- TAPPI-T 818 – Ring crush of paperboard
- The ring crush test correlates with edgewise compression strength of paperboard (1).This method is intended for paperboard between 0.28 mm (0.011 in.) and 0.51 mm (0.020 in.) thick.
- It may be used with less reliability for paperboard as thin as 0.18 mm (0.007 in.), and as thick as 0.76 mm (0.030 in.). The short span compression test, TAPPI T 826 “Short Span Compressive Strength of Paperboard,” measures edgewise compressive strength over a broader range of thickness.Ring crush is also measured in TAPPI T 822 “Ring Crush of Paperboard (Rigid Support Method),” which uses a rigid platen compression machine instead of the flexing beam of this method. T 822 has a tighter precision.
Ring Crush (RCT)
Ring Crush Test for measuring the resistance of paper and paperboard to edgewise compression.
A special jig is used during the test to hold the test piece in a ring form