Ring Crush

Definition
Compression strength correlates with the vertical stacking strength potential of combined board. Ring crush is the older and more widely established method of testing compression strength. It is a measure of the force that is required to collapse a 6-in. ring of containerboard that is ½ in. high. Ring crush is normally measured so that the crushing occurs in the cross-machine direction.

Influence
Ring crush value has no direct effect on corrugated combining or converting operations.

Potential Problems
Failure to meet specified minimums of ring crush value may result in boxes that will not meet stacking strength expectations.

Source
McGrattan, W. "Key characteristics of linerboard, corrugating medium, and roll stock mechanical condition and their influence on the manufacture of corrugated products, part 1." Tappi Journal (1990): 99-108.

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