The edge crush test is a laboratory
test method
A test method is a method for a test in science or engineering, such as a physical test, chemical test, or statistical test. It is a definitive procedure that produces a test result. In order to ensure accurate and relevant test results, a test met ...
that is used to measure the cross-direction crushing of a sample of
corrugated board
Corrugated fiberboard or corrugated cardboard is a type of packaging material consisting of a fluted corrugated sheet and one or two flat linerboards. It is made on "flute lamination machines" or "corrugators" and is used for making corrugated ...
. It gives information on the ability of a particular board construction to resist crushing. It provides some relationship with the peak top-to-bottom compression strength of empty singlewall regular slotted containers in laboratory conditions.
The edge crush resistance ''R'', expressed in
kilonewton
The newton (symbol: N) is the unit of force in the International System of Units (SI). It is defined as 1 kg⋅m/s, the force which gives a mass of 1 kilogram an acceleration of 1 metre per second per second. It is named after Isaac Newton in ...
s per meter (kN/m) is calculated by the equation:
, where
is the mean value of the maximum force and is measured in newtons. More details are laid down in ISO 3037.
Corrugated fiberboard can be evaluated by many material test methods including an edge crush test. There have been efforts to estimate the compression strength of a box (usually empty, regular singlewall slotted containers, top-to-bottom) based on various board properties. Some have involved
finite element analysis
The finite element method (FEM) is a popular method for numerically solving differential equations arising in engineering and mathematical modeling. Typical problem areas of interest include the traditional fields of structural analysis, heat ...
. One of the commonly referenced
empirical
Empirical evidence for a proposition is evidence, i.e. what supports or counters this proposition, that is constituted by or accessible to sense experience or experimental procedure. Empirical evidence is of central importance to the sciences and ...
estimations was published by McKee in 1963.
This used the board ECT, the MD and CD flexural stiffness, the box perimeter, and the box depth. Simplifications have used a formula involving the board ECT, the board thickness, and the box perimeter. Most estimations do not relate well to other box orientations, box styles, or to filled boxes.
In order to calculate the value of BCT (
Box compression test
The container compression test measures the compressive strength of packages such as boxes, drums, and cans. It usually provides a plot of deformation vs compressive force.
It is commonly used to evaluate shipping containers made of corrugated f ...
), the formula of McKee would be the easiest but also the least accurate. The ratio of height to the circumference must be greater than 1:7; even then, are many reservations.
Simplified McKee formula:
:
::BCT = Box compression test in Pounds
::U = box outline in inch
::d = thickness of corrugated board in inch
References
* ISO 3037:2007-03, ''Corrugated fibreboard - Determination of edgewise crush resistance''
{{DEFAULTSORT:Edge Crush Test
Materials testing