Coefficient of Friction

Friction of paper and paper compounds is important for further processing in automatic systems. For the determination of the coefficient of friction, an important factor is the material of the two surfaces to be measured, "paper against paper", or "paper against other materials". Another deciding factor is whether the static friction or the dynamic friction is to be measured.  

Zwick offers tools and software programs for all of these methods. This gives the user confidence in the test results and then ultimately in finding a solution for packing or printing problems. Two basic measuring techniques are available:  

Most tests using the "Horizontal Plane Methods", are tested to TAPPI (TAPPI T 549 and TAPPI T 816). The ISO methods are more complicated, since the entire measuring operation (application and driving of the sled) must not be performed manually. Initial studies of tests on corrugated board showed that the values tested to ISO correspond to TAPPI.  

Zwick-Software testXpert^® II determines a wide range of friction results: static and dynamic friction, peak values, upper and lower median of peaks. This provides the user with results that are needed for subsequent material processing.  

The advantages: 

• Friction units to TAPPI with fast placement of the specimen 
• A wide variety of friction tests results are available in testXpert^® II  
• Strip friction unit for tests on „virgin" surfaces
• The "Horizontal Plane Method", in which the static and kinetic friction are determined with one sled 
• The "Strip Method": two material strips are pulled over pressed rolls in opposition to one another. The advantage of this method is that the only surfaces that are tested are the ones that have not been in contact with each other.