The ring crush test is similar to the strip crush test in that the strength of liner or fluting is measured both in the machine direction and perpendicular to it. The results in this test are highly dependent on proper specimen preparation. Specimen and test fixture must be exactly parallel to ensure accurate determination of the ring crush strength. 

As the ring crush test provides information about specimen buckling behavior rather than crush behavior, it is increasingly being replaced by the strip crush test.   

Advantages: 

• lightweight, precision-guided compression platens prevent lateral movement of the specimen during the test 
• compression platens suitable for mini-flute board are available from Zwick´s standard range 
• automatic detection of collapse of all flutes avoids misinterpretation in the flat crush test 
• inserts for the ring crush test fit easily into the compression platens; lateral movement of the specimen is again prevented 
• data graph of the test run is standard for all tests