, tests to TAPPI T 549 are used most often. The ISO method is considerably more complex, as the entire test procedure (setting up and movement of the sled) is partially automated. Investigations into tests on corrugated board have shown that ISO and TAPPI values agree.